Update apscheduler 3.5.0

lib/apscheduler/__init__.py

@@ -1,5 +1,10 @@
-version_info = (3, 0, 1)
+from pkg_resources import get_distribution, DistributionNotFound
-version = '3.0.1'
-release = '3.0.1'
 
-__version__ = release  # PEP 396
+try:
+    release = get_distribution('APScheduler').version.split('-')[0]
+except DistributionNotFound:
+    release = '3.5.0'
+
+version_info = tuple(int(x) if x.isdigit() else x for x in release.split('.'))
+version = __version__ = '.'.join(str(x) for x in version_info[:3])
+del get_distribution, DistributionNotFound

lib/apscheduler/events.py

@@ -1,25 +1,33 @@
-__all__ = ('EVENT_SCHEDULER_START', 'EVENT_SCHEDULER_SHUTDOWN', 'EVENT_EXECUTOR_ADDED', 'EVENT_EXECUTOR_REMOVED',
+__all__ = ('EVENT_SCHEDULER_STARTED', 'EVENT_SCHEDULER_SHUTDOWN', 'EVENT_SCHEDULER_PAUSED',
-           'EVENT_JOBSTORE_ADDED', 'EVENT_JOBSTORE_REMOVED', 'EVENT_ALL_JOBS_REMOVED', 'EVENT_JOB_ADDED',
+           'EVENT_SCHEDULER_RESUMED', 'EVENT_EXECUTOR_ADDED', 'EVENT_EXECUTOR_REMOVED',
-           'EVENT_JOB_REMOVED', 'EVENT_JOB_MODIFIED', 'EVENT_JOB_EXECUTED', 'EVENT_JOB_ERROR', 'EVENT_JOB_MISSED',
+           'EVENT_JOBSTORE_ADDED', 'EVENT_JOBSTORE_REMOVED', 'EVENT_ALL_JOBS_REMOVED',
+           'EVENT_JOB_ADDED', 'EVENT_JOB_REMOVED', 'EVENT_JOB_MODIFIED', 'EVENT_JOB_EXECUTED',
+           'EVENT_JOB_ERROR', 'EVENT_JOB_MISSED', 'EVENT_JOB_SUBMITTED', 'EVENT_JOB_MAX_INSTANCES',
            'SchedulerEvent', 'JobEvent', 'JobExecutionEvent')
 
 
-EVENT_SCHEDULER_START = 1
+EVENT_SCHEDULER_STARTED = EVENT_SCHEDULER_START = 2 ** 0
-EVENT_SCHEDULER_SHUTDOWN = 2
+EVENT_SCHEDULER_SHUTDOWN = 2 ** 1
-EVENT_EXECUTOR_ADDED = 4
+EVENT_SCHEDULER_PAUSED = 2 ** 2
-EVENT_EXECUTOR_REMOVED = 8
+EVENT_SCHEDULER_RESUMED = 2 ** 3
-EVENT_JOBSTORE_ADDED = 16
+EVENT_EXECUTOR_ADDED = 2 ** 4
-EVENT_JOBSTORE_REMOVED = 32
+EVENT_EXECUTOR_REMOVED = 2 ** 5
-EVENT_ALL_JOBS_REMOVED = 64
+EVENT_JOBSTORE_ADDED = 2 ** 6
-EVENT_JOB_ADDED = 128
+EVENT_JOBSTORE_REMOVED = 2 ** 7
-EVENT_JOB_REMOVED = 256
+EVENT_ALL_JOBS_REMOVED = 2 ** 8
-EVENT_JOB_MODIFIED = 512
+EVENT_JOB_ADDED = 2 ** 9
-EVENT_JOB_EXECUTED = 1024
+EVENT_JOB_REMOVED = 2 ** 10
-EVENT_JOB_ERROR = 2048
+EVENT_JOB_MODIFIED = 2 ** 11
-EVENT_JOB_MISSED = 4096
+EVENT_JOB_EXECUTED = 2 ** 12
-EVENT_ALL = (EVENT_SCHEDULER_START | EVENT_SCHEDULER_SHUTDOWN | EVENT_JOBSTORE_ADDED | EVENT_JOBSTORE_REMOVED |
+EVENT_JOB_ERROR = 2 ** 13
+EVENT_JOB_MISSED = 2 ** 14
+EVENT_JOB_SUBMITTED = 2 ** 15
+EVENT_JOB_MAX_INSTANCES = 2 ** 16
+EVENT_ALL = (EVENT_SCHEDULER_STARTED | EVENT_SCHEDULER_SHUTDOWN | EVENT_SCHEDULER_PAUSED |
+             EVENT_SCHEDULER_RESUMED | EVENT_EXECUTOR_ADDED | EVENT_EXECUTOR_REMOVED |
+             EVENT_JOBSTORE_ADDED | EVENT_JOBSTORE_REMOVED | EVENT_ALL_JOBS_REMOVED |
              EVENT_JOB_ADDED | EVENT_JOB_REMOVED | EVENT_JOB_MODIFIED | EVENT_JOB_EXECUTED |
-             EVENT_JOB_ERROR | EVENT_JOB_MISSED)
+             EVENT_JOB_ERROR | EVENT_JOB_MISSED | EVENT_JOB_SUBMITTED | EVENT_JOB_MAX_INSTANCES)
 
 
 class SchedulerEvent(object):
@@ -55,9 +63,21 @@ class JobEvent(SchedulerEvent):
         self.jobstore = jobstore
 
 
+class JobSubmissionEvent(JobEvent):
+    """
+    An event that concerns the submission of a job to its executor.
+
+    :ivar scheduled_run_times: a list of datetimes when the job was intended to run
+    """
+
+    def __init__(self, code, job_id, jobstore, scheduled_run_times):
+        super(JobSubmissionEvent, self).__init__(code, job_id, jobstore)
+        self.scheduled_run_times = scheduled_run_times
+
+
 class JobExecutionEvent(JobEvent):
     """
-    An event that concerns the execution of individual jobs.
+    An event that concerns the running of a job within its executor.
 
     :ivar scheduled_run_time: the time when the job was scheduled to be run
     :ivar retval: the return value of the successfully executed job
@@ -65,7 +85,8 @@ class JobExecutionEvent(JobEvent):
     :ivar traceback: a formatted traceback for the exception
     """
 
-    def __init__(self, code, job_id, jobstore, scheduled_run_time, retval=None, exception=None, traceback=None):
+    def __init__(self, code, job_id, jobstore, scheduled_run_time, retval=None, exception=None,
+                 traceback=None):
         super(JobExecutionEvent, self).__init__(code, job_id, jobstore)
         self.scheduled_run_time = scheduled_run_time
         self.retval = retval

lib/apscheduler/executors/asyncio.py

@@ -1,28 +1,60 @@
 from __future__ import absolute_import
+
 import sys
 
 from apscheduler.executors.base import BaseExecutor, run_job
 
+try:
+    from asyncio import iscoroutinefunction
+    from apscheduler.executors.base_py3 import run_coroutine_job
+except ImportError:
+    from trollius import iscoroutinefunction
+    run_coroutine_job = None
+
 
 class AsyncIOExecutor(BaseExecutor):
     """
     Runs jobs in the default executor of the event loop.
 
+    If the job function is a native coroutine function, it is scheduled to be run directly in the
+    event loop as soon as possible. All other functions are run in the event loop's default
+    executor which is usually a thread pool.
+
     Plugin alias: ``asyncio``
     """
 
     def start(self, scheduler, alias):
         super(AsyncIOExecutor, self).start(scheduler, alias)
         self._eventloop = scheduler._eventloop
+        self._pending_futures = set()
+
+    def shutdown(self, wait=True):
+        # There is no way to honor wait=True without converting this method into a coroutine method
+        for f in self._pending_futures:
+            if not f.done():
+                f.cancel()
+
+        self._pending_futures.clear()
 
     def _do_submit_job(self, job, run_times):
         def callback(f):
+            self._pending_futures.discard(f)
             try:
                 events = f.result()
-            except:
+            except BaseException:
                 self._run_job_error(job.id, *sys.exc_info()[1:])
             else:
                 self._run_job_success(job.id, events)
 
-        f = self._eventloop.run_in_executor(None, run_job, job, job._jobstore_alias, run_times, self._logger.name)
+        if iscoroutinefunction(job.func):
+            if run_coroutine_job is not None:
+                coro = run_coroutine_job(job, job._jobstore_alias, run_times, self._logger.name)
+                f = self._eventloop.create_task(coro)
+            else:
+                raise Exception('Executing coroutine based jobs is not supported with Trollius')
+        else:
+            f = self._eventloop.run_in_executor(None, run_job, job, job._jobstore_alias, run_times,
+                                                self._logger.name)
+
         f.add_done_callback(callback)
+        self._pending_futures.add(f)

lib/apscheduler/executors/base.py

@@ -8,13 +8,15 @@ import sys
 from pytz import utc
 import six
 
-from apscheduler.events import JobExecutionEvent, EVENT_JOB_MISSED, EVENT_JOB_ERROR, EVENT_JOB_EXECUTED
+from apscheduler.events import (
+    JobExecutionEvent, EVENT_JOB_MISSED, EVENT_JOB_ERROR, EVENT_JOB_EXECUTED)
 
 
 class MaxInstancesReachedError(Exception):
     def __init__(self, job):
         super(MaxInstancesReachedError, self).__init__(
-            'Job "%s" has already reached its maximum number of instances (%d)' % (job.id, job.max_instances))
+            'Job "%s" has already reached its maximum number of instances (%d)' %
+            (job.id, job.max_instances))
 
 
 class BaseExecutor(six.with_metaclass(ABCMeta, object)):
@@ -30,13 +32,14 @@ class BaseExecutor(six.with_metaclass(ABCMeta, object)):
 
     def start(self, scheduler, alias):
         """
-        Called by the scheduler when the scheduler is being started or when the executor is being added to an already
+        Called by the scheduler when the scheduler is being started or when the executor is being
-        running scheduler.
+        added to an already running scheduler.
 
-        :param apscheduler.schedulers.base.BaseScheduler scheduler: the scheduler that is starting this executor
+        :param apscheduler.schedulers.base.BaseScheduler scheduler: the scheduler that is starting
+            this executor
         :param str|unicode alias: alias of this executor as it was assigned to the scheduler
-        """
 
+        """
         self._scheduler = scheduler
         self._lock = scheduler._create_lock()
         self._logger = logging.getLogger('apscheduler.executors.%s' % alias)
@@ -45,7 +48,8 @@ class BaseExecutor(six.with_metaclass(ABCMeta, object)):
         """
         Shuts down this executor.
 
-        :param bool wait: ``True`` to wait until all submitted jobs have been executed
+        :param bool wait: ``True`` to wait until all submitted jobs
+            have been executed
         """
 
     def submit_job(self, job, run_times):
@@ -53,10 +57,12 @@ class BaseExecutor(six.with_metaclass(ABCMeta, object)):
         Submits job for execution.
 
         :param Job job: job to execute
-        :param list[datetime] run_times: list of datetimes specifying when the job should have been run
+        :param list[datetime] run_times: list of datetimes specifying
-        :raises MaxInstancesReachedError: if the maximum number of allowed instances for this job has been reached
+            when the job should have been run
-        """
+        :raises MaxInstancesReachedError: if the maximum number of
+            allowed instances for this job has been reached
 
+        """
         assert self._lock is not None, 'This executor has not been started yet'
         with self._lock:
             if self._instances[job.id] >= job.max_instances:
@@ -70,50 +76,71 @@ class BaseExecutor(six.with_metaclass(ABCMeta, object)):
         """Performs the actual task of scheduling `run_job` to be called."""
 
     def _run_job_success(self, job_id, events):
-        """Called by the executor with the list of generated events when `run_job` has been successfully called."""
+        """
+        Called by the executor with the list of generated events when :func:`run_job` has been
+        successfully called.
 
+        """
         with self._lock:
             self._instances[job_id] -= 1
+            if self._instances[job_id] == 0:
+                del self._instances[job_id]
 
         for event in events:
             self._scheduler._dispatch_event(event)
 
     def _run_job_error(self, job_id, exc, traceback=None):
         """Called by the executor with the exception if there is an error  calling `run_job`."""
-
         with self._lock:
             self._instances[job_id] -= 1
+            if self._instances[job_id] == 0:
+                del self._instances[job_id]
 
         exc_info = (exc.__class__, exc, traceback)
         self._logger.error('Error running job %s', job_id, exc_info=exc_info)
 
 
 def run_job(job, jobstore_alias, run_times, logger_name):
-    """Called by executors to run the job. Returns a list of scheduler events to be dispatched by the scheduler."""
+    """
+    Called by executors to run the job. Returns a list of scheduler events to be dispatched by the
+    scheduler.
 
+    """
     events = []
     logger = logging.getLogger(logger_name)
     for run_time in run_times:
-        # See if the job missed its run time window, and handle possible misfires accordingly
+        # See if the job missed its run time window, and handle
+        # possible misfires accordingly
         if job.misfire_grace_time is not None:
             difference = datetime.now(utc) - run_time
             grace_time = timedelta(seconds=job.misfire_grace_time)
             if difference > grace_time:
-                events.append(JobExecutionEvent(EVENT_JOB_MISSED, job.id, jobstore_alias, run_time))
+                events.append(JobExecutionEvent(EVENT_JOB_MISSED, job.id, jobstore_alias,
+                                                run_time))
                 logger.warning('Run time of job "%s" was missed by %s', job, difference)
                 continue
 
         logger.info('Running job "%s" (scheduled at %s)', job, run_time)
         try:
             retval = job.func(*job.args, **job.kwargs)
-        except:
+        except BaseException:
             exc, tb = sys.exc_info()[1:]
             formatted_tb = ''.join(format_tb(tb))
-            events.append(JobExecutionEvent(EVENT_JOB_ERROR, job.id, jobstore_alias, run_time, exception=exc,
+            events.append(JobExecutionEvent(EVENT_JOB_ERROR, job.id, jobstore_alias, run_time,
-                                            traceback=formatted_tb))
+                                            exception=exc, traceback=formatted_tb))
             logger.exception('Job "%s" raised an exception', job)
+
+            # This is to prevent cyclic references that would lead to memory leaks
+            if six.PY2:
+                sys.exc_clear()
+                del tb
             else:
-            events.append(JobExecutionEvent(EVENT_JOB_EXECUTED, job.id, jobstore_alias, run_time, retval=retval))
+                import traceback
+                traceback.clear_frames(tb)
+                del tb
+        else:
+            events.append(JobExecutionEvent(EVENT_JOB_EXECUTED, job.id, jobstore_alias, run_time,
+                                            retval=retval))
             logger.info('Job "%s" executed successfully', job)
 
     return events

lib/apscheduler/executors/base_py3.py

@@ -0,0 +1,41 @@
+import logging
+import sys
+from datetime import datetime, timedelta
+from traceback import format_tb
+
+from pytz import utc
+
+from apscheduler.events import (
+    JobExecutionEvent, EVENT_JOB_MISSED, EVENT_JOB_ERROR, EVENT_JOB_EXECUTED)
+
+
+async def run_coroutine_job(job, jobstore_alias, run_times, logger_name):
+    """Coroutine version of run_job()."""
+    events = []
+    logger = logging.getLogger(logger_name)
+    for run_time in run_times:
+        # See if the job missed its run time window, and handle possible misfires accordingly
+        if job.misfire_grace_time is not None:
+            difference = datetime.now(utc) - run_time
+            grace_time = timedelta(seconds=job.misfire_grace_time)
+            if difference > grace_time:
+                events.append(JobExecutionEvent(EVENT_JOB_MISSED, job.id, jobstore_alias,
+                                                run_time))
+                logger.warning('Run time of job "%s" was missed by %s', job, difference)
+                continue
+
+        logger.info('Running job "%s" (scheduled at %s)', job, run_time)
+        try:
+            retval = await job.func(*job.args, **job.kwargs)
+        except BaseException:
+            exc, tb = sys.exc_info()[1:]
+            formatted_tb = ''.join(format_tb(tb))
+            events.append(JobExecutionEvent(EVENT_JOB_ERROR, job.id, jobstore_alias, run_time,
+                                            exception=exc, traceback=formatted_tb))
+            logger.exception('Job "%s" raised an exception', job)
+        else:
+            events.append(JobExecutionEvent(EVENT_JOB_EXECUTED, job.id, jobstore_alias, run_time,
+                                            retval=retval))
+            logger.info('Job "%s" executed successfully', job)
+
+    return events

lib/apscheduler/executors/debug.py

@@ -5,7 +5,8 @@ from apscheduler.executors.base import BaseExecutor, run_job
 
 class DebugExecutor(BaseExecutor):
     """
-    A special executor that executes the target callable directly instead of deferring it to a thread or process.
+    A special executor that executes the target callable directly instead of deferring it to a
+    thread or process.
 
