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"""Site container for an HTTP server.
A Web Site Process Bus object is used to connect applications, servers,
and frameworks with site-wide services such as daemonization, process
reload, signal handling, drop privileges, PID file management, logging
for all of these, and many more.
The 'plugins' module defines a few abstract and concrete services for
use with the bus. Some use tool-specific channels; see the documentation
for each class.
"""
from cherrypy.process.wspbus import bus
from cherrypy.process import plugins, servers

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"""Site services for use with a Web Site Process Bus."""
import os
import re
import signal as _signal
import sys
import time
import threading
from cherrypy._cpcompat import basestring, get_daemon, get_thread_ident
from cherrypy._cpcompat import ntob, set, Timer, SetDaemonProperty
# _module__file__base is used by Autoreload to make
# absolute any filenames retrieved from sys.modules which are not
# already absolute paths. This is to work around Python's quirk
# of importing the startup script and using a relative filename
# for it in sys.modules.
#
# Autoreload examines sys.modules afresh every time it runs. If an application
# changes the current directory by executing os.chdir(), then the next time
# Autoreload runs, it will not be able to find any filenames which are
# not absolute paths, because the current directory is not the same as when the
# module was first imported. Autoreload will then wrongly conclude the file
# has "changed", and initiate the shutdown/re-exec sequence.
# See ticket #917.
# For this workaround to have a decent probability of success, this module
# needs to be imported as early as possible, before the app has much chance
# to change the working directory.
_module__file__base = os.getcwd()
class SimplePlugin(object):
"""Plugin base class which auto-subscribes methods for known channels."""
bus = None
"""A :class:`Bus <cherrypy.process.wspbus.Bus>`, usually cherrypy.engine.
"""
def __init__(self, bus):
self.bus = bus
def subscribe(self):
"""Register this object as a (multi-channel) listener on the bus."""
for channel in self.bus.listeners:
# Subscribe self.start, self.exit, etc. if present.
method = getattr(self, channel, None)
if method is not None:
self.bus.subscribe(channel, method)
def unsubscribe(self):
"""Unregister this object as a listener on the bus."""
for channel in self.bus.listeners:
# Unsubscribe self.start, self.exit, etc. if present.
method = getattr(self, channel, None)
if method is not None:
self.bus.unsubscribe(channel, method)
class SignalHandler(object):
"""Register bus channels (and listeners) for system signals.
You can modify what signals your application listens for, and what it does
when it receives signals, by modifying :attr:`SignalHandler.handlers`,
a dict of {signal name: callback} pairs. The default set is::
handlers = {'SIGTERM': self.bus.exit,
'SIGHUP': self.handle_SIGHUP,
'SIGUSR1': self.bus.graceful,
}
The :func:`SignalHandler.handle_SIGHUP`` method calls
:func:`bus.restart()<cherrypy.process.wspbus.Bus.restart>`
if the process is daemonized, but
:func:`bus.exit()<cherrypy.process.wspbus.Bus.exit>`
if the process is attached to a TTY. This is because Unix window
managers tend to send SIGHUP to terminal windows when the user closes them.
Feel free to add signals which are not available on every platform.
The :class:`SignalHandler` will ignore errors raised from attempting
to register handlers for unknown signals.
"""
handlers = {}
"""A map from signal names (e.g. 'SIGTERM') to handlers (e.g. bus.exit)."""
signals = {}
"""A map from signal numbers to names."""
for k, v in vars(_signal).items():
if k.startswith('SIG') and not k.startswith('SIG_'):
signals[v] = k
del k, v
def __init__(self, bus):
self.bus = bus
# Set default handlers
self.handlers = {'SIGTERM': self.bus.exit,
'SIGHUP': self.handle_SIGHUP,
'SIGUSR1': self.bus.graceful,
}
if sys.platform[:4] == 'java':
del self.handlers['SIGUSR1']
self.handlers['SIGUSR2'] = self.bus.graceful
self.bus.log("SIGUSR1 cannot be set on the JVM platform. "
"Using SIGUSR2 instead.")