     Plugin alias: ``debug``
     """
@@ -13,7 +14,7 @@ class DebugExecutor(BaseExecutor):
     def _do_submit_job(self, job, run_times):
         try:
             events = run_job(job, job._jobstore_alias, run_times, self._logger.name)
-        except:
+        except BaseException:
             self._run_job_error(job.id, *sys.exc_info()[1:])
         else:
             self._run_job_success(job.id, events)

lib/apscheduler/executors/gevent.py

@@ -21,9 +21,10 @@ class GeventExecutor(BaseExecutor):
         def callback(greenlet):
             try:
                 events = greenlet.get()
-            except:
+            except BaseException:
                 self._run_job_error(job.id, *sys.exc_info()[1:])
             else:
                 self._run_job_success(job.id, events)
 
-        gevent.spawn(run_job, job, job._jobstore_alias, run_times, self._logger.name).link(callback)
+        gevent.spawn(run_job, job, job._jobstore_alias, run_times, self._logger.name).\
+            link(callback)

lib/apscheduler/executors/tornado.py

@@ -0,0 +1,54 @@
+from __future__ import absolute_import
+
+import sys
+from concurrent.futures import ThreadPoolExecutor
+
+from tornado.gen import convert_yielded
+
+from apscheduler.executors.base import BaseExecutor, run_job
+
+try:
+    from inspect import iscoroutinefunction
+    from apscheduler.executors.base_py3 import run_coroutine_job
+except ImportError:
+    def iscoroutinefunction(func):
+        return False
+
+
+class TornadoExecutor(BaseExecutor):
+    """
+    Runs jobs either in a thread pool or directly on the I/O loop.
+
+    If the job function is a native coroutine function, it is scheduled to be run directly in the
+    I/O loop as soon as possible. All other functions are run in a thread pool.
+
+    Plugin alias: ``tornado``
+
+    :param int max_workers: maximum number of worker threads in the thread pool
+    """
+
+    def __init__(self, max_workers=10):
+        super(TornadoExecutor, self).__init__()
+        self.executor = ThreadPoolExecutor(max_workers)
+
+    def start(self, scheduler, alias):
+        super(TornadoExecutor, self).start(scheduler, alias)
+        self._ioloop = scheduler._ioloop
+
+    def _do_submit_job(self, job, run_times):
+        def callback(f):
+            try:
+                events = f.result()
+            except BaseException:
+                self._run_job_error(job.id, *sys.exc_info()[1:])
+            else:
+                self._run_job_success(job.id, events)
+
+        if iscoroutinefunction(job.func):
+            f = run_coroutine_job(job, job._jobstore_alias, run_times, self._logger.name)
+        else:
+            f = self.executor.submit(run_job, job, job._jobstore_alias, run_times,
+                                     self._logger.name)
+
+        f = convert_yielded(f)
+        f.add_done_callback(callback)

lib/apscheduler/executors/twisted.py

@@ -21,5 +21,5 @@ class TwistedExecutor(BaseExecutor):
             else:
                 self._run_job_error(job.id, result.value, result.tb)
 
-        self._reactor.getThreadPool().callInThreadWithCallback(callback, run_job, job, job._jobstore_alias, run_times,
+        self._reactor.getThreadPool().callInThreadWithCallback(
-                                                               self._logger.name)
+            callback, run_job, job, job._jobstore_alias, run_times, self._logger.name)

lib/apscheduler/job.py

@@ -4,8 +4,9 @@ from uuid import uuid4
 import six
 
 from apscheduler.triggers.base import BaseTrigger
-from apscheduler.util import ref_to_obj, obj_to_ref, datetime_repr, repr_escape, get_callable_name, check_callable_args, \
+from apscheduler.util import (
-    convert_to_datetime
+    ref_to_obj, obj_to_ref, datetime_repr, repr_escape, get_callable_name, check_callable_args,
+    convert_to_datetime)
 
 
 class Job(object):
@@ -21,13 +22,20 @@ class Job(object):
     :var bool coalesce: whether to only run the job once when several run times are due
     :var trigger: the trigger object that controls the schedule of this job
     :var str executor: the name of the executor that will run this job
-    :var int misfire_grace_time: the time (in seconds) how much this job's execution is allowed to be late
+    :var int misfire_grace_time: the time (in seconds) how much this job's execution is allowed to
-    :var int max_instances: the maximum number of concurrently executing instances allowed for this job
+        be late
+    :var int max_instances: the maximum number of concurrently executing instances allowed for this
+        job
     :var datetime.datetime next_run_time: the next scheduled run time of this job
+
+    .. note::
+        The ``misfire_grace_time`` has some non-obvious effects on job execution. See the
+        :ref:`missed-job-executions` section in the documentation for an in-depth explanation.
     """
 
-    __slots__ = ('_scheduler', '_jobstore_alias', 'id', 'trigger', 'executor', 'func', 'func_ref', 'args', 'kwargs',
+    __slots__ = ('_scheduler', '_jobstore_alias', 'id', 'trigger', 'executor', 'func', 'func_ref',
-                 'name', 'misfire_grace_time', 'coalesce', 'max_instances', 'next_run_time')
+                 'args', 'kwargs', 'name', 'misfire_grace_time', 'coalesce', 'max_instances',
+                 'next_run_time')
 
     def __init__(self, scheduler, id=None, **kwargs):
         super(Job, self).__init__()
@@ -38,53 +46,69 @@ class Job(object):
     def modify(self, **changes):
         """
         Makes the given changes to this job and saves it in the associated job store.
+
         Accepted keyword arguments are the same as the variables on this class.
 
         .. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.modify_job`
-        """
 
+        :return Job: this job instance
+
+        """
         self._scheduler.modify_job(self.id, self._jobstore_alias, **changes)
+        return self
 
     def reschedule(self, trigger, **trigger_args):
         """
         Shortcut for switching the trigger on this job.
 
         .. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.reschedule_job`
-        """
 
+        :return Job: this job instance
+
+        """
         self._scheduler.reschedule_job(self.id, self._jobstore_alias, trigger, **trigger_args)
+        return self
 
     def pause(self):
         """
         Temporarily suspend the execution of this job.
 
         .. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.pause_job`
-        """
 
+        :return Job: this job instance
+
+        """
         self._scheduler.pause_job(self.id, self._jobstore_alias)
+        return self
 
     def resume(self):
         """
         Resume the schedule of this job if previously paused.
 
         .. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.resume_job`
-        """
 
+        :return Job: this job instance
+
+        """
         self._scheduler.resume_job(self.id, self._jobstore_alias)
+        return self
 
     def remove(self):
         """
         Unschedules this job and removes it from its associated job store.
 
         .. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.remove_job`
-        """
 
+        """
         self._scheduler.remove_job(self.id, self._jobstore_alias)
 
     @property
     def pending(self):
-        """Returns ``True`` if the referenced job is still waiting to be added to its designated job store."""
+        """
+        Returns ``True`` if the referenced job is still waiting to be added to its designated job
+        store.
 
+        """
         return self._jobstore_alias is None
 
     #
@@ -97,8 +121,8 @@ class Job(object):
 
         :type now: datetime.datetime
         :rtype: list[datetime.datetime]
-        """
 
+        """
         run_times = []
         next_run_time = self.next_run_time
         while next_run_time and next_run_time <= now:
@@ -108,8 +132,11 @@ class Job(object):
         return run_times
 
     def _modify(self, **changes):
-        """Validates the changes to the Job and makes the modifications if and only if all of them validate."""
+        """
+        Validates the changes to the Job and makes the modifications if and only if all of them
+        validate.
 
+        """
         approved = {}
 
         if 'id' in changes:
@@ -125,7 +152,7 @@ class Job(object):
             args = changes.pop('args') if 'args' in changes else self.args
             kwargs = changes.pop('kwargs') if 'kwargs' in changes else self.kwargs
 
-            if isinstance(func, str):
+            if isinstance(func, six.string_types):
                 func_ref = func
                 func = ref_to_obj(func)
             elif callable(func):
@@ -177,7 +204,8 @@ class Job(object):
         if 'trigger' in changes:
             trigger = changes.pop('trigger')
             if not isinstance(trigger, BaseTrigger):
-                raise TypeError('Expected a trigger instance, got %s instead' % trigger.__class__.__name__)
+                raise TypeError('Expected a trigger instance, got %s instead' %
+                                trigger.__class__.__name__)
 
             approved['trigger'] = trigger
 
@@ -189,10 +217,12 @@ class Job(object):
 
         if 'next_run_time' in changes:
             value = changes.pop('next_run_time')
-            approved['next_run_time'] = convert_to_datetime(value, self._scheduler.timezone, 'next_run_time')
+            approved['next_run_time'] = convert_to_datetime(value, self._scheduler.timezone,
+                                                            'next_run_time')
 
         if changes:
-            raise AttributeError('The following are not modifiable attributes of Job: %s' % ', '.join(changes))
+            raise AttributeError('The following are not modifiable attributes of Job: %s' %
+                                 ', '.join(changes))
 
         for key, value in six.iteritems(approved):
             setattr(self, key, value)
@@ -200,9 +230,10 @@ class Job(object):
     def __getstate__(self):
         # Don't allow this Job to be serialized if the function reference could not be determined
         if not self.func_ref:
-            raise ValueError('This Job cannot be serialized since the reference to its callable (%r) could not be '
+            raise ValueError(
-                             'determined. Consider giving a textual reference (module:function name) instead.' %
+                'This Job cannot be serialized since the reference to its callable (%r) could not '
-                             (self.func,))
+                'be determined. Consider giving a textual reference (module:function name) '
+                'instead.' % (self.func,))
 
         return {
             'version': 1,
@@ -221,7 +252,8 @@ class Job(object):
 
     def __setstate__(self, state):
         if state.get('version', 1) > 1:
-            raise ValueError('Job has version %s, but only version 1 can be handled' % state['version'])
+            raise ValueError('Job has version %s, but only version 1 can be handled' %
+                             state['version'])
 
         self.id = state['id']
         self.func_ref = state['func']
@@ -245,8 +277,13 @@ class Job(object):
         return '<Job (id=%s name=%s)>' % (repr_escape(self.id), repr_escape(self.name))
 
     def __str__(self):
-        return '%s (trigger: %s, next run at: %s)' % (repr_escape(self.name), repr_escape(str(self.trigger)),
+        return repr_escape(self.__unicode__())
-                                                      datetime_repr(self.next_run_time))
 
     def __unicode__(self):
-        return six.u('%s (trigger: %s, next run at: %s)') % (self.name, self.trigger, datetime_repr(self.next_run_time))
+        if hasattr(self, 'next_run_time'):
+            status = ('next run at: ' + datetime_repr(self.next_run_time) if
+                      self.next_run_time else 'paused')
+        else:
+            status = 'pending'
+
+        return u'%s (trigger: %s, %s)' % (self.name, self.trigger, status)

lib/apscheduler/jobstores/base.py

@@ -8,23 +8,27 @@ class JobLookupError(KeyError):
     """Raised when the job store cannot find a job for update or removal."""
 
     def __init__(self, job_id):
-        super(JobLookupError, self).__init__(six.u('No job by the id of %s was found') % job_id)
+        super(JobLookupError, self).__init__(u'No job by the id of %s was found' % job_id)
 
 
 class ConflictingIdError(KeyError):
     """Raised when the uniqueness of job IDs is being violated."""
 
     def __init__(self, job_id):
-        super(ConflictingIdError, self).__init__(six.u('Job identifier (%s) conflicts with an existing job') % job_id)
+        super(ConflictingIdError, self).__init__(
+            u'Job identifier (%s) conflicts with an existing job' % job_id)
 
 
 class TransientJobError(ValueError):
-    """Raised when an attempt to add transient (with no func_ref) job to a persistent job store is detected."""
+    """
+    Raised when an attempt to add transient (with no func_ref) job to a persistent job store is
+    detected.
+    """
 
     def __init__(self, job_id):
         super(TransientJobError, self).__init__(
-            six.u('Job (%s) cannot be added to this job store because a reference to the callable could not be '
+            u'Job (%s) cannot be added to this job store because a reference to the callable '
-                  'determined.') % job_id)
+            u'could not be determined.' % job_id)
 
 
 class BaseJobStore(six.with_metaclass(ABCMeta)):
@@ -36,10 +40,11 @@ class BaseJobStore(six.with_metaclass(ABCMeta)):
 
     def start(self, scheduler, alias):
         """
-        Called by the scheduler when the scheduler is being started or when the job store is being added to an already
+        Called by the scheduler when the scheduler is being started or when the job store is being
-        running scheduler.
+        added to an already running scheduler.
 
-        :param apscheduler.schedulers.base.BaseScheduler scheduler: the scheduler that is starting this job store
+        :param apscheduler.schedulers.base.BaseScheduler scheduler: the scheduler that is starting
+            this job store
         :param str|unicode alias: alias of this job store as it was assigned to the scheduler
         """
 
@@ -50,13 +55,22 @@ class BaseJobStore(six.with_metaclass(ABCMeta)):
     def shutdown(self):
         """Frees any resources still bound to this job store."""
 
+    def _fix_paused_jobs_sorting(self, jobs):
+        for i, job in enumerate(jobs):
+            if job.next_run_time is not None:
+                if i > 0:
+                    paused_jobs = jobs[:i]
+                    del jobs[:i]
+                    jobs.extend(paused_jobs)
+                break
+
     @abstractmethod
     def lookup_job(self, job_id):
         """
         Returns a specific job, or ``None`` if it isn't found..
 
-        The job store is responsible for setting the ``scheduler`` and ``jobstore`` attributes of the returned job to
+        The job store is responsible for setting the ``scheduler`` and ``jobstore`` attributes of
-        point to the scheduler and itself, respectively.
+        the returned job to point to the scheduler and itself, respectively.
 
         :param str|unicode job_id: identifier of the job
         :rtype: Job
@@ -75,7 +89,8 @@ class BaseJobStore(six.with_metaclass(ABCMeta)):
     @abstractmethod
     def get_next_run_time(self):
         """
-        Returns the earliest run time of all the jobs stored in this job store, or ``None`` if there are no active jobs.
+        Returns the earliest run time of all the jobs stored in this job store, or ``None`` if
+        there are no active jobs.
 
         :rtype: datetime.datetime
         """
@@ -83,11 +98,12 @@ class BaseJobStore(six.with_metaclass(ABCMeta)):
     @abstractmethod
     def get_all_jobs(self):
         """
-        Returns a list of all jobs in this job store. The returned jobs should be sorted by next run time (ascending).
+        Returns a list of all jobs in this job store.
-        Paused jobs (next_run_time is None) should be sorted last.
+        The returned jobs should be sorted by next run time (ascending).
+        Paused jobs (next_run_time == None) should be sorted last.
 
-        The job store is responsible for setting the ``scheduler`` and ``jobstore`` attributes of the returned jobs to
+        The job store is responsible for setting the ``scheduler`` and ``jobstore`` attributes of
-        point to the scheduler and itself, respectively.
+        the returned jobs to point to the scheduler and itself, respectively.
 
         :rtype: list[Job]
         """

lib/apscheduler/jobstores/memory.py

@@ -13,7 +13,8 @@ class MemoryJobStore(BaseJobStore):
 
     def __init__(self):
         super(MemoryJobStore, self).__init__()
-        self._jobs = []  # list of (job, timestamp), sorted by next_run_time and job id (ascending)
+        # list of (job, timestamp), sorted by next_run_time and job id (ascending)
+        self._jobs = []
         self._jobs_index = {}  # id -> (job, timestamp) lookup table
 
     def lookup_job(self, job_id):
@@ -80,13 +81,13 @@ class MemoryJobStore(BaseJobStore):
 
     def _get_job_index(self, timestamp, job_id):
         """
-        Returns the index of the given job, or if it's not found, the index where the job should be inserted based on
+        Returns the index of the given job, or if it's not found, the index where the job should be
-        the given timestamp.
+        inserted based on the given timestamp.
 
         :type timestamp: int
         :type job_id: str
-        """
 
+        """
         lo, hi = 0, len(self._jobs)
         timestamp = float('inf') if timestamp is None else timestamp
         while lo < hi:

lib/apscheduler/jobstores/mongodb.py

@@ -1,4 +1,5 @@
 from __future__ import absolute_import
+import warnings
 
 from apscheduler.jobstores.base import BaseJobStore, JobLookupError, ConflictingIdError
 from apscheduler.util import maybe_ref, datetime_to_utc_timestamp, utc_timestamp_to_datetime
@@ -19,16 +20,18 @@ except ImportError:  # pragma: nocover
 
 class MongoDBJobStore(BaseJobStore):
     """
-    Stores jobs in a MongoDB database. Any leftover keyword arguments are directly passed to pymongo's `MongoClient
+    Stores jobs in a MongoDB database. Any leftover keyword arguments are directly passed to
+    pymongo's `MongoClient
     <http://api.mongodb.org/python/current/api/pymongo/mongo_client.html#pymongo.mongo_client.MongoClient>`_.
 
     Plugin alias: ``mongodb``
 
     :param str database: database to store jobs in
     :param str collection: collection to store jobs in
-    :param client: a :class:`~pymongo.mongo_client.MongoClient` instance to use instead of providing connection
+    :param client: a :class:`~pymongo.mongo_client.MongoClient` instance to use instead of
-                   arguments
+        providing connection arguments
-    :param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the highest available
+    :param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the
+        highest available
     """
 
     def __init__(self, database='apscheduler', collection='jobs', client=None,
@@ -42,14 +45,23 @@ class MongoDBJobStore(BaseJobStore):
             raise ValueError('The "collection" parameter must not be empty')
 
         if client:
-            self.connection = maybe_ref(client)
+            self.client = maybe_ref(client)
         else:
             connect_args.setdefault('w', 1)
-            self.connection = MongoClient(**connect_args)
+            self.client = MongoClient(**connect_args)
 
-        self.collection = self.connection[database][collection]
+        self.collection = self.client[database][collection]
+
+    def start(self, scheduler, alias):
+        super(MongoDBJobStore, self).start(scheduler, alias)
         self.collection.ensure_index('next_run_time', sparse=True)
 
+    @property
+    def connection(self):
+        warnings.warn('The "connection" member is deprecated -- use "client" instead',
+                      DeprecationWarning)
+        return self.client
+
     def lookup_job(self, job_id):
         document = self.collection.find_one(job_id, ['job_state'])
         return self._reconstitute_job(document['job_state']) if document else None
@@ -59,12 +71,15 @@ class MongoDBJobStore(BaseJobStore):
         return self._get_jobs({'next_run_time': {'$lte': timestamp}})
 
     def get_next_run_time(self):
-        document = self.collection.find_one({'next_run_time': {'$ne': None}}, fields=['next_run_time'],
+        document = self.collection.find_one({'next_run_time': {'$ne': None}},
+                                            projection=['next_run_time'],
                                             sort=[('next_run_time', ASCENDING)])
         return utc_timestamp_to_datetime(document['next_run_time']) if document else None
 
     def get_all_jobs(self):
-        return self._get_jobs({})
+        jobs = self._get_jobs({})
+        self._fix_paused_jobs_sorting(jobs)
+        return jobs
 
     def add_job(self, job):
         try:
@@ -83,7 +98,7 @@ class MongoDBJobStore(BaseJobStore):
         }
         result = self.collection.update({'_id': job.id}, {'$set': changes})
         if result and result['n'] == 0:
-            raise JobLookupError(id)
+            raise JobLookupError(job.id)
 
     def remove_job(self, job_id):
         result = self.collection.remove(job_id)
@@ -94,7 +109,7 @@ class MongoDBJobStore(BaseJobStore):
         self.collection.remove()
 
     def shutdown(self):
-        self.connection.disconnect()
+        self.client.close()
 
     def _reconstitute_job(self, job_state):
         job_state = pickle.loads(job_state)
@@ -107,11 +122,13 @@ class MongoDBJobStore(BaseJobStore):
     def _get_jobs(self, conditions):
         jobs = []
         failed_job_ids = []
-        for document in self.collection.find(conditions, ['_id', 'job_state'], sort=[('next_run_time', ASCENDING)]):
+        for document in self.collection.find(conditions, ['_id', 'job_state'],
+                                             sort=[('next_run_time', ASCENDING)]):
             try:
                 jobs.append(self._reconstitute_job(document['job_state']))
-            except:
+            except BaseException:
-                self._logger.exception('Unable to restore job "%s" -- removing it', document['_id'])
+                self._logger.exception('Unable to restore job "%s" -- removing it',
+                                       document['_id'])
                 failed_job_ids.append(document['_id'])
 
         # Remove all the jobs we failed to restore
@@ -121,4 +138,4 @@ class MongoDBJobStore(BaseJobStore):
         return jobs
 
     def __repr__(self):
-        return '<%s (client=%s)>' % (self.__class__.__name__, self.connection)
+        return '<%s (client=%s)>' % (self.__class__.__name__, self.client)

lib/apscheduler/jobstores/redis.py

@@ -1,5 +1,7 @@
 from __future__ import absolute_import
+from datetime import datetime
 
+from pytz import utc
 import six
 
 from apscheduler.jobstores.base import BaseJobStore, JobLookupError, ConflictingIdError
@@ -19,14 +21,16 @@ except ImportError:  # pragma: nocover
 
 class RedisJobStore(BaseJobStore):
     """
-    Stores jobs in a Redis database. Any leftover keyword arguments are directly passed to redis's StrictRedis.
+    Stores jobs in a Redis database. Any leftover keyword arguments are directly passed to redis's
+    :class:`~redis.StrictRedis`.
 
     Plugin alias: ``redis``
 
     :param int db: the database number to store jobs in
     :param str jobs_key: key to store jobs in
     :param str run_times_key: key to store the jobs' run times in
-    :param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the highest available
+    :param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the
+        highest available
     """
 
     def __init__(self, db=0, jobs_key='apscheduler.jobs', run_times_key='apscheduler.run_times',
@@ -65,7 +69,8 @@ class RedisJobStore(BaseJobStore):
     def get_all_jobs(self):
         job_states = self.redis.hgetall(self.jobs_key)
         jobs = self._reconstitute_jobs(six.iteritems(job_states))
-        return sorted(jobs, key=lambda job: job.next_run_time)
+        paused_sort_key = datetime(9999, 12, 31, tzinfo=utc)
+        return sorted(jobs, key=lambda job: job.next_run_time or paused_sort_key)
 
     def add_job(self, job):
         if self.redis.hexists(self.jobs_key, job.id):
@@ -73,7 +78,9 @@ class RedisJobStore(BaseJobStore):
 
         with self.redis.pipeline() as pipe:
             pipe.multi()
-            pipe.hset(self.jobs_key, job.id, pickle.dumps(job.__getstate__(), self.pickle_protocol))
+            pipe.hset(self.jobs_key, job.id, pickle.dumps(job.__getstate__(),
+                                                          self.pickle_protocol))
+            if job.next_run_time:
                 pipe.zadd(self.run_times_key, datetime_to_utc_timestamp(job.next_run_time), job.id)
             pipe.execute()
 
@@ -82,7 +89,8 @@ class RedisJobStore(BaseJobStore):
             raise JobLookupError(job.id)
 
         with self.redis.pipeline() as pipe:
-            pipe.hset(self.jobs_key, job.id, pickle.dumps(job.__getstate__(), self.pickle_protocol))
+            pipe.hset(self.jobs_key, job.id, pickle.dumps(job.__getstate__(),
+                                                          self.pickle_protocol))
             if job.next_run_time:
                 pipe.zadd(self.run_times_key, datetime_to_utc_timestamp(job.next_run_time), job.id)
             else:
@@ -121,7 +129,7 @@ class RedisJobStore(BaseJobStore):
         for job_id, job_state in job_states:
             try:
                 jobs.append(self._reconstitute_job(job_state))
-            except:
+            except BaseException:
                 self._logger.exception('Unable to restore job "%s" -- removing it', job_id)
                 failed_job_ids.append(job_id)
 

lib/apscheduler/jobstores/rethinkdb.py

@@ -0,0 +1,153 @@
+from __future__ import absolute_import
+
+from apscheduler.jobstores.base import BaseJobStore, JobLookupError, ConflictingIdError
+from apscheduler.util import maybe_ref, datetime_to_utc_timestamp, utc_timestamp_to_datetime
+from apscheduler.job import Job
+
+try:
+    import cPickle as pickle
+except ImportError:  # pragma: nocover
+    import pickle
+
+try:
+    import rethinkdb as r
+except ImportError:  # pragma: nocover
+    raise ImportError('RethinkDBJobStore requires rethinkdb installed')
+
+
+class RethinkDBJobStore(BaseJobStore):
+    """
+    Stores jobs in a RethinkDB database. Any leftover keyword arguments are directly passed to
+    rethinkdb's `RethinkdbClient <http://www.rethinkdb.com/api/#connect>`_.
+
+    Plugin alias: ``rethinkdb``
+
+    :param str database: database to store jobs in
+    :param str collection: collection to store jobs in
+    :param client: a :class:`rethinkdb.net.Connection` instance to use instead of providing
+        connection arguments
+    :param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the
+        highest available
+    """
+
+    def __init__(self, database='apscheduler', table='jobs', client=None,
+                 pickle_protocol=pickle.HIGHEST_PROTOCOL, **connect_args):
+        super(RethinkDBJobStore, self).__init__()
+
+        if not database:
+            raise ValueError('The "database" parameter must not be empty')
+        if not table:
+            raise ValueError('The "table" parameter must not be empty')
+
+        self.database = database
+        self.table = table
+        self.client = client
+        self.pickle_protocol = pickle_protocol
+        self.connect_args = connect_args
+        self.conn = None
+
+    def start(self, scheduler, alias):
+        super(RethinkDBJobStore, self).start(scheduler, alias)
+
+        if self.client:
+            self.conn = maybe_ref(self.client)
+        else:
+            self.conn = r.connect(db=self.database, **self.connect_args)
+
+        if self.database not in r.db_list().run(self.conn):
+            r.db_create(self.database).run(self.conn)
+
+        if self.table not in r.table_list().run(self.conn):
+            r.table_create(self.table).run(self.conn)
+
+        if 'next_run_time' not in r.table(self.table).index_list().run(self.conn):
+            r.table(self.table).index_create('next_run_time').run(self.conn)
+
+        self.table = r.db(self.database).table(self.table)
+
+    def lookup_job(self, job_id):
+        results = list(self.table.get_all(job_id).pluck('job_state').run(self.conn))
+        return self._reconstitute_job(results[0]['job_state']) if results else None
+
+    def get_due_jobs(self, now):
+        return self._get_jobs(r.row['next_run_time'] <= datetime_to_utc_timestamp(now))
+
+    def get_next_run_time(self):
+        results = list(
+            self.table
+            .filter(r.row['next_run_time'] != None)  # flake8: noqa
+            .order_by(r.asc('next_run_time'))
+            .map(lambda x: x['next_run_time'])
+            .limit(1)
+            .run(self.conn)
+        )
+        return utc_timestamp_to_datetime(results[0]) if results else None
+
+    def get_all_jobs(self):
+        jobs = self._get_jobs()
+        self._fix_paused_jobs_sorting(jobs)
+        return jobs
+
+    def add_job(self, job):
+        job_dict = {
+            'id': job.id,
+            'next_run_time': datetime_to_utc_timestamp(job.next_run_time),
+            'job_state': r.binary(pickle.dumps(job.__getstate__(), self.pickle_protocol))
+        }
+        results = self.table.insert(job_dict).run(self.conn)
+        if results['errors'] > 0:
+            raise ConflictingIdError(job.id)
+
+    def update_job(self, job):
+        changes = {
+            'next_run_time': datetime_to_utc_timestamp(job.next_run_time),
+            'job_state': r.binary(pickle.dumps(job.__getstate__(), self.pickle_protocol))
+        }
+        results = self.table.get_all(job.id).update(changes).run(self.conn)
+        skipped = False in map(lambda x: results[x] == 0, results.keys())
+        if results['skipped'] > 0 or results['errors'] > 0 or not skipped:
+            raise JobLookupError(job.id)
+
+    def remove_job(self, job_id):
+        results = self.table.get_all(job_id).delete().run(self.conn)
+        if results['deleted'] + results['skipped'] != 1:
+            raise JobLookupError(job_id)
+
+    def remove_all_jobs(self):
+        self.table.delete().run(self.conn)
+
+    def shutdown(self):
+        self.conn.close()
+
+    def _reconstitute_job(self, job_state):
+        job_state = pickle.loads(job_state)
+        job = Job.__new__(Job)
+        job.__setstate__(job_state)
+        job._scheduler = self._scheduler
+        job._jobstore_alias = self._alias
+        return job
+
+    def _get_jobs(self, predicate=None):
+        jobs = []
+        failed_job_ids = []
+        query = (self.table.filter(r.row['next_run_time'] != None).filter(predicate) if
+                 predicate else self.table)
+        query = query.order_by('next_run_time', 'id').pluck('id', 'job_state')
+
+        for document in query.run(self.conn):
+            try:
+                jobs.append(self._reconstitute_job(document['job_state']))
+            except:
+                self._logger.exception('Unable to restore job "%s" -- removing it', document['id'])
+                failed_job_ids.append(document['id'])
+
+        # Remove all the jobs we failed to restore
+        if failed_job_ids:
+            r.expr(failed_job_ids).for_each(
+                lambda job_id: self.table.get_all(job_id).delete()).run(self.conn)
+
+        return jobs
+
+    def __repr__(self):
+        connection = self.conn
+        return '<%s (connection=%s)>' % (self.__class__.__name__, connection)

lib/apscheduler/jobstores/sqlalchemy.py

@@ -10,29 +10,38 @@ except ImportError:  # pragma: nocover
     import pickle
 
 try:
-    from sqlalchemy import create_engine, Table, Column, MetaData, Unicode, Float, LargeBinary, select
+    from sqlalchemy import (
+        create_engine, Table, Column, MetaData, Unicode, Float, LargeBinary, select)
     from sqlalchemy.exc import IntegrityError
+    from sqlalchemy.sql.expression import null
 except ImportError:  # pragma: nocover
     raise ImportError('SQLAlchemyJobStore requires SQLAlchemy installed')
 
 
 class SQLAlchemyJobStore(BaseJobStore):
     """
-    Stores jobs in a database table using SQLAlchemy. The table will be created if it doesn't exist in the database.
+    Stores jobs in a database table using SQLAlchemy.
+    The table will be created if it doesn't exist in the database.
 
     Plugin alias: ``sqlalchemy``
 
-    :param str url: connection string (see `SQLAlchemy documentation
+    :param str url: connection string (see
-                    <http://docs.sqlalchemy.org/en/latest/core/engines.html?highlight=create_engine#database-urls>`_
+        :ref:`SQLAlchemy documentation <sqlalchemy:database_urls>` on this)
-                    on this)
+    :param engine: an SQLAlchemy :class:`~sqlalchemy.engine.Engine` to use instead of creating a
-    :param engine: an SQLAlchemy Engine to use instead of creating a new one based on ``url``
+        new one based on ``url``
     :param str tablename: name of the table to store jobs in
-    :param metadata: a :class:`~sqlalchemy.MetaData` instance to use instead of creating a new one
+    :param metadata: a :class:`~sqlalchemy.schema.MetaData` instance to use instead of creating a
-    :param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the highest available
+        new one
+    :param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the
+        highest available
+    :param str tableschema: name of the (existing) schema in the target database where the table
+        should be
+    :param dict engine_options: keyword arguments to :func:`~sqlalchemy.create_engine`
+        (ignored if ``engine`` is given)
     """
 
     def __init__(self, url=None, engine=None, tablename='apscheduler_jobs', metadata=None,
-                 pickle_protocol=pickle.HIGHEST_PROTOCOL):
+                 pickle_protocol=pickle.HIGHEST_PROTOCOL, tableschema=None, engine_options=None):
         super(SQLAlchemyJobStore, self).__init__()
         self.pickle_protocol = pickle_protocol
         metadata = maybe_ref(metadata) or MetaData()
@@ -40,18 +49,22 @@ class SQLAlchemyJobStore(BaseJobStore):
         if engine:
             self.engine = maybe_ref(engine)
         elif url:
-            self.engine = create_engine(url)
+            self.engine = create_engine(url, **(engine_options or {}))
         else:
             raise ValueError('Need either "engine" or "url" defined')
 
-        # 191 = max key length in MySQL for InnoDB/utf8mb4 tables, 25 = precision that translates to an 8-byte float
+        # 191 = max key length in MySQL for InnoDB/utf8mb4 tables,
+        # 25 = precision that translates to an 8-byte float
         self.jobs_t = Table(
             tablename, metadata,
             Column('id', Unicode(191, _warn_on_bytestring=False), primary_key=True),
             Column('next_run_time', Float(25), index=True),
-            Column('job_state', LargeBinary, nullable=False)
+            Column('job_state', LargeBinary, nullable=False),
+            schema=tableschema
         )
 
+    def start(self, scheduler, alias):
+        super(SQLAlchemyJobStore, self).start(scheduler, alias)
         self.jobs_t.create(self.engine, True)
 
     def lookup_job(self, job_id):
@@ -64,13 +77,16 @@ class SQLAlchemyJobStore(BaseJobStore):
         return self._get_jobs(self.jobs_t.c.next_run_time <= timestamp)
 
     def get_next_run_time(self):
-        selectable = select([self.jobs_t.c.next_run_time]).where(self.jobs_t.c.next_run_time != None).\
+        selectable = select([self.jobs_t.c.next_run_time]).\
+            where(self.jobs_t.c.next_run_time != null()).\
             order_by(self.jobs_t.c.next_run_time).limit(1)
         next_run_time = self.engine.execute(selectable).scalar()
         return utc_timestamp_to_datetime(next_run_time)
 
     def get_all_jobs(self):
-        return self._get_jobs()
+        jobs = self._get_jobs()
+        self._fix_paused_jobs_sorting(jobs)
+        return jobs
 
     def add_job(self, job):
         insert = self.jobs_t.insert().values(**{
@@ -116,13 +132,14 @@ class SQLAlchemyJobStore(BaseJobStore):
 
     def _get_jobs(self, *conditions):
         jobs = []
-        selectable = select([self.jobs_t.c.id, self.jobs_t.c.job_state]).order_by(self.jobs_t.c.next_run_time)
+        selectable = select([self.jobs_t.c.id, self.jobs_t.c.job_state]).\
+            order_by(self.jobs_t.c.next_run_time)
         selectable = selectable.where(*conditions) if conditions else selectable
         failed_job_ids = set()
         for row in self.engine.execute(selectable):
             try:
                 jobs.append(self._reconstitute_job(row.job_state))
-            except:
+            except BaseException:
                 self._logger.exception('Unable to restore job "%s" -- removing it', row.id)
                 failed_job_ids.add(row.id)
 

lib/apscheduler/jobstores/zookeeper.py

@@ -0,0 +1,179 @@
+from __future__ import absolute_import
+
+import os
+from datetime import datetime
+
+from pytz import utc
+from kazoo.exceptions import NoNodeError, NodeExistsError
+
+from apscheduler.jobstores.base import BaseJobStore, JobLookupError, ConflictingIdError
+from apscheduler.util import maybe_ref, datetime_to_utc_timestamp, utc_timestamp_to_datetime
+from apscheduler.job import Job
+
+try:
+    import cPickle as pickle
+except ImportError:  # pragma: nocover
+    import pickle
+
+try:
+    from kazoo.client import KazooClient
+except ImportError:  # pragma: nocover
+    raise ImportError('ZooKeeperJobStore requires Kazoo installed')
+
+
+class ZooKeeperJobStore(BaseJobStore):
+    """
+    Stores jobs in a ZooKeeper tree. Any leftover keyword arguments are directly passed to
+    kazoo's `KazooClient
+    <http://kazoo.readthedocs.io/en/latest/api/client.html>`_.
+
+    Plugin alias: ``zookeeper``
+
+    :param str path: path to store jobs in
+    :param client: a :class:`~kazoo.client.KazooClient` instance to use instead of
+        providing connection arguments
+    :param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the
+        highest available
+    """
+
+    def __init__(self, path='/apscheduler', client=None, close_connection_on_exit=False,
+                 pickle_protocol=pickle.HIGHEST_PROTOCOL, **connect_args):
+        super(ZooKeeperJobStore, self).__init__()
+        self.pickle_protocol = pickle_protocol
+        self.close_connection_on_exit = close_connection_on_exit
+
+        if not path:
+            raise ValueError('The "path" parameter must not be empty')
+
+        self.path = path
+
+        if client:
+            self.client = maybe_ref(client)
+        else:
+            self.client = KazooClient(**connect_args)
+        self._ensured_path = False
+
+    def _ensure_paths(self):
+        if not self._ensured_path:
+            self.client.ensure_path(self.path)
+        self._ensured_path = True
+
+    def start(self, scheduler, alias):
+        super(ZooKeeperJobStore, self).start(scheduler, alias)
+        if not self.client.connected:
+            self.client.start()
+
+    def lookup_job(self, job_id):
+        self._ensure_paths()
+        node_path = os.path.join(self.path, job_id)
+        try:
+            content, _ = self.client.get(node_path)
+            doc = pickle.loads(content)
+            job = self._reconstitute_job(doc['job_state'])
+            return job
+        except BaseException:
+            return None
+
+    def get_due_jobs(self, now):
+        timestamp = datetime_to_utc_timestamp(now)
+        jobs = [job_def['job'] for job_def in self._get_jobs()
+                if job_def['next_run_time'] is not None and job_def['next_run_time'] <= timestamp]
+        return jobs
+
+    def get_next_run_time(self):
+        next_runs = [job_def['next_run_time'] for job_def in self._get_jobs()
+                     if job_def['next_run_time'] is not None]
+        return utc_timestamp_to_datetime(min(next_runs)) if len(next_runs) > 0 else None
+
+    def get_all_jobs(self):
+        jobs = [job_def['job'] for job_def in self._get_jobs()]
+        self._fix_paused_jobs_sorting(jobs)
+        return jobs
+
+    def add_job(self, job):
+        self._ensure_paths()
+        node_path = os.path.join(self.path,  str(job.id))
+        value = {
+            'next_run_time': datetime_to_utc_timestamp(job.next_run_time),
+            'job_state': job.__getstate__()
+        }
+        data = pickle.dumps(value, self.pickle_protocol)
+        try:
+            self.client.create(node_path, value=data)
+        except NodeExistsError:
+            raise ConflictingIdError(job.id)
+
+    def update_job(self, job):
+        self._ensure_paths()
+        node_path = os.path.join(self.path,  str(job.id))
+        changes = {
+            'next_run_time': datetime_to_utc_timestamp(job.next_run_time),
+            'job_state': job.__getstate__()
+        }
+        data = pickle.dumps(changes, self.pickle_protocol)
+        try:
+            self.client.set(node_path, value=data)
+        except NoNodeError:
+            raise JobLookupError(job.id)
+
+    def remove_job(self, job_id):
+        self._ensure_paths()
+        node_path = os.path.join(self.path,  str(job_id))
+        try:
+            self.client.delete(node_path)
+        except NoNodeError:
+            raise JobLookupError(job_id)
+
+    def remove_all_jobs(self):
+        try:
+            self.client.delete(self.path, recursive=True)
+        except NoNodeError:
+            pass
+        self._ensured_path = False
+
+    def shutdown(self):
+        if self.close_connection_on_exit:
+            self.client.stop()
+            self.client.close()
+
+    def _reconstitute_job(self, job_state):
+        job_state = job_state
+        job = Job.__new__(Job)
+        job.__setstate__(job_state)
+        job._scheduler = self._scheduler
+        job._jobstore_alias = self._alias
+        return job
+
+    def _get_jobs(self):
+        self._ensure_paths()
+        jobs = []
+        failed_job_ids = []
+        all_ids = self.client.get_children(self.path)
+        for node_name in all_ids:
+            try:
+                node_path = os.path.join(self.path, node_name)
+                content, _ = self.client.get(node_path)
+                doc = pickle.loads(content)
+                job_def = {
+                    'job_id': node_name,
+                    'next_run_time': doc['next_run_time'] if doc['next_run_time'] else None,
+                    'job_state': doc['job_state'],
+                    'job': self._reconstitute_job(doc['job_state']),
+                    'creation_time': _.ctime
+                }
+                jobs.append(job_def)
+            except BaseException:
+                self._logger.exception('Unable to restore job "%s" -- removing it' % node_name)
+                failed_job_ids.append(node_name)
+
+        # Remove all the jobs we failed to restore
+        if failed_job_ids:
+            for failed_id in failed_job_ids:
+                self.remove_job(failed_id)
+        paused_sort_key = datetime(9999, 12, 31, tzinfo=utc)
+        return sorted(jobs, key=lambda job_def: (job_def['job'].next_run_time or paused_sort_key,
+                                                 job_def['creation_time']))
+
+    def __repr__(self):
+        self._logger.exception('<%s (client=%s)>' % (self.__class__.__name__, self.client))
+        return '<%s (client=%s)>' % (self.__class__.__name__, self.client)

lib/apscheduler/schedulers/asyncio.py

@@ -1,5 +1,5 @@
 from __future__ import absolute_import
-from functools import wraps
+from functools import wraps, partial
 
 from apscheduler.schedulers.base import BaseScheduler
 from apscheduler.util import maybe_ref
@@ -10,13 +10,15 @@ except ImportError:  # pragma: nocover
     try:
         import trollius as asyncio
     except ImportError:
-        raise ImportError('AsyncIOScheduler requires either Python 3.4 or the asyncio package installed')
+        raise ImportError(
+            'AsyncIOScheduler requires either Python 3.4 or the asyncio package installed')
 
 
 def run_in_event_loop(func):
     @wraps(func)
     def wrapper(self, *args, **kwargs):
-        self._eventloop.call_soon_threadsafe(func, self, *args, **kwargs)
+        wrapped = partial(func, self, *args, **kwargs)
+        self._eventloop.call_soon_threadsafe(wrapped)
     return wrapper
 
 
@@ -24,6 +26,8 @@ class AsyncIOScheduler(BaseScheduler):
     """
     A scheduler that runs on an asyncio (:pep:`3156`) event loop.
 
+    The default executor can run jobs based on native coroutines (``async def``).
+
     Extra options:
 
     ============== =============================================================
@@ -34,10 +38,6 @@ class AsyncIOScheduler(BaseScheduler):
     _eventloop = None
     _timeout = None
 
-    def start(self):
-        super(AsyncIOScheduler, self).start()
-        self.wakeup()
-
     @run_in_event_loop
     def shutdown(self, wait=True):
         super(AsyncIOScheduler, self).shutdown(wait)

lib/apscheduler/schedulers/background.py

@@ -1,4 +1,5 @@
 from __future__ import absolute_import
+
 from threading import Thread, Event
 
 from apscheduler.schedulers.base import BaseScheduler
@@ -13,11 +14,12 @@ class BackgroundScheduler(BlockingScheduler):
 
     Extra options:
 
-    ========== ============================================================================================
+    ========== =============================================================================
-    ``daemon`` Set the ``daemon`` option in the background thread (defaults to ``True``,
+    ``daemon`` Set the ``daemon`` option in the background thread (defaults to ``True``, see
-               see `the documentation <https://docs.python.org/3.4/library/threading.html#thread-objects>`_
+               `the documentation
+               <https://docs.python.org/3.4/library/threading.html#thread-objects>`_
                for further details)
-    ========== ============================================================================================
+    ========== =============================================================================
     """
 
     _thread = None
@@ -26,14 +28,14 @@ class BackgroundScheduler(BlockingScheduler):
         self._daemon = asbool(config.pop('daemon', True))
         super(BackgroundScheduler, self)._configure(config)
 
-    def start(self):
+    def start(self, *args, **kwargs):
-        BaseScheduler.start(self)
         self._event = Event()
+        BaseScheduler.start(self, *args, **kwargs)
         self._thread = Thread(target=self._main_loop, name='APScheduler')
         self._thread.daemon = self._daemon
         self._thread.start()
 
-    def shutdown(self, wait=True):
+    def shutdown(self, *args, **kwargs):
-        super(BackgroundScheduler, self).shutdown(wait)
+        super(BackgroundScheduler, self).shutdown(*args, **kwargs)
         self._thread.join()
         del self._thread

lib/apscheduler/schedulers/base.py

@@ -1,9 +1,11 @@
 from __future__ import print_function
+
 from abc import ABCMeta, abstractmethod
 from collections import MutableMapping
 from threading import RLock
-from datetime import datetime
+from datetime import datetime, timedelta
 from logging import getLogger
+import warnings
 import sys
 
 from pkg_resources import iter_entry_points
@@ -19,20 +21,39 @@ from apscheduler.job import Job
 from apscheduler.triggers.base import BaseTrigger
 from apscheduler.util import asbool, asint, astimezone, maybe_ref, timedelta_seconds, undefined
 from apscheduler.events import (
-    SchedulerEvent, JobEvent, EVENT_SCHEDULER_START, EVENT_SCHEDULER_SHUTDOWN, EVENT_JOBSTORE_ADDED,
+    SchedulerEvent, JobEvent, JobSubmissionEvent, EVENT_SCHEDULER_START, EVENT_SCHEDULER_SHUTDOWN,
-    EVENT_JOBSTORE_REMOVED, EVENT_ALL, EVENT_JOB_MODIFIED, EVENT_JOB_REMOVED, EVENT_JOB_ADDED, EVENT_EXECUTOR_ADDED,
+    EVENT_JOBSTORE_ADDED, EVENT_JOBSTORE_REMOVED, EVENT_ALL, EVENT_JOB_MODIFIED, EVENT_JOB_REMOVED,
-    EVENT_EXECUTOR_REMOVED, EVENT_ALL_JOBS_REMOVED)
+    EVENT_JOB_ADDED, EVENT_EXECUTOR_ADDED, EVENT_EXECUTOR_REMOVED, EVENT_ALL_JOBS_REMOVED,
+    EVENT_JOB_SUBMITTED, EVENT_JOB_MAX_INSTANCES, EVENT_SCHEDULER_RESUMED, EVENT_SCHEDULER_PAUSED)
+
+#: constant indicating a scheduler's stopped state
+STATE_STOPPED = 0
+#: constant indicating a scheduler's running state (started and processing jobs)
+STATE_RUNNING = 1
+#: constant indicating a scheduler's paused state (started but not processing jobs)
+STATE_PAUSED = 2
 
 
 class BaseScheduler(six.with_metaclass(ABCMeta)):
     """
-    Abstract base class for all schedulers. Takes the following keyword arguments:
+    Abstract base class for all schedulers.
 
-    :param str|logging.Logger logger: logger to use for the scheduler's logging (defaults to apscheduler.scheduler)
+    Takes the following keyword arguments:
+
+    :param str|logging.Logger logger: logger to use for the scheduler's logging (defaults to
+        apscheduler.scheduler)
     :param str|datetime.tzinfo timezone: the default time zone (defaults to the local timezone)
+    :param int|float jobstore_retry_interval: the minimum number of seconds to wait between
+        retries in the scheduler's main loop if the job store raises an exception when getting
+        the list of due jobs
     :param dict job_defaults: default values for newly added jobs
-    :param dict jobstores: a dictionary of job store alias -> job store instance or configuration dict
+    :param dict jobstores: a dictionary of job store alias -> job store instance or configuration
-    :param dict executors: a dictionary of executor alias -> executor instance or configuration dict
+        dict
+    :param dict executors: a dictionary of executor alias -> executor instance or configuration
+        dict
+
+    :ivar int state: current running state of the scheduler (one of the following constants from
+        ``apscheduler.schedulers.base``: ``STATE_STOPPED``, ``STATE_RUNNING``, ``STATE_PAUSED``)
 
     .. seealso:: :ref:`scheduler-config`
     """
@@ -43,7 +64,6 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
     _executor_classes = {}
     _jobstore_plugins = dict((ep.name, ep) for ep in iter_entry_points('apscheduler.jobstores'))
     _jobstore_classes = {}
-    _stopped = True
 
     #
     # Public API
@@ -58,28 +78,34 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         self._listeners = []
         self._listeners_lock = self._create_lock()
         self._pending_jobs = []
+        self.state = STATE_STOPPED
         self.configure(gconfig, **options)
 
     def configure(self, gconfig={}, prefix='apscheduler.', **options):
         """
-        Reconfigures the scheduler with the given options. Can only be done when the scheduler isn't running.
+        Reconfigures the scheduler with the given options.
 
-        :param dict gconfig: a "global" configuration dictionary whose values can be overridden by keyword arguments to
+        Can only be done when the scheduler isn't running.
-                             this method
+
-        :param str|unicode prefix: pick only those keys from ``gconfig`` that are prefixed with this string
+        :param dict gconfig: a "global" configuration dictionary whose values can be overridden by
-                                   (pass an empty string or ``None`` to use all keys)
+            keyword arguments to this method
+        :param str|unicode prefix: pick only those keys from ``gconfig`` that are prefixed with
+            this string (pass an empty string or ``None`` to use all keys)
         :raises SchedulerAlreadyRunningError: if the scheduler is already running
-        """
 
-        if self.running:
+        """
+        if self.state != STATE_STOPPED:
             raise SchedulerAlreadyRunningError
 
-        # If a non-empty prefix was given, strip it from the keys in the global configuration dict
+        # If a non-empty prefix was given, strip it from the keys in the
+        # global configuration dict
         if prefix:
             prefixlen = len(prefix)
-            gconfig = dict((key[prefixlen:], value) for key, value in six.iteritems(gconfig) if key.startswith(prefix))
+            gconfig = dict((key[prefixlen:], value) for key, value in six.iteritems(gconfig)
+                           if key.startswith(prefix))
 
-        # Create a structure from the dotted options (e.g. "a.b.c = d" -> {'a': {'b': {'c': 'd'}}})
+        # Create a structure from the dotted options
+        # (e.g. "a.b.c = d" -> {'a': {'b': {'c': 'd'}}})
         config = {}
         for key, value in six.iteritems(gconfig):
             parts = key.split('.')
@@ -94,15 +120,15 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         config.update(options)
         self._configure(config)
 
-    @abstractmethod
+    def start(self, paused=False):
-    def start(self):
         """
-        Starts the scheduler. The details of this process depend on the implementation.
+        Start the configured executors and job stores and begin processing scheduled jobs.
 
+        :param bool paused: if ``True``, don't start job processing until :meth:`resume` is called
         :raises SchedulerAlreadyRunningError: if the scheduler is already running
-        """
 
-        if self.running:
+        """
+        if self.state != STATE_STOPPED:
             raise SchedulerAlreadyRunningError
 
         with self._executors_lock:
@@ -125,29 +151,33 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
 
             # Schedule all pending jobs
             for job, jobstore_alias, replace_existing in self._pending_jobs:
-                self._real_add_job(job, jobstore_alias, replace_existing, False)
+                self._real_add_job(job, jobstore_alias, replace_existing)
             del self._pending_jobs[:]
 
-        self._stopped = False
+        self.state = STATE_PAUSED if paused else STATE_RUNNING
         self._logger.info('Scheduler started')
-
-        # Notify listeners that the scheduler has been started
         self._dispatch_event(SchedulerEvent(EVENT_SCHEDULER_START))
 
+        if not paused:
+            self.wakeup()
+
     @abstractmethod
     def shutdown(self, wait=True):
         """
-        Shuts down the scheduler. Does not interrupt any currently running jobs.
+        Shuts down the scheduler, along with its executors and job stores.
+
+        Does not interrupt any currently running jobs.
 
         :param bool wait: ``True`` to wait until all currently executing jobs have finished
         :raises SchedulerNotRunningError: if the scheduler has not been started yet
-        """
 
-        if not self.running:
+        """
+        if self.state == STATE_STOPPED:
             raise SchedulerNotRunningError
 
-        self._stopped = True
+        self.state = STATE_STOPPED
 
+        with self._jobstores_lock, self._executors_lock:
             # Shut down all executors
             for executor in six.itervalues(self._executors):
                 executor.shutdown(wait)
@@ -159,36 +189,71 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         self._logger.info('Scheduler has been shut down')
         self._dispatch_event(SchedulerEvent(EVENT_SCHEDULER_SHUTDOWN))
 
+    def pause(self):
+        """
+        Pause job processing in the scheduler.
+
+        This will prevent the scheduler from waking up to do job processing until :meth:`resume`
+        is called. It will not however stop any already running job processing.
+
+        """
+        if self.state == STATE_STOPPED:
+            raise SchedulerNotRunningError
+        elif self.state == STATE_RUNNING:
+            self.state = STATE_PAUSED
+            self._logger.info('Paused scheduler job processing')
+            self._dispatch_event(SchedulerEvent(EVENT_SCHEDULER_PAUSED))
+
+    def resume(self):
+        """Resume job processing in the scheduler."""
+        if self.state == STATE_STOPPED:
+            raise SchedulerNotRunningError
+        elif self.state == STATE_PAUSED:
+            self.state = STATE_RUNNING
+            self._logger.info('Resumed scheduler job processing')
+            self._dispatch_event(SchedulerEvent(EVENT_SCHEDULER_RESUMED))
+            self.wakeup()
+
     @property
     def running(self):
-        return not self._stopped
+        """
+        Return ``True`` if the scheduler has been started.
+
+        This is a shortcut for ``scheduler.state != STATE_STOPPED``.
+
+        """
+        return self.state != STATE_STOPPED
 
     def add_executor(self, executor, alias='default', **executor_opts):
         """
-        Adds an executor to this scheduler. Any extra keyword arguments will be passed to the executor plugin's
+        Adds an executor to this scheduler.
-        constructor, assuming that the first argument is the name of an executor plugin.
 
-        :param str|unicode|apscheduler.executors.base.BaseExecutor executor: either an executor instance or the name of
+        Any extra keyword arguments will be passed to the executor plugin's constructor, assuming
-            an executor plugin
+        that the first argument is the name of an executor plugin.
+
+        :param str|unicode|apscheduler.executors.base.BaseExecutor executor: either an executor
+            instance or the name of an executor plugin
         :param str|unicode alias: alias for the scheduler
         :raises ValueError: if there is already an executor by the given alias
-        """
 
+        """
         with self._executors_lock:
             if alias in self._executors:
-                raise ValueError('This scheduler already has an executor by the alias of "%s"' % alias)
+                raise ValueError('This scheduler already has an executor by the alias of "%s"' %
+                                 alias)
 
             if isinstance(executor, BaseExecutor):
                 self._executors[alias] = executor
             elif isinstance(executor, six.string_types):
-                self._executors[alias] = executor = self._create_plugin_instance('executor', executor, executor_opts)
+                self._executors[alias] = executor = self._create_plugin_instance(
+                    'executor', executor, executor_opts)
             else:
                 raise TypeError('Expected an executor instance or a string, got %s instead' %
                                 executor.__class__.__name__)
 
             # Start the executor right away if the scheduler is running
-            if self.running:
+            if self.state != STATE_STOPPED:
-                executor.start(self)
+                executor.start(self, alias)
 
         self._dispatch_event(SchedulerEvent(EVENT_EXECUTOR_ADDED, alias))
 
@@ -197,10 +262,11 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         Removes the executor by the given alias from this scheduler.
 
         :param str|unicode alias: alias of the executor
-        :param bool shutdown: ``True`` to shut down the executor after removing it
+        :param bool shutdown: ``True`` to shut down the executor after
-        """
+            removing it
 
-        with self._jobstores_lock:
+        """
+        with self._executors_lock:
             executor = self._lookup_executor(alias)
             del self._executors[alias]
 
@@ -211,35 +277,39 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
 
     def add_jobstore(self, jobstore, alias='default', **jobstore_opts):
         """
-        Adds a job store to this scheduler. Any extra keyword arguments will be passed to the job store plugin's
+        Adds a job store to this scheduler.
-        constructor, assuming that the first argument is the name of a job store plugin.
+
+        Any extra keyword arguments will be passed to the job store plugin's constructor, assuming
+        that the first argument is the name of a job store plugin.
 
         :param str|unicode|apscheduler.jobstores.base.BaseJobStore jobstore: job store to be added
         :param str|unicode alias: alias for the job store
         :raises ValueError: if there is already a job store by the given alias
-        """
 
+        """
         with self._jobstores_lock:
             if alias in self._jobstores:
-                raise ValueError('This scheduler already has a job store by the alias of "%s"' % alias)
+                raise ValueError('This scheduler already has a job store by the alias of "%s"' %
+                                 alias)
 
             if isinstance(jobstore, BaseJobStore):
                 self._jobstores[alias] = jobstore
             elif isinstance(jobstore, six.string_types):
-                self._jobstores[alias] = jobstore = self._create_plugin_instance('jobstore', jobstore, jobstore_opts)
+                self._jobstores[alias] = jobstore = self._create_plugin_instance(
+                    'jobstore', jobstore, jobstore_opts)
             else:
                 raise TypeError('Expected a job store instance or a string, got %s instead' %
                                 jobstore.__class__.__name__)
 
-            # Start the job store right away if the scheduler is running
+            # Start the job store right away if the scheduler isn't stopped
-            if self.running:
+            if self.state != STATE_STOPPED:
                 jobstore.start(self, alias)
 
         # Notify listeners that a new job store has been added
         self._dispatch_event(SchedulerEvent(EVENT_JOBSTORE_ADDED, alias))
 
         # Notify the scheduler so it can scan the new job store for jobs
-        if self.running:
+        if self.state != STATE_STOPPED:
             self.wakeup()
 
     def remove_jobstore(self, alias, shutdown=True):
@@ -248,8 +318,8 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
 
         :param str|unicode alias: alias of the job store
         :param bool shutdown: ``True`` to shut down the job store after removing it
-        """
 
+        """
         with self._jobstores_lock:
             jobstore = self._lookup_jobstore(alias)
             del self._jobstores[alias]
@@ -263,17 +333,20 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         """
         add_listener(callback, mask=EVENT_ALL)
 
-        Adds a listener for scheduler events. When a matching event occurs, ``callback`` is executed with the event
+        Adds a listener for scheduler events.
-        object as its sole argument. If the ``mask`` parameter is not provided, the callback will receive events of all
+
-        types.
+        When a matching event  occurs, ``callback`` is executed with the event object as its
+        sole argument. If the ``mask`` parameter is not provided, the callback will receive events
+        of all types.
 
         :param callback: any callable that takes one argument
-        :param int mask: bitmask that indicates which events should be listened to
+        :param int mask: bitmask that indicates which events should be
+            listened to
 
         .. seealso:: :mod:`apscheduler.events`
         .. seealso:: :ref:`scheduler-events`
-        """
 
+        """
         with self._listeners_lock:
             self._listeners.append((callback, mask))
 
@@ -285,47 +358,55 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
                 if callback == cb:
                     del self._listeners[i]
 
-    def add_job(self, func, trigger=None, args=None, kwargs=None, id=None, name=None, misfire_grace_time=undefined,
+    def add_job(self, func, trigger=None, args=None, kwargs=None, id=None, name=None,
-                coalesce=undefined, max_instances=undefined, next_run_time=undefined, jobstore='default',
+                misfire_grace_time=undefined, coalesce=undefined, max_instances=undefined,
-                executor='default', replace_existing=False, **trigger_args):
+                next_run_time=undefined, jobstore='default', executor='default',
+                replace_existing=False, **trigger_args):
         """
-        add_job(func, trigger=None, args=None, kwargs=None, id=None, name=None, misfire_grace_time=undefined, \
+        add_job(func, trigger=None, args=None, kwargs=None, id=None, \
-            coalesce=undefined, max_instances=undefined, next_run_time=undefined, jobstore='default', \
+            name=None, misfire_grace_time=undefined, coalesce=undefined, \
-            executor='default', replace_existing=False, **trigger_args)
+            max_instances=undefined, next_run_time=undefined, \
+            jobstore='default', executor='default', \
+            replace_existing=False, **trigger_args)
 
         Adds the given job to the job list and wakes up the scheduler if it's already running.
 
-        Any option that defaults to ``undefined`` will be replaced with the corresponding default value when the job is
+        Any option that defaults to ``undefined`` will be replaced with the corresponding default
-        scheduled (which happens when the scheduler is started, or immediately if the scheduler is already running).
+        value when the job is scheduled (which happens when the scheduler is started, or
+        immediately if the scheduler is already running).
 
-        The ``func`` argument can be given either as a callable object or a textual reference in the
+        The ``func`` argument can be given either as a callable object or a textual reference in
-        ``package.module:some.object`` format, where the first half (separated by ``:``) is an importable module and the
+        the ``package.module:some.object`` format, where the first half (separated by ``:``) is an
-        second half is a reference to the callable object, relative to the module.
+        importable module and the second half is a reference to the callable object, relative to
+        the module.
 
         The ``trigger`` argument can either be:
-          #. the alias name of the trigger (e.g. ``date``, ``interval`` or ``cron``), in which case any extra keyword
+          #. the alias name of the trigger (e.g. ``date``, ``interval`` or ``cron``), in which case
-             arguments to this method are passed on to the trigger's constructor
+            any extra keyword arguments to this method are passed on to the trigger's constructor
           #. an instance of a trigger class
 
         :param func: callable (or a textual reference to one) to run at the given time
-        :param str|apscheduler.triggers.base.BaseTrigger trigger: trigger that determines when ``func`` is called
+        :param str|apscheduler.triggers.base.BaseTrigger trigger: trigger that determines when
+            ``func`` is called
         :param list|tuple args: list of positional arguments to call func with
         :param dict kwargs: dict of keyword arguments to call func with
         :param str|unicode id: explicit identifier for the job (for modifying it later)
         :param str|unicode name: textual description of the job
-        :param int misfire_grace_time: seconds after the designated run time that the job is still allowed to be run
+        :param int misfire_grace_time: seconds after the designated runtime that the job is still
-        :param bool coalesce: run once instead of many times if the scheduler determines that the job should be run more
+            allowed to be run
-                              than once in succession
+        :param bool coalesce: run once instead of many times if the scheduler determines that the
-        :param int max_instances: maximum number of concurrently running instances allowed for this job
+            job should be run more than once in succession
-        :param datetime next_run_time: when to first run the job, regardless of the trigger (pass ``None`` to add the
+        :param int max_instances: maximum number of concurrently running instances allowed for this
-                                       job as paused)
+            job
+        :param datetime next_run_time: when to first run the job, regardless of the trigger (pass
+            ``None`` to add the job as paused)
         :param str|unicode jobstore: alias of the job store to store the job in
         :param str|unicode executor: alias of the executor to run the job with
-        :param bool replace_existing: ``True`` to replace an existing job with the same ``id`` (but retain the
+        :param bool replace_existing: ``True`` to replace an existing job with the same ``id``
-                                      number of runs from the existing one)
+            (but retain the number of runs from the existing one)
         :rtype: Job
-        """
 
+        """
         job_kwargs = {
             'trigger': self._create_trigger(trigger, trigger_args),
             'executor': executor,
@@ -339,45 +420,55 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
             'max_instances': max_instances,
             'next_run_time': next_run_time
         }
-        job_kwargs = dict((key, value) for key, value in six.iteritems(job_kwargs) if value is not undefined)
+        job_kwargs = dict((key, value) for key, value in six.iteritems(job_kwargs) if
+                          value is not undefined)
         job = Job(self, **job_kwargs)
 
         # Don't really add jobs to job stores before the scheduler is up and running
         with self._jobstores_lock:
-            if not self.running:
+            if self.state == STATE_STOPPED:
                 self._pending_jobs.append((job, jobstore, replace_existing))
-                self._logger.info('Adding job tentatively -- it will be properly scheduled when the scheduler starts')
+                self._logger.info('Adding job tentatively -- it will be properly scheduled when '
+                                  'the scheduler starts')
             else:
-                self._real_add_job(job, jobstore, replace_existing, True)
+                self._real_add_job(job, jobstore, replace_existing)
 
         return job
 
-    def scheduled_job(self, trigger, args=None, kwargs=None, id=None, name=None, misfire_grace_time=undefined,
+    def scheduled_job(self, trigger, args=None, kwargs=None, id=None, name=None,
-                      coalesce=undefined, max_instances=undefined, next_run_time=undefined, jobstore='default',
+                      misfire_grace_time=undefined, coalesce=undefined, max_instances=undefined,
-                      executor='default', **trigger_args):
+                      next_run_time=undefined, jobstore='default', executor='default',
+                      **trigger_args):
         """
-        scheduled_job(trigger, args=None, kwargs=None, id=None, name=None, misfire_grace_time=undefined, \
+        scheduled_job(trigger, args=None, kwargs=None, id=None, \
-            coalesce=undefined, max_instances=undefined, next_run_time=undefined, jobstore='default', \
+            name=None, misfire_grace_time=undefined, \
+            coalesce=undefined, max_instances=undefined, \
+            next_run_time=undefined, jobstore='default', \
             executor='default',**trigger_args)
 
-        A decorator version of :meth:`add_job`, except that ``replace_existing`` is always ``True``.
+        A decorator version of :meth:`add_job`, except that ``replace_existing`` is always
+        ``True``.
+
+        .. important:: The ``id`` argument must be given if scheduling a job in a persistent job
+        store. The scheduler cannot, however, enforce this requirement.
 
-        .. important:: The ``id`` argument must be given if scheduling a job in a persistent job store. The scheduler
-           cannot, however, enforce this requirement.
         """
-
         def inner(func):
-            self.add_job(func, trigger, args, kwargs, id, name, misfire_grace_time, coalesce, max_instances,
+            self.add_job(func, trigger, args, kwargs, id, name, misfire_grace_time, coalesce,
-                         next_run_time, jobstore, executor, True, **trigger_args)
+                         max_instances, next_run_time, jobstore, executor, True, **trigger_args)
             return func
         return inner
 
     def modify_job(self, job_id, jobstore=None, **changes):
         """
-        Modifies the properties of a single job. Modifications are passed to this method as extra keyword arguments.
+        Modifies the properties of a single job.
+
+        Modifications are passed to this method as extra keyword arguments.
 
         :param str|unicode job_id: the identifier of the job
         :param str|unicode jobstore: alias of the job store that contains the job
+        :return Job: the relevant job instance
+
         """
         with self._jobstores_lock:
             job, jobstore = self._lookup_job(job_id, jobstore)
@@ -388,22 +479,27 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         self._dispatch_event(JobEvent(EVENT_JOB_MODIFIED, job_id, jobstore))
 
         # Wake up the scheduler since the job's next run time may have been changed
+        if self.state == STATE_RUNNING:
             self.wakeup()
 
+        return job
+
     def reschedule_job(self, job_id, jobstore=None, trigger=None, **trigger_args):
         """
         Constructs a new trigger for a job and updates its next run time.
+
         Extra keyword arguments are passed directly to the trigger's constructor.
 
         :param str|unicode job_id: the identifier of the job
         :param str|unicode jobstore: alias of the job store that contains the job
         :param trigger: alias of the trigger type or a trigger instance
-        """
+        :return Job: the relevant job instance
 
+        """
         trigger = self._create_trigger(trigger, trigger_args)
         now = datetime.now(self.timezone)
         next_run_time = trigger.get_next_fire_time(None, now)
-        self.modify_job(job_id, jobstore, trigger=trigger, next_run_time=next_run_time)
+        return self.modify_job(job_id, jobstore, trigger=trigger, next_run_time=next_run_time)
 
     def pause_job(self, job_id, jobstore=None):
         """
@@ -411,9 +507,10 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
 
         :param str|unicode job_id: the identifier of the job
         :param str|unicode jobstore: alias of the job store that contains the job
-        """
+        :return Job: the relevant job instance
 
-        self.modify_job(job_id, jobstore, next_run_time=None)
+        """
+        return self.modify_job(job_id, jobstore, next_run_time=None)
 
     def resume_job(self, job_id, jobstore=None):
         """
@@ -421,38 +518,44 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
 
         :param str|unicode job_id: the identifier of the job
         :param str|unicode jobstore: alias of the job store that contains the job
-        """
+        :return Job|None: the relevant job instance if the job was rescheduled, or ``None`` if no
+            next run time could be calculated and the job was removed
 
+        """
         with self._jobstores_lock:
             job, jobstore = self._lookup_job(job_id, jobstore)
             now = datetime.now(self.timezone)
             next_run_time = job.trigger.get_next_fire_time(None, now)
             if next_run_time:
-                self.modify_job(job_id, jobstore, next_run_time=next_run_time)
+                return self.modify_job(job_id, jobstore, next_run_time=next_run_time)
             else:
                 self.remove_job(job.id, jobstore)
 
     def get_jobs(self, jobstore=None, pending=None):
         """
-        Returns a list of pending jobs (if the scheduler hasn't been started yet) and scheduled jobs, either from a
+        Returns a list of pending jobs (if the scheduler hasn't been started yet) and scheduled
-        specific job store or from all of them.
+        jobs, either from a specific job store or from all of them.
+
+        If the scheduler has not been started yet, only pending jobs can be returned because the
+        job stores haven't been started yet either.
 
         :param str|unicode jobstore: alias of the job store
-        :param bool pending: ``False`` to leave out pending jobs (jobs that are waiting for the scheduler start to be
+        :param bool pending: **DEPRECATED**
-                             added to their respective job stores), ``True`` to only include pending jobs, anything else
-                             to return both
         :rtype: list[Job]
+
         """
+        if pending is not None:
+            warnings.warn('The "pending" option is deprecated -- get_jobs() always returns '
+                          'pending jobs if the scheduler has been started and scheduled jobs '
+                          'otherwise', DeprecationWarning)
 
         with self._jobstores_lock:
             jobs = []
-
+            if self.state == STATE_STOPPED:
-            if pending is not False:
                 for job, alias, replace_existing in self._pending_jobs:
                     if jobstore is None or alias == jobstore:
                         jobs.append(job)
-
+            else:
-            if pending is not True:
                 for alias, store in six.iteritems(self._jobstores):
                     if jobstore is None or alias == jobstore:
                         jobs.extend(store.get_all_jobs())
@@ -467,8 +570,8 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         :param str|unicode jobstore: alias of the job store that most likely contains the job
         :return: the Job by the given ID, or ``None`` if it wasn't found
         :rtype: Job
-        """
 
+        """
         with self._jobstores_lock:
             try:
                 return self._lookup_job(job_id, jobstore)[0]
@@ -482,32 +585,35 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         :param str|unicode job_id: the identifier of the job
         :param str|unicode jobstore: alias of the job store that contains the job
         :raises JobLookupError: if the job was not found
-        """
 
+        """
+        jobstore_alias = None
         with self._jobstores_lock:
+            if self.state == STATE_STOPPED:
                 # Check if the job is among the pending jobs
-            for i, (job, jobstore_alias, replace_existing) in enumerate(self._pending_jobs):
+                if self.state == STATE_STOPPED:
-                if job.id == job_id:
+                    for i, (job, alias, replace_existing) in enumerate(self._pending_jobs):
+                        if job.id == job_id and jobstore in (None, alias):
                             del self._pending_jobs[i]
-                    jobstore = jobstore_alias
+                            jobstore_alias = alias
                             break
             else:
-                # Otherwise, try to remove it from each store until it succeeds or we run out of stores to check
+                # Otherwise, try to remove it from each store until it succeeds or we run out of
+                # stores to check
                 for alias, store in six.iteritems(self._jobstores):
                     if jobstore in (None, alias):
                         try:
                             store.remove_job(job_id)
+                            jobstore_alias = alias
+                            break
                         except JobLookupError:
                             continue
 
-                        jobstore = alias
+        if jobstore_alias is None:
-                        break
-
-        if jobstore is None:
             raise JobLookupError(job_id)
 
         # Notify listeners that a job has been removed
-        event = JobEvent(EVENT_JOB_REMOVED, job_id, jobstore)
+        event = JobEvent(EVENT_JOB_REMOVED, job_id, jobstore_alias)
         self._dispatch_event(event)
 
         self._logger.info('Removed job %s', job_id)
@@ -517,14 +623,16 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         Removes all jobs from the specified job store, or all job stores if none is given.
 
         :param str|unicode jobstore: alias of the job store
-        """
 
+        """
         with self._jobstores_lock:
+            if self.state == STATE_STOPPED:
                 if jobstore:
-                self._pending_jobs = [pending for pending in self._pending_jobs if pending[1] != jobstore]
+                    self._pending_jobs = [pending for pending in self._pending_jobs if
+                                          pending[1] != jobstore]
                 else:
                     self._pending_jobs = []
-
+            else:
                 for alias, store in six.iteritems(self._jobstores):
                     if jobstore in (None, alias):
                         store.remove_all_jobs()
@@ -535,29 +643,34 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         """
         print_jobs(jobstore=None, out=sys.stdout)
 
-        Prints out a textual listing of all jobs currently scheduled on either all job stores or just a specific one.
+        Prints out a textual listing of all jobs currently scheduled on either all job stores or
+        just a specific one.
 
         :param str|unicode jobstore: alias of the job store, ``None`` to list jobs from all stores
-        :param file out: a file-like object to print to (defaults to **sys.stdout** if nothing is given)
+        :param file out: a file-like object to print to (defaults to  **sys.stdout** if nothing is
-        """
+            given)
 
+        """
         out = out or sys.stdout
         with self._jobstores_lock:
+            if self.state == STATE_STOPPED:
+                print(u'Pending jobs:', file=out)
                 if self._pending_jobs:
-                print(six.u('Pending jobs:'), file=out)
                     for job, jobstore_alias, replace_existing in self._pending_jobs:
                         if jobstore in (None, jobstore_alias):
-                        print(six.u('    %s') % job, file=out)
+                            print(u'    %s' % job, file=out)
-
+                else:
-            for alias, store in six.iteritems(self._jobstores):
+                    print(u'    No pending jobs', file=out)
+            else:
+                for alias, store in sorted(six.iteritems(self._jobstores)):
                     if jobstore in (None, alias):
-                    print(six.u('Jobstore %s:') % alias, file=out)
+                        print(u'Jobstore %s:' % alias, file=out)
                         jobs = store.get_all_jobs()
                         if jobs:
                             for job in jobs:
-                            print(six.u('    %s') % job, file=out)
+                                print(u'    %s' % job, file=out)
                         else:
-                        print(six.u('    No scheduled jobs'), file=out)
+                            print(u'    No scheduled jobs', file=out)
 
     @abstractmethod
     def wakeup(self):
@@ -574,6 +687,7 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         # Set general options
         self._logger = maybe_ref(config.pop('logger', None)) or getLogger('apscheduler.scheduler')
         self.timezone = astimezone(config.pop('timezone', None)) or get_localzone()
+        self.jobstore_retry_interval = float(config.pop('jobstore_retry_interval', 10))
 
         # Set the job defaults
         job_defaults = config.get('job_defaults', {})
@@ -597,12 +711,15 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
                     cls = maybe_ref(executor_class)
                     executor = cls(**value)
                 else:
-                    raise ValueError('Cannot create executor "%s" -- either "type" or "class" must be defined' % alias)
+                    raise ValueError(
+                        'Cannot create executor "%s" -- either "type" or "class" must be defined' %
+                        alias)
 
                 self.add_executor(executor, alias)
             else:
-                raise TypeError("Expected executor instance or dict for executors['%s'], got %s instead" % (
+                raise TypeError(
-                    alias, value.__class__.__name__))
+                    "Expected executor instance or dict for executors['%s'], got %s instead" %
+                    (alias, value.__class__.__name__))
 
         # Configure job stores
         self._jobstores.clear()
@@ -618,31 +735,33 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
                     cls = maybe_ref(jobstore_class)
                     jobstore = cls(**value)
                 else:
-                    raise ValueError('Cannot create job store "%s" -- either "type" or "class" must be defined' % alias)
+                    raise ValueError(
+                        'Cannot create job store "%s" -- either "type" or "class" must be '
+                        'defined' % alias)
 
                 self.add_jobstore(jobstore, alias)
             else:
-                raise TypeError("Expected job store instance or dict for jobstores['%s'], got %s instead" % (
+                raise TypeError(
-                    alias, value.__class__.__name__))
+                    "Expected job store instance or dict for jobstores['%s'], got %s instead" %
+                    (alias, value.__class__.__name__))
 
     def _create_default_executor(self):
         """Creates a default executor store, specific to the particular scheduler type."""
-
         return ThreadPoolExecutor()
 
     def _create_default_jobstore(self):
         """Creates a default job store, specific to the particular scheduler type."""
-
         return MemoryJobStore()
 
     def _lookup_executor(self, alias):
         """
-        Returns the executor instance by the given name from the list of executors that were added to this scheduler.
+        Returns the executor instance by the given name from the list of executors that were added
+        to this scheduler.
 
         :type alias: str
         :raises KeyError: if no executor by the given alias is not found
-        """
 
+        """
         try:
             return self._executors[alias]
         except KeyError:
@@ -650,12 +769,13 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
 
     def _lookup_jobstore(self, alias):
         """
-        Returns the job store instance by the given name from the list of job stores that were added to this scheduler.
+        Returns the job store instance by the given name from the list of job stores that were
+        added to this scheduler.
 
         :type alias: str
         :raises KeyError: if no job store by the given alias is not found
-        """
 
+        """
         try:
             return self._jobstores[alias]
         except KeyError:
@@ -667,15 +787,17 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
 
         :type job_id: str
         :param str jobstore_alias: alias of a job store to look in
-        :return tuple[Job, str]: a tuple of job, jobstore alias (jobstore alias is None in case of a pending job)
+        :return tuple[Job, str]: a tuple of job, jobstore alias (jobstore alias is None in case of
+            a pending job)
         :raises JobLookupError: if no job by the given ID is found.
-        """
 
+        """
+        if self.state == STATE_STOPPED:
             # Check if the job is among the pending jobs
             for job, alias, replace_existing in self._pending_jobs:
                 if job.id == job_id:
                     return job, None
-
+        else:
             # Look in all job stores
             for alias, store in six.iteritems(self._jobstores):
                 if jobstore_alias in (None, alias):
@@ -690,8 +812,8 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         Dispatches the given event to interested listeners.
 
         :param SchedulerEvent event: the event to send
-        """
 
+        """
         with self._listeners_lock:
             listeners = tuple(self._listeners)
 
@@ -699,16 +821,16 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
             if event.code & mask:
                 try:
                     cb(event)
-                except:
+                except BaseException:
                     self._logger.exception('Error notifying listener')
 
-    def _real_add_job(self, job, jobstore_alias, replace_existing, wakeup):
+    def _real_add_job(self, job, jobstore_alias, replace_existing):
         """
         :param Job job: the job to add
-        :param bool replace_existing: ``True`` to use update_job() in case the job already exists in the store
+        :param bool replace_existing: ``True`` to use update_job() in case the job already exists
-        :param bool wakeup: ``True`` to wake up the scheduler after adding the job
+            in the store
-        """
 
+        """
         # Fill in undefined values with defaults
         replacements = {}
         for key, value in six.iteritems(self._job_defaults):
@@ -743,12 +865,11 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         self._logger.info('Added job "%s" to job store "%s"', job.name, jobstore_alias)
 
         # Notify the scheduler about the new job
-        if wakeup:
+        if self.state == STATE_RUNNING:
             self.wakeup()
 
     def _create_plugin_instance(self, type_, alias, constructor_kwargs):
         """Creates an instance of the given plugin type, loading the plugin first if necessary."""
-
         plugin_container, class_container, base_class = {
             'trigger': (self._trigger_plugins, self._trigger_classes, BaseTrigger),
             'jobstore': (self._jobstore_plugins, self._jobstore_classes, BaseJobStore),
@@ -761,7 +882,8 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
             if alias in plugin_container:
                 plugin_cls = class_container[alias] = plugin_container[alias].load()
                 if not issubclass(plugin_cls, base_class):
-                    raise TypeError('The {0} entry point does not point to a {0} class'.format(type_))
+                    raise TypeError('The {0} entry point does not point to a {0} class'.
+                                    format(type_))
             else:
                 raise LookupError('No {0} by the name "{1}" was found'.format(type_, alias))
 
@@ -773,7 +895,8 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
         elif trigger is None:
             trigger = 'date'
         elif not isinstance(trigger, six.string_types):
-            raise TypeError('Expected a trigger instance or string, got %s instead' % trigger.__class__.__name__)
+            raise TypeError('Expected a trigger instance or string, got %s instead' %
+                            trigger.__class__.__name__)
 
         # Use the scheduler's time zone if nothing else is specified
         trigger_args.setdefault('timezone', self.timezone)
@@ -783,29 +906,48 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
 
     def _create_lock(self):
         """Creates a reentrant lock object."""
-
         return RLock()
 
     def _process_jobs(self):
         """
-        Iterates through jobs in every jobstore, starts jobs that are due and figures out how long to wait for the next
+        Iterates through jobs in every jobstore, starts jobs that are due and figures out how long
-        round.
+        to wait for the next round.
+
+        If the ``get_due_jobs()`` call raises an exception, a new wakeup is scheduled in at least
+        ``jobstore_retry_interval`` seconds.
+
         """
+        if self.state == STATE_PAUSED:
+            self._logger.debug('Scheduler is paused -- not processing jobs')
+            return None
 
         self._logger.debug('Looking for jobs to run')
         now = datetime.now(self.timezone)
         next_wakeup_time = None
+        events = []
 
         with self._jobstores_lock:
             for jobstore_alias, jobstore in six.iteritems(self._jobstores):
-                for job in jobstore.get_due_jobs(now):
+                try:
+                    due_jobs = jobstore.get_due_jobs(now)
+                except Exception as e:
+                    # Schedule a wakeup at least in jobstore_retry_interval seconds
+                    self._logger.warning('Error getting due jobs from job store %r: %s',
+                                         jobstore_alias, e)
+                    retry_wakeup_time = now + timedelta(seconds=self.jobstore_retry_interval)
+                    if not next_wakeup_time or next_wakeup_time > retry_wakeup_time:
+                        next_wakeup_time = retry_wakeup_time
+
+                    continue
+
+                for job in due_jobs:
                     # Look up the job's executor
                     try:
                         executor = self._lookup_executor(job.executor)
-                    except:
+                    except BaseException:
                         self._logger.error(
-                            'Executor lookup ("%s") failed for job "%s" -- removing it from the job store',
+                            'Executor lookup ("%s") failed for job "%s" -- removing it from the '
-                            job.executor, job)
+                            'job store', job.executor, job)
                         self.remove_job(job.id, jobstore_alias)
                         continue
 
@@ -816,12 +958,21 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
                             executor.submit_job(job, run_times)
                         except MaxInstancesReachedError:
                             self._logger.warning(
-                                'Execution of job "%s" skipped: maximum number of running instances reached (%d)',
+                                'Execution of job "%s" skipped: maximum number of running '
-                                job, job.max_instances)
+                                'instances reached (%d)', job, job.max_instances)
-                        except:
+                            event = JobSubmissionEvent(EVENT_JOB_MAX_INSTANCES, job.id,
-                            self._logger.exception('Error submitting job "%s" to executor "%s"', job, job.executor)
+                                                       jobstore_alias, run_times)
+                            events.append(event)
+                        except BaseException:
+                            self._logger.exception('Error submitting job "%s" to executor "%s"',
+                                                   job, job.executor)
+                        else:
+                            event = JobSubmissionEvent(EVENT_JOB_SUBMITTED, job.id, jobstore_alias,
+                                                       run_times)
+                            events.append(event)
 
-                        # Update the job if it has a next execution time. Otherwise remove it from the job store.
+                        # Update the job if it has a next execution time.
+                        # Otherwise remove it from the job store.
                         job_next_run = job.trigger.get_next_fire_time(run_times[-1], now)
                         if job_next_run:
                             job._modify(next_run_time=job_next_run)
@@ -829,17 +980,27 @@ class BaseScheduler(six.with_metaclass(ABCMeta)):
                         else:
                             self.remove_job(job.id, jobstore_alias)
 
-                # Set a new next wakeup time if there isn't one yet or the jobstore has an even earlier one
+                # Set a new next wakeup time if there isn't one yet or
+                # the jobstore has an even earlier one
                 jobstore_next_run_time = jobstore.get_next_run_time()
-                if jobstore_next_run_time and (next_wakeup_time is None or jobstore_next_run_time < next_wakeup_time):
+                if jobstore_next_run_time and (next_wakeup_time is None or
-                    next_wakeup_time = jobstore_next_run_time
+                                               jobstore_next_run_time < next_wakeup_time):
+                    next_wakeup_time = jobstore_next_run_time.astimezone(self.timezone)
+
+        # Dispatch collected events
+        for event in events:
+            self._dispatch_event(event)
 
         # Determine the delay until this method should be called again
-        if next_wakeup_time is not None:
+        if self.state == STATE_PAUSED:
-            wait_seconds = max(timedelta_seconds(next_wakeup_time - now), 0)
+            wait_seconds = None
-            self._logger.debug('Next wakeup is due at %s (in %f seconds)', next_wakeup_time, wait_seconds)
+            self._logger.debug('Scheduler is paused; waiting until resume() is called')
-        else:
+        elif next_wakeup_time is None:
             wait_seconds = None
             self._logger.debug('No jobs; waiting until a job is added')
+        else:
+            wait_seconds = max(timedelta_seconds(next_wakeup_time - now), 0)
+            self._logger.debug('Next wakeup is due at %s (in %f seconds)', next_wakeup_time,
+                               wait_seconds)
 
         return wait_seconds

lib/apscheduler/schedulers/blocking.py

@@ -1,21 +1,21 @@
 from __future__ import absolute_import
+
 from threading import Event
 
-from apscheduler.schedulers.base import BaseScheduler
+from apscheduler.schedulers.base import BaseScheduler, STATE_STOPPED
+from apscheduler.util import TIMEOUT_MAX
 
 
 class BlockingScheduler(BaseScheduler):
     """
-    A scheduler that runs in the foreground (:meth:`~apscheduler.schedulers.base.BaseScheduler.start` will block).
+    A scheduler that runs in the foreground
+    (:meth:`~apscheduler.schedulers.base.BaseScheduler.start` will block).
     """
-
-    MAX_WAIT_TIME = 4294967  # Maximum value accepted by Event.wait() on Windows
-
     _event = None
 
-    def start(self):
+    def start(self, *args, **kwargs):
-        super(BlockingScheduler, self).start()
         self._event = Event()
+        super(BlockingScheduler, self).start(*args, **kwargs)
         self._main_loop()
 
     def shutdown(self, wait=True):
@@ -23,10 +23,11 @@ class BlockingScheduler(BaseScheduler):
         self._event.set()
 
     def _main_loop(self):
-        while self.running:
+        wait_seconds = TIMEOUT_MAX
-            wait_seconds = self._process_jobs()
+        while self.state != STATE_STOPPED:
-            self._event.wait(wait_seconds if wait_seconds is not None else self.MAX_WAIT_TIME)
+            self._event.wait(wait_seconds)
             self._event.clear()
+            wait_seconds = self._process_jobs()
 
     def wakeup(self):
         self._event.set()

lib/apscheduler/schedulers/gevent.py

@@ -16,14 +16,14 @@ class GeventScheduler(BlockingScheduler):
 
     _greenlet = None
 
-    def start(self):
+    def start(self, *args, **kwargs):
-        BaseScheduler.start(self)
         self._event = Event()
+        BaseScheduler.start(self, *args, **kwargs)
         self._greenlet = gevent.spawn(self._main_loop)
         return self._greenlet
 
-    def shutdown(self, wait=True):
+    def shutdown(self, *args, **kwargs):
-        super(GeventScheduler, self).shutdown(wait)
+        super(GeventScheduler, self).shutdown(*args, **kwargs)
         self._greenlet.join()
         del self._greenlet
 

lib/apscheduler/schedulers/qt.py

@@ -4,7 +4,7 @@ from apscheduler.schedulers.base import BaseScheduler
 
 try:
     from PyQt5.QtCore import QObject, QTimer
-except ImportError:  # pragma: nocover
+except (ImportError, RuntimeError):  # pragma: nocover
     try:
         from PyQt4.QtCore import QObject, QTimer
     except ImportError:
@@ -19,12 +19,8 @@ class QtScheduler(BaseScheduler):
 
     _timer = None
 
-    def start(self):
+    def shutdown(self, *args, **kwargs):
-        super(QtScheduler, self).start()
+        super(QtScheduler, self).shutdown(*args, **kwargs)
-        self.wakeup()
-
-    def shutdown(self, wait=True):
-        super(QtScheduler, self).shutdown(wait)
         self._stop_timer()
 
     def _start_timer(self, wait_seconds):

lib/apscheduler/schedulers/tornado.py

@@ -1,4 +1,5 @@
 from __future__ import absolute_import
+
 from datetime import timedelta
 from functools import wraps
 
@@ -22,6 +23,8 @@ class TornadoScheduler(BaseScheduler):
     """
     A scheduler that runs on a Tornado IOLoop.
 
+    The default executor can run jobs based on native coroutines (``async def``).
+
     =========== ===============================================================
     ``io_loop`` Tornado IOLoop instance to use (defaults to the global IO loop)
     =========== ===============================================================
@@ -30,10 +33,6 @@ class TornadoScheduler(BaseScheduler):
     _ioloop = None
     _timeout = None
 
-    def start(self):
-        super(TornadoScheduler, self).start()
-        self.wakeup()
-
     @run_in_ioloop
     def shutdown(self, wait=True):
         super(TornadoScheduler, self).shutdown(wait)
@@ -53,6 +52,10 @@ class TornadoScheduler(BaseScheduler):
             self._ioloop.remove_timeout(self._timeout)
             del self._timeout
 
+    def _create_default_executor(self):
+        from apscheduler.executors.tornado import TornadoExecutor
+        return TornadoExecutor()
+
     @run_in_ioloop
     def wakeup(self):
         self._stop_timer()

lib/apscheduler/schedulers/twisted.py

@@ -1,4 +1,5 @@
 from __future__ import absolute_import
+
 from functools import wraps
 
 from apscheduler.schedulers.base import BaseScheduler
@@ -35,10 +36,6 @@ class TwistedScheduler(BaseScheduler):
         self._reactor = maybe_ref(config.pop('reactor', default_reactor))
         super(TwistedScheduler, self)._configure(config)
 
-    def start(self):
-        super(TwistedScheduler, self).start()
-        self.wakeup()
-
     @run_in_reactor
     def shutdown(self, wait=True):
         super(TwistedScheduler, self).shutdown(wait)

lib/apscheduler/triggers/base.py

@@ -1,4 +1,6 @@
 from abc import ABCMeta, abstractmethod
+from datetime import timedelta
+import random
 
 import six
 
@@ -6,11 +8,41 @@ import six
 class BaseTrigger(six.with_metaclass(ABCMeta)):
     """Abstract base class that defines the interface that every trigger must implement."""
 
+    __slots__ = ()
+
     @abstractmethod
     def get_next_fire_time(self, previous_fire_time, now):
         """
-        Returns the next datetime to fire on, If no such datetime can be calculated, returns ``None``.
+        Returns the next datetime to fire on, If no such datetime can be calculated, returns
+        ``None``.
 
         :param datetime.datetime previous_fire_time: the previous time the trigger was fired
         :param datetime.datetime now: current datetime
         """
+
+    def _apply_jitter(self, next_fire_time, jitter, now):
+        """
+        Randomize ``next_fire_time`` by adding or subtracting a random value (the jitter). If the
+        resulting datetime is in the past, returns the initial ``next_fire_time`` without jitter.
+
+        ``next_fire_time - jitter <= result <= next_fire_time + jitter``
+
+        :param datetime.datetime|None next_fire_time: next fire time without jitter applied. If
+            ``None``, returns ``None``.
+        :param int|None jitter: maximum number of seconds to add or subtract to
+            ``next_fire_time``. If ``None`` or ``0``, returns ``next_fire_time``
+        :param datetime.datetime now: current datetime
+        :return datetime.datetime|None: next fire time with a jitter.
+        """
+        if next_fire_time is None or not jitter:
+            return next_fire_time
+
+        next_fire_time_with_jitter = next_fire_time + timedelta(
+                seconds=random.uniform(-jitter, jitter))
+
+        if next_fire_time_with_jitter < now:
+            # Next fire time with jitter is in the past.
+            # Ignore jitter to avoid false misfire.
+            return next_fire_time
+
+        return next_fire_time_with_jitter

lib/apscheduler/triggers/combining.py

@@ -0,0 +1,95 @@
+from apscheduler.triggers.base import BaseTrigger
+from apscheduler.util import obj_to_ref, ref_to_obj
+
+
+class BaseCombiningTrigger(BaseTrigger):
+    __slots__ = ('triggers', 'jitter')
+
+    def __init__(self, triggers, jitter=None):
+        self.triggers = triggers
+        self.jitter = jitter
+
+    def __getstate__(self):
+        return {
+            'version': 1,
+            'triggers': [(obj_to_ref(trigger.__class__), trigger.__getstate__())
+                         for trigger in self.triggers],
+            'jitter': self.jitter
+        }
+
+    def __setstate__(self, state):
+        if state.get('version', 1) > 1:
+            raise ValueError(
+                'Got serialized data for version %s of %s, but only versions up to 1 can be '
+                'handled' % (state['version'], self.__class__.__name__))
+
+        self.jitter = state['jitter']
+        self.triggers = []
+        for clsref, state in state['triggers']:
+            cls = ref_to_obj(clsref)
+            trigger = cls.__new__(cls)
+            trigger.__setstate__(state)
+            self.triggers.append(trigger)
+
+    def __repr__(self):
+        return '<{}({}{})>'.format(self.__class__.__name__, self.triggers,
+                                   ', jitter={}'.format(self.jitter) if self.jitter else '')
+
+
+class AndTrigger(BaseCombiningTrigger):
+    """
+    Always returns the earliest next fire time that all the given triggers can agree on.
+    The trigger is considered to be finished when any of the given triggers has finished its
+    schedule.
+
+    Trigger alias: ``and``
+
+    :param list triggers: triggers to combine
+    :param int|None jitter: advance or delay the job execution by ``jitter`` seconds at most.
+    """
+
+    __slots__ = ()
+
+    def get_next_fire_time(self, previous_fire_time, now):
+        while True:
+            fire_times = [trigger.get_next_fire_time(previous_fire_time, now)
+                          for trigger in self.triggers]
+            if None in fire_times:
+                return None
+            elif min(fire_times) == max(fire_times):
+                return self._apply_jitter(fire_times[0], self.jitter, now)
+            else:
+                now = max(fire_times)
+
+    def __str__(self):
+        return 'and[{}]'.format(', '.join(str(trigger) for trigger in self.triggers))
+
+
+class OrTrigger(BaseCombiningTrigger):
+    """
+    Always returns the earliest next fire time produced by any of the given triggers.
+    The trigger is considered finished when all the given triggers have finished their schedules.
+
+    Trigger alias: ``or``
+
+    :param list triggers: triggers to combine
+    :param int|None jitter: advance or delay the job execution by ``jitter`` seconds at most.
+
+    .. note:: Triggers that depends on the previous fire time, such as the interval trigger, may
+        seem to behave strangely since they are always passed the previous fire time produced by
+        any of the given triggers.
+    """
+
+    __slots__ = ()
+
+    def get_next_fire_time(self, previous_fire_time, now):
+        fire_times = [trigger.get_next_fire_time(previous_fire_time, now)
+                      for trigger in self.triggers]
+        fire_times = [fire_time for fire_time in fire_times if fire_time is not None]
+        if fire_times:
+            return self._apply_jitter(min(fire_times), self.jitter, now)
+        else:
+            return None
+
+    def __str__(self):
+        return 'or[{}]'.format(', '.join(str(trigger) for trigger in self.triggers))

lib/apscheduler/triggers/cron/__init__.py

@@ -4,13 +4,15 @@ from tzlocal import get_localzone
 import six
 
 from apscheduler.triggers.base import BaseTrigger
-from apscheduler.triggers.cron.fields import BaseField, WeekField, DayOfMonthField, DayOfWeekField, DEFAULT_VALUES
+from apscheduler.triggers.cron.fields import (
+    BaseField, MonthField, WeekField, DayOfMonthField, DayOfWeekField, DEFAULT_VALUES)
 from apscheduler.util import datetime_ceil, convert_to_datetime, datetime_repr, astimezone
 
 
 class CronTrigger(BaseTrigger):
     """
-    Triggers when current time matches all specified time constraints, similarly to how the UNIX cron scheduler works.
+    Triggers when current time matches all specified time constraints,
+    similarly to how the UNIX cron scheduler works.
 
     :param int|str year: 4-digit year
     :param int|str month: month (1-12)
@@ -22,8 +24,9 @@ class CronTrigger(BaseTrigger):
     :param int|str second: second (0-59)
     :param datetime|str start_date: earliest possible date/time to trigger on (inclusive)
     :param datetime|str end_date: latest possible date/time to trigger on (inclusive)
-    :param datetime.tzinfo|str timezone: time zone to use for the date/time calculations
+    :param datetime.tzinfo|str timezone: time zone to use for the date/time calculations (defaults
-                                         (defaults to scheduler timezone)
+        to scheduler timezone)
+    :param int|None jitter: advance or delay the job execution by ``jitter`` seconds at most.
 
     .. note:: The first weekday is always **monday**.
     """
@@ -31,7 +34,7 @@ class CronTrigger(BaseTrigger):
     FIELD_NAMES = ('year', 'month', 'day', 'week', 'day_of_week', 'hour', 'minute', 'second')
     FIELDS_MAP = {
         'year': BaseField,
-        'month': BaseField,
+        'month': MonthField,
         'week': WeekField,
         'day': DayOfMonthField,
         'day_of_week': DayOfWeekField,
@@ -40,15 +43,16 @@ class CronTrigger(BaseTrigger):
         'second': BaseField
     }
 
-    __slots__ = 'timezone', 'start_date', 'end_date', 'fields'
+    __slots__ = 'timezone', 'start_date', 'end_date', 'fields', 'jitter'
 
-    def __init__(self, year=None, month=None, day=None, week=None, day_of_week=None, hour=None, minute=None,
+    def __init__(self, year=None, month=None, day=None, week=None, day_of_week=None, hour=None,
-                 second=None, start_date=None, end_date=None, timezone=None):
+                 minute=None, second=None, start_date=None, end_date=None, timezone=None,
+                 jitter=None):
         if timezone:
             self.timezone = astimezone(timezone)
-        elif start_date and start_date.tzinfo:
+        elif isinstance(start_date, datetime) and start_date.tzinfo:
             self.timezone = start_date.tzinfo
-        elif end_date and end_date.tzinfo:
+        elif isinstance(end_date, datetime) and end_date.tzinfo:
             self.timezone = end_date.tzinfo
         else:
             self.timezone = get_localzone()
@@ -56,6 +60,8 @@ class CronTrigger(BaseTrigger):
         self.start_date = convert_to_datetime(start_date, self.timezone, 'start_date')
         self.end_date = convert_to_datetime(end_date, self.timezone, 'end_date')
 
+        self.jitter = jitter
+
         values = dict((key, value) for (key, value) in six.iteritems(locals())
                       if key in self.FIELD_NAMES and value is not None)
         self.fields = []
@@ -76,13 +82,35 @@ class CronTrigger(BaseTrigger):
             field = field_class(field_name, exprs, is_default)
             self.fields.append(field)
 
+    @classmethod
+    def from_crontab(cls, expr, timezone=None):
+        """
+        Create a :class:`~CronTrigger` from a standard crontab expression.
+
+        See https://en.wikipedia.org/wiki/Cron for more information on the format accepted here.
+
+        :param expr: minute, hour, day of month, month, day of week
+        :param datetime.tzinfo|str timezone: time zone to use for the date/time calculations (
+            defaults to scheduler timezone)
+        :return: a :class:`~CronTrigger` instance
+
+        """
+        values = expr.split()
+        if len(values) != 5:
+            raise ValueError('Wrong number of fields; got {}, expected 5'.format(len(values)))
+
+        return cls(minute=values[0], hour=values[1], day=values[2], month=values[3],
+                   day_of_week=values[4], timezone=timezone)
+
     def _increment_field_value(self, dateval, fieldnum):
         """
-        Increments the designated field and resets all less significant fields to their minimum values.
+        Increments the designated field and resets all less significant fields to their minimum
+        values.
 
         :type dateval: datetime
         :type fieldnum: int
-        :return: a tuple containing the new date, and the number of the field that was actually incremented
+        :return: a tuple containing the new date, and the number of the field that was actually
+            incremented
         :rtype: tuple
         """
 
@@ -128,12 +156,13 @@ class CronTrigger(BaseTrigger):
                 else:
                     values[field.name] = new_value
 
-        difference = datetime(**values) - dateval.replace(tzinfo=None)
+        return self.timezone.localize(datetime(**values))
-        return self.timezone.normalize(dateval + difference)
 
     def get_next_fire_time(self, previous_fire_time, now):
         if previous_fire_time:
-            start_date = max(now, previous_fire_time + timedelta(microseconds=1))
+            start_date = min(now, previous_fire_time + timedelta(microseconds=1))
+            if start_date == previous_fire_time:
+                start_date += timedelta(microseconds=1)
         else:
             start_date = max(now, self.start_date) if self.start_date else now
 
@@ -163,8 +192,36 @@ class CronTrigger(BaseTrigger):
                 return None
 
         if fieldnum >= 0:
+            if self.jitter is not None:
+                next_date = self._apply_jitter(next_date, self.jitter, now)
             return next_date
 
+    def __getstate__(self):
+        return {
+            'version': 2,
+            'timezone': self.timezone,
+            'start_date': self.start_date,
+            'end_date': self.end_date,
+            'fields': self.fields,
+            'jitter': self.jitter,
+        }
+
+    def __setstate__(self, state):
+        # This is for compatibility with APScheduler 3.0.x
+        if isinstance(state, tuple):
+            state = state[1]
+
+        if state.get('version', 1) > 2:
+            raise ValueError(
+                'Got serialized data for version %s of %s, but only versions up to 2 can be '
+                'handled' % (state['version'], self.__class__.__name__))
+
+        self.timezone = state['timezone']
+        self.start_date = state['start_date']
+        self.end_date = state['end_date']
+        self.fields = state['fields']
+        self.jitter = state.get('jitter')
+
     def __str__(self):
         options = ["%s='%s'" % (f.name, f) for f in self.fields if not f.is_default]
         return 'cron[%s]' % (', '.join(options))
@@ -172,5 +229,11 @@ class CronTrigger(BaseTrigger):
     def __repr__(self):
         options = ["%s='%s'" % (f.name, f) for f in self.fields if not f.is_default]
         if self.start_date:
-            options.append("start_date='%s'" % datetime_repr(self.start_date))
+            options.append("start_date=%r" % datetime_repr(self.start_date))
-        return '<%s (%s)>' % (self.__class__.__name__, ', '.join(options))
+        if self.end_date:
+            options.append("end_date=%r" % datetime_repr(self.end_date))
+        if self.jitter:
+            options.append('jitter=%s' % self.jitter)
+
+        return "<%s (%s, timezone='%s')>" % (
+            self.__class__.__name__, ', '.join(options), self.timezone)

lib/apscheduler/triggers/cron/expressions.py

@@ -1,17 +1,16 @@
-"""
+"""This module contains the expressions applicable for CronTrigger's fields."""
-This module contains the expressions applicable for CronTrigger's fields.
-"""
 
 from calendar import monthrange
 import re
 
 from apscheduler.util import asint
 
-__all__ = ('AllExpression', 'RangeExpression', 'WeekdayRangeExpression', 'WeekdayPositionExpression',
+__all__ = ('AllExpression', 'RangeExpression', 'WeekdayRangeExpression',
-           'LastDayOfMonthExpression')
+           'WeekdayPositionExpression', 'LastDayOfMonthExpression')
 
 
 WEEKDAYS = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun']
+MONTHS = ['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug', 'sep', 'oct', 'nov', 'dec']
 
 
 class AllExpression(object):
@@ -22,6 +21,14 @@ class AllExpression(object):
         if self.step == 0:
             raise ValueError('Increment must be higher than 0')
 
+    def validate_range(self, field_name):
+        from apscheduler.triggers.cron.fields import MIN_VALUES, MAX_VALUES
+
+        value_range = MAX_VALUES[field_name] - MIN_VALUES[field_name]
+        if self.step and self.step > value_range:
+            raise ValueError('the step value ({}) is higher than the total range of the '
+                             'expression ({})'.format(self.step, value_range))
+
     def get_next_value(self, date, field):
         start = field.get_value(date)
         minval = field.get_min(date)
@@ -37,6 +44,9 @@ class AllExpression(object):
         if next <= maxval:
             return next
 
+    def __eq__(self, other):
+        return isinstance(other, self.__class__) and self.step == other.step
+
     def __str__(self):
         if self.step:
             return '*/%d' % self.step
@@ -51,7 +61,7 @@ class RangeExpression(AllExpression):
         r'(?P<first>\d+)(?:-(?P<last>\d+))?(?:/(?P<step>\d+))?$')
 
     def __init__(self, first, last=None, step=None):
-        AllExpression.__init__(self, step)
+        super(RangeExpression, self).__init__(step)
         first = asint(first)
         last = asint(last)
         if last is None and step is None:
@@ -61,25 +71,41 @@ class RangeExpression(AllExpression):
         self.first = first
         self.last = last
 
+    def validate_range(self, field_name):
+        from apscheduler.triggers.cron.fields import MIN_VALUES, MAX_VALUES
+
+        super(RangeExpression, self).validate_range(field_name)
+        if self.first < MIN_VALUES[field_name]:
+            raise ValueError('the first value ({}) is lower than the minimum value ({})'
+                             .format(self.first, MIN_VALUES[field_name]))
+        if self.last is not None and self.last > MAX_VALUES[field_name]:
+            raise ValueError('the last value ({}) is higher than the maximum value ({})'
+                             .format(self.last, MAX_VALUES[field_name]))
+        value_range = (self.last or MAX_VALUES[field_name]) - self.first
+        if self.step and self.step > value_range:
+            raise ValueError('the step value ({}) is higher than the total range of the '
+                             'expression ({})'.format(self.step, value_range))
+
     def get_next_value(self, date, field):
-        start = field.get_value(date)
+        startval = field.get_value(date)
         minval = field.get_min(date)
         maxval = field.get_max(date)
 
         # Apply range limits
         minval = max(minval, self.first)
-        if self.last is not None:
+        maxval = min(maxval, self.last) if self.last is not None else maxval
-            maxval = min(maxval, self.last)
+        nextval = max(minval, startval)
-        start = max(start, minval)
 
-        if not self.step:
+        # Apply the step if defined
-            next = start
+        if self.step:
-        else:
+            distance_to_next = (self.step - (nextval - minval)) % self.step
-            distance_to_next = (self.step - (start - minval)) % self.step
+            nextval += distance_to_next
-            next = start + distance_to_next
 
-        if next <= maxval:
+        return nextval if nextval <= maxval else None
-            return next
+
+    def __eq__(self, other):
+        return (isinstance(other, self.__class__) and self.first == other.first and
+                self.last == other.last)
 
     def __str__(self):
         if self.last != self.first and self.last is not None:
@@ -100,6 +126,37 @@ class RangeExpression(AllExpression):
         return "%s(%s)" % (self.__class__.__name__, ', '.join(args))
 
 
+class MonthRangeExpression(RangeExpression):
+    value_re = re.compile(r'(?P<first>[a-z]+)(?:-(?P<last>[a-z]+))?', re.IGNORECASE)
+
+    def __init__(self, first, last=None):
+        try:
+            first_num = MONTHS.index(first.lower()) + 1
+        except ValueError:
+            raise ValueError('Invalid month name "%s"' % first)
+
+        if last:
+            try:
+                last_num = MONTHS.index(last.lower()) + 1
+            except ValueError:
+                raise ValueError('Invalid month name "%s"' % last)
+        else:
+            last_num = None
+
+        super(MonthRangeExpression, self).__init__(first_num, last_num)
+
+    def __str__(self):
+        if self.last != self.first and self.last is not None:
+            return '%s-%s' % (MONTHS[self.first - 1], MONTHS[self.last - 1])
+        return MONTHS[self.first - 1]
+
+    def __repr__(self):
+        args = ["'%s'" % MONTHS[self.first]]
+        if self.last != self.first and self.last is not None:
+            args.append("'%s'" % MONTHS[self.last - 1])
+        return "%s(%s)" % (self.__class__.__name__, ', '.join(args))
+
+
 class WeekdayRangeExpression(RangeExpression):
     value_re = re.compile(r'(?P<first>[a-z]+)(?:-(?P<last>[a-z]+))?', re.IGNORECASE)
 
@@ -117,7 +174,7 @@ class WeekdayRangeExpression(RangeExpression):
         else:
             last_num = None
 
-        RangeExpression.__init__(self, first_num, last_num)
+        super(WeekdayRangeExpression, self).__init__(first_num, last_num)
 
     def __str__(self):
         if self.last != self.first and self.last is not None:
@@ -133,9 +190,11 @@ class WeekdayRangeExpression(RangeExpression):
 
 class WeekdayPositionExpression(AllExpression):
     options = ['1st', '2nd', '3rd', '4th', '5th', 'last']
-    value_re = re.compile(r'(?P<option_name>%s) +(?P<weekday_name>(?:\d+|\w+))' % '|'.join(options), re.IGNORECASE)
+    value_re = re.compile(r'(?P<option_name>%s) +(?P<weekday_name>(?:\d+|\w+))' %
+                          '|'.join(options), re.IGNORECASE)
 
     def __init__(self, option_name, weekday_name):
+        super(WeekdayPositionExpression, self).__init__(None)
         try:
             self.option_num = self.options.index(option_name.lower())
         except ValueError:
@@ -147,8 +206,7 @@ class WeekdayPositionExpression(AllExpression):
             raise ValueError('Invalid weekday name "%s"' % weekday_name)
 
     def get_next_value(self, date, field):
-        # Figure out the weekday of the month's first day and the number
+        # Figure out the weekday of the month's first day and the number of days in that month
-        # of days in that month
         first_day_wday, last_day = monthrange(date.year, date.month)
 
         # Calculate which day of the month is the first of the target weekdays
@@ -160,23 +218,28 @@ class WeekdayPositionExpression(AllExpression):
         if self.option_num < 5:
             target_day = first_hit_day + self.option_num * 7
         else:
-            target_day = first_hit_day + ((last_day - first_hit_day) / 7) * 7
+            target_day = first_hit_day + ((last_day - first_hit_day) // 7) * 7
 
         if target_day <= last_day and target_day >= date.day:
             return target_day
 
+    def __eq__(self, other):
+        return (super(WeekdayPositionExpression, self).__eq__(other) and
+                self.option_num == other.option_num and self.weekday == other.weekday)
+
     def __str__(self):
         return '%s %s' % (self.options[self.option_num], WEEKDAYS[self.weekday])
 
     def __repr__(self):
-        return "%s('%s', '%s')" % (self.__class__.__name__, self.options[self.option_num], WEEKDAYS[self.weekday])
+        return "%s('%s', '%s')" % (self.__class__.__name__, self.options[self.option_num],
+                                   WEEKDAYS[self.weekday])
 
 
 class LastDayOfMonthExpression(AllExpression):
     value_re = re.compile(r'last', re.IGNORECASE)
 
     def __init__(self):
-        pass
+        super(LastDayOfMonthExpression, self).__init__(None)
 
     def get_next_value(self, date, field):
         return monthrange(date.year, date.month)[1]

lib/apscheduler/triggers/cron/fields.py

@@ -1,22 +1,26 @@
-"""
+"""Fields represent CronTrigger options which map to :class:`~datetime.datetime` fields."""
-Fields represent CronTrigger options which map to :class:`~datetime.datetime`
-fields.
-"""
 
 from calendar import monthrange
+import re
+
+import six
 
 from apscheduler.triggers.cron.expressions import (
-    AllExpression, RangeExpression, WeekdayPositionExpression, LastDayOfMonthExpression, WeekdayRangeExpression)
+    AllExpression, RangeExpression, WeekdayPositionExpression, LastDayOfMonthExpression,
+    WeekdayRangeExpression, MonthRangeExpression)
 
 
-__all__ = ('MIN_VALUES', 'MAX_VALUES', 'DEFAULT_VALUES', 'BaseField', 'WeekField', 'DayOfMonthField', 'DayOfWeekField')
+__all__ = ('MIN_VALUES', 'MAX_VALUES', 'DEFAULT_VALUES', 'BaseField', 'WeekField',
+           'DayOfMonthField', 'DayOfWeekField')
 
 
-MIN_VALUES = {'year': 1970, 'month': 1, 'day': 1, 'week': 1, 'day_of_week': 0, 'hour': 0, 'minute': 0, 'second': 0}
+MIN_VALUES = {'year': 1970, 'month': 1, 'day': 1, 'week': 1, 'day_of_week': 0, 'hour': 0,
-MAX_VALUES = {'year': 2 ** 63, 'month': 12, 'day:': 31, 'week': 53, 'day_of_week': 6, 'hour': 23, 'minute': 59,
+              'minute': 0, 'second': 0}
-              'second': 59}
+MAX_VALUES = {'year': 9999, 'month': 12, 'day': 31, 'week': 53, 'day_of_week': 6, 'hour': 23,
-DEFAULT_VALUES = {'year': '*', 'month': 1, 'day': 1, 'week': '*', 'day_of_week': '*', 'hour': 0, 'minute': 0,
+              'minute': 59, 'second': 59}
-                  'second': 0}
+DEFAULT_VALUES = {'year': '*', 'month': 1, 'day': 1, 'week': '*', 'day_of_week': '*', 'hour': 0,
+                  'minute': 0, 'second': 0}
+SEPARATOR = re.compile(' *, *')
 
 
 class BaseField(object):
@@ -50,23 +54,29 @@ class BaseField(object):
         self.expressions = []
 
         # Split a comma-separated expression list, if any
-        exprs = str(exprs).strip()
+        for expr in SEPARATOR.split(str(exprs).strip()):
-        if ',' in exprs:
-            for expr in exprs.split(','):
             self.compile_expression(expr)
-        else:
-            self.compile_expression(exprs)
 
     def compile_expression(self, expr):
         for compiler in self.COMPILERS:
             match = compiler.value_re.match(expr)
             if match:
                 compiled_expr = compiler(**match.groupdict())
+
+                try:
+                    compiled_expr.validate_range(self.name)
+                except ValueError as e:
+                    exc = ValueError('Error validating expression {!r}: {}'.format(expr, e))
+                    six.raise_from(exc, None)
+
                 self.expressions.append(compiled_expr)
                 return
 
         raise ValueError('Unrecognized expression "%s" for field "%s"' % (expr, self.name))
 
+    def __eq__(self, other):
+        return isinstance(self, self.__class__) and self.expressions == other.expressions
+
     def __str__(self):
         expr_strings = (str(e) for e in self.expressions)
         return ','.join(expr_strings)
@@ -95,3 +105,7 @@ class DayOfWeekField(BaseField):
 
     def get_value(self, dateval):
         return dateval.weekday()
+
+
+class MonthField(BaseField):
+    COMPILERS = BaseField.COMPILERS + [MonthRangeExpression]

lib/apscheduler/triggers/date.py

@@ -14,15 +14,36 @@ class DateTrigger(BaseTrigger):
     :param datetime.tzinfo|str timezone: time zone for ``run_date`` if it doesn't have one already
     """
 
-    __slots__ = 'timezone', 'run_date'
+    __slots__ = 'run_date'
 
     def __init__(self, run_date=None, timezone=None):
         timezone = astimezone(timezone) or get_localzone()
-        self.run_date = convert_to_datetime(run_date or datetime.now(), timezone, 'run_date')
+        if run_date is not None:
+            self.run_date = convert_to_datetime(run_date, timezone, 'run_date')
+        else:
+            self.run_date = datetime.now(timezone)
 
     def get_next_fire_time(self, previous_fire_time, now):
         return self.run_date if previous_fire_time is None else None
 
+    def __getstate__(self):
+        return {
+            'version': 1,
+            'run_date': self.run_date
+        }
+
+    def __setstate__(self, state):
+        # This is for compatibility with APScheduler 3.0.x
+        if isinstance(state, tuple):
+            state = state[1]
+
+        if state.get('version', 1) > 1:
+            raise ValueError(
+                'Got serialized data for version %s of %s, but only version 1 can be handled' %
+                (state['version'], self.__class__.__name__))
+
+        self.run_date = state['run_date']
+
     def __str__(self):
         return 'date[%s]' % datetime_repr(self.run_date)
 

lib/apscheduler/triggers/interval.py

@@ -9,8 +9,8 @@ from apscheduler.util import convert_to_datetime, timedelta_seconds, datetime_re
 
 class IntervalTrigger(BaseTrigger):
     """
-    Triggers on specified intervals, starting on ``start_date`` if specified, ``datetime.now()`` + interval
+    Triggers on specified intervals, starting on ``start_date`` if specified, ``datetime.now()`` +
-    otherwise.
+    interval otherwise.
 
     :param int weeks: number of weeks to wait
     :param int days: number of days to wait
@@ -20,12 +20,15 @@ class IntervalTrigger(BaseTrigger):
     :param datetime|str start_date: starting point for the interval calculation
     :param datetime|str end_date: latest possible date/time to trigger on
     :param datetime.tzinfo|str timezone: time zone to use for the date/time calculations
+    :param int|None jitter: advance or delay the job execution by ``jitter`` seconds at most.
     """
 
-    __slots__ = 'timezone', 'start_date', 'end_date', 'interval'
+    __slots__ = 'timezone', 'start_date', 'end_date', 'interval', 'interval_length', 'jitter'
 
-    def __init__(self, weeks=0, days=0, hours=0, minutes=0, seconds=0, start_date=None, end_date=None, timezone=None):
+    def __init__(self, weeks=0, days=0, hours=0, minutes=0, seconds=0, start_date=None,
-        self.interval = timedelta(weeks=weeks, days=days, hours=hours, minutes=minutes, seconds=seconds)
+                 end_date=None, timezone=None, jitter=None):
+        self.interval = timedelta(weeks=weeks, days=days, hours=hours, minutes=minutes,
+                                  seconds=seconds)
         self.interval_length = timedelta_seconds(self.interval)
         if self.interval_length == 0:
             self.interval = timedelta(seconds=1)
@@ -33,9 +36,9 @@ class IntervalTrigger(BaseTrigger):
 
         if timezone:
             self.timezone = astimezone(timezone)
-        elif start_date and start_date.tzinfo:
+        elif isinstance(start_date, datetime) and start_date.tzinfo:
             self.timezone = start_date.tzinfo
-        elif end_date and end_date.tzinfo:
+        elif isinstance(end_date, datetime) and end_date.tzinfo:
             self.timezone = end_date.tzinfo
         else:
             self.timezone = get_localzone()
@@ -44,6 +47,8 @@ class IntervalTrigger(BaseTrigger):
         self.start_date = convert_to_datetime(start_date, self.timezone, 'start_date')
         self.end_date = convert_to_datetime(end_date, self.timezone, 'end_date')
 
+        self.jitter = jitter
+
     def get_next_fire_time(self, previous_fire_time, now):
         if previous_fire_time:
             next_fire_time = previous_fire_time + self.interval
@@ -54,12 +59,48 @@ class IntervalTrigger(BaseTrigger):
             next_interval_num = int(ceil(timediff_seconds / self.interval_length))
             next_fire_time = self.start_date + self.interval * next_interval_num
 
+        if self.jitter is not None:
+            next_fire_time = self._apply_jitter(next_fire_time, self.jitter, now)
+
         if not self.end_date or next_fire_time <= self.end_date:
             return self.timezone.normalize(next_fire_time)
 
+    def __getstate__(self):
+        return {
+            'version': 2,
+            'timezone': self.timezone,
+            'start_date': self.start_date,
+            'end_date': self.end_date,
+            'interval': self.interval,
+            'jitter': self.jitter,
+        }
+
+    def __setstate__(self, state):
+        # This is for compatibility with APScheduler 3.0.x
+        if isinstance(state, tuple):
+            state = state[1]
+
+        if state.get('version', 1) > 2:
+            raise ValueError(
+                'Got serialized data for version %s of %s, but only versions up to 2 can be '
+                'handled' % (state['version'], self.__class__.__name__))
+
+        self.timezone = state['timezone']
+        self.start_date = state['start_date']
+        self.end_date = state['end_date']
+        self.interval = state['interval']
+        self.interval_length = timedelta_seconds(self.interval)
+        self.jitter = state.get('jitter')
+
     def __str__(self):
         return 'interval[%s]' % str(self.interval)
 
     def __repr__(self):
-        return "<%s (interval=%r, start_date='%s')>" % (self.__class__.__name__, self.interval,
+        options = ['interval=%r' % self.interval, 'start_date=%r' % datetime_repr(self.start_date)]
-                                                        datetime_repr(self.start_date))
+        if self.end_date:
+            options.append("end_date=%r" % datetime_repr(self.end_date))
+        if self.jitter:
+            options.append('jitter=%s' % self.jitter)
+
+        return "<%s (%s, timezone='%s')>" % (
+            self.__class__.__name__, ', '.join(options), self.timezone)

lib/apscheduler/util.py

@@ -2,9 +2,9 @@
 
 from __future__ import division
 from datetime import date, datetime, time, timedelta, tzinfo
-from inspect import isfunction, ismethod, getargspec
 from calendar import timegm
 import re
+from functools import partial
 
 from pytz import timezone, utc
 import six
@@ -12,14 +12,16 @@ import six
 try:
     from inspect import signature
 except ImportError:  # pragma: nocover
-    try:
     from funcsigs import signature
-    except ImportError:
+
-        signature = None
+try:
+    from threading import TIMEOUT_MAX
+except ImportError:
+    TIMEOUT_MAX = 4294967  # Maximum value accepted by Event.wait() on Windows
 
 __all__ = ('asint', 'asbool', 'astimezone', 'convert_to_datetime', 'datetime_to_utc_timestamp',
-           'utc_timestamp_to_datetime', 'timedelta_seconds', 'datetime_ceil', 'get_callable_name', 'obj_to_ref',
+           'utc_timestamp_to_datetime', 'timedelta_seconds', 'datetime_ceil', 'get_callable_name',
-           'ref_to_obj', 'maybe_ref', 'repr_escape', 'check_callable_args')
+           'obj_to_ref', 'ref_to_obj', 'maybe_ref', 'repr_escape', 'check_callable_args')
 
 
 class _Undefined(object):
@@ -32,17 +34,18 @@ class _Undefined(object):
     def __repr__(self):
         return '<undefined>'
 
+
 undefined = _Undefined()  #: a unique object that only signifies that no value is defined
 
 
 def asint(text):
     """
-    Safely converts a string to an integer, returning None if the string is None.
+    Safely converts a string to an integer, returning ``None`` if the string is ``None``.
 
     :type text: str
     :rtype: int
-    """
 
+    """
     if text is not None:
         return int(text)
 
@@ -52,8 +55,8 @@ def asbool(obj):
     Interprets an object as a boolean value.
 
     :rtype: bool
-    """
 
+    """
     if isinstance(obj, str):
         obj = obj.strip().lower()
         if obj in ('true', 'yes', 'on', 'y', 't', '1'):
@@ -69,15 +72,19 @@ def astimezone(obj):
     Interprets an object as a timezone.
 
     :rtype: tzinfo
-    """
 
+    """
     if isinstance(obj, six.string_types):
         return timezone(obj)
     if isinstance(obj, tzinfo):
         if not hasattr(obj, 'localize') or not hasattr(obj, 'normalize'):
             raise TypeError('Only timezones from the pytz library are supported')
         if obj.zone == 'local':
-            raise ValueError('Unable to determine the name of the local timezone -- use an explicit timezone instead')
+            raise ValueError(
+                'Unable to determine the name of the local timezone -- you must explicitly '
+                'specify the name of the local timezone. Please refrain from using timezones like '
+                'EST to prevent problems with daylight saving time. Instead, use a locale based '
+                'timezone name (such as Europe/Helsinki).')
         return obj
     if obj is not None:
         raise TypeError('Expected tzinfo, got %s instead' % obj.__class__.__name__)
@@ -92,20 +99,20 @@ _DATE_REGEX = re.compile(
 def convert_to_datetime(input, tz, arg_name):
     """
     Converts the given object to a timezone aware datetime object.
+
     If a timezone aware datetime object is passed, it is returned unmodified.
     If a native datetime object is passed, it is given the specified timezone.
     If the input is a string, it is parsed as a datetime with the given timezone.
 
-    Date strings are accepted in three different forms: date only (Y-m-d),
+    Date strings are accepted in three different forms: date only (Y-m-d), date with time
-    date with time (Y-m-d H:M:S) or with date+time with microseconds
+    (Y-m-d H:M:S) or with date+time with microseconds (Y-m-d H:M:S.micro).
-    (Y-m-d H:M:S.micro).
 
     :param str|datetime input: the datetime or string to convert to a timezone aware datetime
     :param datetime.tzinfo tz: timezone to interpret ``input`` in
     :param str arg_name: the name of the argument (used in an error message)
     :rtype: datetime
-    """
 
+    """
     if input is None:
         return
     elif isinstance(input, datetime):
@@ -125,14 +132,16 @@ def convert_to_datetime(input, tz, arg_name):
     if datetime_.tzinfo is not None:
         return datetime_
     if tz is None:
-        raise ValueError('The "tz" argument must be specified if %s has no timezone information' % arg_name)
+        raise ValueError(
+            'The "tz" argument must be specified if %s has no timezone information' % arg_name)
     if isinstance(tz, six.string_types):
         tz = timezone(tz)
 
     try:
         return tz.localize(datetime_, is_dst=None)
     except AttributeError:
-        raise TypeError('Only pytz timezones are supported (need the localize() and normalize() methods)')
+        raise TypeError(
+            'Only pytz timezones are supported (need the localize() and normalize() methods)')
 
 
 def datetime_to_utc_timestamp(timeval):
@@ -141,8 +150,8 @@ def datetime_to_utc_timestamp(timeval):
 
     :type timeval: datetime
     :rtype: float
-    """
 
+    """
     if timeval is not None:
         return timegm(timeval.utctimetuple()) + timeval.microsecond / 1000000
 
@@ -153,8 +162,8 @@ def utc_timestamp_to_datetime(timestamp):
 
     :type timestamp: float
     :rtype: datetime
-    """
 
+    """
     if timestamp is not None:
         return datetime.fromtimestamp(timestamp, utc)
 
@@ -165,8 +174,8 @@ def timedelta_seconds(delta):
 
     :type delta: timedelta
     :rtype: float
-    """
 
+    """
     return delta.days * 24 * 60 * 60 + delta.seconds + \
         delta.microseconds / 1000000.0
 
@@ -176,8 +185,8 @@ def datetime_ceil(dateval):
     Rounds the given datetime object upwards.
 
     :type dateval: datetime
-    """
 
+    """
     if dateval.microsecond > 0:
         return dateval + timedelta(seconds=1, microseconds=-dateval.microsecond)
     return dateval
@@ -192,8 +201,8 @@ def get_callable_name(func):
     Returns the best available display name for the given function/callable.
 
     :rtype: str
-    """
 
+    """
     # the easy case (on Python 3.3+)
     if hasattr(func, '__qualname__'):
         return func.__qualname__
@@ -222,20 +231,24 @@ def get_callable_name(func):
 
 def obj_to_ref(obj):
     """
-    Returns the path to the given object.
+    Returns the path to the given callable.
 
     :rtype: str
+    :raises TypeError: if the given object is not callable
+    :raises ValueError: if the given object is a :class:`~functools.partial`, lambda or a nested
+        function
+
     """
+    if isinstance(obj, partial):
+        raise ValueError('Cannot create a reference to a partial()')
 
-    try:
+    name = get_callable_name(obj)
-        ref = '%s:%s' % (obj.__module__, get_callable_name(obj))
+    if '<lambda>' in name:
-        obj2 = ref_to_obj(ref)
+        raise ValueError('Cannot create a reference to a lambda')
-        if obj != obj2:
+    if '<locals>' in name:
-            raise ValueError
+        raise ValueError('Cannot create a reference to a nested function')
-    except Exception:
-        raise ValueError('Cannot determine the reference to %r' % obj)
 
-    return ref
+    return '%s:%s' % (obj.__module__, name)
 
 
 def ref_to_obj(ref):
@@ -243,8 +256,8 @@ def ref_to_obj(ref):
     Returns the object pointed to by ``ref``.
 
     :type ref: str
-    """
 
+    """
     if not isinstance(ref, six.string_types):
         raise TypeError('References must be strings')
     if ':' not in ref:
@@ -252,12 +265,12 @@ def ref_to_obj(ref):
 
     modulename, rest = ref.split(':', 1)
     try:
-        obj = __import__(modulename)
+        obj = __import__(modulename, fromlist=[rest])
     except ImportError:
         raise LookupError('Error resolving reference %s: could not import module' % ref)
 
     try:
-        for name in modulename.split('.')[1:] + rest.split('.'):
+        for name in rest.split('.'):
             obj = getattr(obj, name)
         return obj
     except Exception:
@@ -268,8 +281,8 @@ def maybe_ref(ref):
     """
     Returns the object that the given reference points to, if it is indeed a reference.
     If it is not a reference, the object is returned as-is.
-    """
 
+    """
     if not isinstance(ref, str):
         return ref
     return ref_to_obj(ref)
@@ -281,7 +294,8 @@ if six.PY2:
             return string.encode('ascii', 'backslashreplace')
         return string
 else:
-    repr_escape = lambda string: string
+    def repr_escape(string):
+        return string
 
 
 def check_callable_args(func, args, kwargs):
@@ -290,21 +304,23 @@ def check_callable_args(func, args, kwargs):
 
     :type args: tuple
     :type kwargs: dict
-    """
 
+    """
     pos_kwargs_conflicts = []  # parameters that have a match in both args and kwargs
     positional_only_kwargs = []  # positional-only parameters that have a match in kwargs
     unsatisfied_args = []  # parameters in signature that don't have a match in args or kwargs
     unsatisfied_kwargs = []  # keyword-only arguments that don't have a match in kwargs
     unmatched_args = list(args)  # args that didn't match any of the parameters in the signature
-    unmatched_kwargs = list(kwargs)  # kwargs that didn't match any of the parameters in the signature
+    # kwargs that didn't match any of the parameters in the signature
-    has_varargs = has_var_kwargs = False  # indicates if the signature defines *args and **kwargs respectively
+    unmatched_kwargs = list(kwargs)
+    # indicates if the signature defines *args and **kwargs respectively
+    has_varargs = has_var_kwargs = False
 
-    if signature:
     try:
         sig = signature(func)
     except ValueError:
-            return  # signature() doesn't work against every kind of callable
+        # signature() doesn't work against every kind of callable
+        return
 
     for param in six.itervalues(sig.parameters):
         if param.kind == param.POSITIONAL_OR_KEYWORD:
@@ -333,27 +349,6 @@ def check_callable_args(func, args, kwargs):
             has_varargs = True
         elif param.kind == param.VAR_KEYWORD:
             has_var_kwargs = True
-    else:
-        if not isfunction(func) and not ismethod(func) and hasattr(func, '__call__'):
-            func = func.__call__
-
-        try:
-            argspec = getargspec(func)
-        except TypeError:
-            return  # getargspec() doesn't work certain callables
-
-        argspec_args = argspec.args if not ismethod(func) else argspec.args[1:]
-        has_varargs = bool(argspec.varargs)
-        has_var_kwargs = bool(argspec.keywords)
-        for arg, default in six.moves.zip_longest(argspec_args, argspec.defaults or (), fillvalue=undefined):
-            if arg in unmatched_kwargs and unmatched_args:
-                pos_kwargs_conflicts.append(arg)
-            elif unmatched_args:
-                del unmatched_args[0]
-            elif arg in unmatched_kwargs:
-                unmatched_kwargs.remove(arg)
-            elif default is undefined:
-                unsatisfied_args.append(arg)
 
     # Make sure there are no conflicts between args and kwargs
     if pos_kwargs_conflicts:
@@ -365,21 +360,26 @@ def check_callable_args(func, args, kwargs):
         raise ValueError('The following arguments cannot be given as keyword arguments: %s' %
                          ', '.join(positional_only_kwargs))
 
-    # Check that the number of positional arguments minus the number of matched kwargs matches the argspec
+    # Check that the number of positional arguments minus the number of matched kwargs matches the
+    # argspec
     if unsatisfied_args:
-        raise ValueError('The following arguments have not been supplied: %s' % ', '.join(unsatisfied_args))
+        raise ValueError('The following arguments have not been supplied: %s' %
+                         ', '.join(unsatisfied_args))
 
     # Check that all keyword-only arguments have been supplied
     if unsatisfied_kwargs:
-        raise ValueError('The following keyword-only arguments have not been supplied in kwargs: %s' %
+        raise ValueError(
+            'The following keyword-only arguments have not been supplied in kwargs: %s' %
             ', '.join(unsatisfied_kwargs))
 
     # Check that the callable can accept the given number of positional arguments
     if not has_varargs and unmatched_args:
-        raise ValueError('The list of positional arguments is longer than the target callable can handle '
+        raise ValueError(
+            'The list of positional arguments is longer than the target callable can handle '
             '(allowed: %d, given in args: %d)' % (len(args) - len(unmatched_args), len(args)))
 
     # Check that the callable can accept the given keyword arguments
     if not has_var_kwargs and unmatched_kwargs:
-        raise ValueError('The target callable does not accept the following keyword arguments: %s' %
+        raise ValueError(
+            'The target callable does not accept the following keyword arguments: %s' %
             ', '.join(unmatched_kwargs))