self.handlers['SIGINT'] = self._jython_SIGINT_handler
self._previous_handlers = {}
def _jython_SIGINT_handler(self, signum=None, frame=None):
# See http://bugs.jython.org/issue1313
self.bus.log('Keyboard Interrupt: shutting down bus')
self.bus.exit()
def subscribe(self):
"""Subscribe self.handlers to signals."""
for sig, func in self.handlers.items():
try:
self.set_handler(sig, func)
except ValueError:
pass
def unsubscribe(self):
"""Unsubscribe self.handlers from signals."""
for signum, handler in self._previous_handlers.items():
signame = self.signals[signum]
if handler is None:
self.bus.log("Restoring %s handler to SIG_DFL." % signame)
handler = _signal.SIG_DFL
else:
self.bus.log("Restoring %s handler %r." % (signame, handler))
try:
our_handler = _signal.signal(signum, handler)
if our_handler is None:
self.bus.log("Restored old %s handler %r, but our "
"handler was not registered." %
(signame, handler), level=30)
except ValueError:
self.bus.log("Unable to restore %s handler %r." %
(signame, handler), level=40, traceback=True)
def set_handler(self, signal, listener=None):
"""Subscribe a handler for the given signal (number or name).
If the optional 'listener' argument is provided, it will be
subscribed as a listener for the given signal's channel.
If the given signal name or number is not available on the current
platform, ValueError is raised.
"""
if isinstance(signal, basestring):
signum = getattr(_signal, signal, None)
if signum is None:
raise ValueError("No such signal: %r" % signal)
signame = signal
else:
try:
signame = self.signals[signal]
except KeyError:
raise ValueError("No such signal: %r" % signal)
signum = signal
prev = _signal.signal(signum, self._handle_signal)
self._previous_handlers[signum] = prev
if listener is not None:
self.bus.log("Listening for %s." % signame)
self.bus.subscribe(signame, listener)
def _handle_signal(self, signum=None, frame=None):
"""Python signal handler (self.set_handler subscribes it for you)."""
signame = self.signals[signum]
self.bus.log("Caught signal %s." % signame)
self.bus.publish(signame)
def handle_SIGHUP(self):
"""Restart if daemonized, else exit."""
if os.isatty(sys.stdin.fileno()):
# not daemonized (may be foreground or background)
self.bus.log("SIGHUP caught but not daemonized. Exiting.")
self.bus.exit()
else:
self.bus.log("SIGHUP caught while daemonized. Restarting.")
self.bus.restart()
try:
import pwd
import grp
except ImportError:
pwd, grp = None, None
class DropPrivileges(SimplePlugin):
"""Drop privileges. uid/gid arguments not available on Windows.
Special thanks to `Gavin Baker <http://antonym.org/2005/12/dropping-privileges-in-python.html>`_
"""
def __init__(self, bus, umask=None, uid=None, gid=None):
SimplePlugin.__init__(self, bus)
self.finalized = False
self.uid = uid
self.gid = gid
self.umask = umask
def _get_uid(self):
return self._uid
def _set_uid(self, val):
if val is not None:
if pwd is None:
self.bus.log("pwd module not available; ignoring uid.",
level=30)
val = None
elif isinstance(val, basestring):
val = pwd.getpwnam(val)[2]
self._uid = val
uid = property(_get_uid, _set_uid,
doc="The uid under which to run. Availability: Unix.")
def _get_gid(self):
return self._gid
def _set_gid(self, val):
if val is not None:
if grp is None:
self.bus.log("grp module not available; ignoring gid.",
level=30)
val = None
elif isinstance(val, basestring):
val = grp.getgrnam(val)[2]
self._gid = val
gid = property(_get_gid, _set_gid,
doc="The gid under which to run. Availability: Unix.")
def _get_umask(self):
return self._umask
def _set_umask(self, val):
if val is not None:
try:
os.umask
except AttributeError:
self.bus.log("umask function not available; ignoring umask.",
level=30)
val = None
self._umask = val
umask = property(
_get_umask,
_set_umask,
doc="""The default permission mode for newly created files and
directories.
Usually expressed in octal format, for example, ``0644``.
Availability: Unix, Windows.
""")
def start(self):
# uid/gid
def current_ids():
"""Return the current (uid, gid) if available."""
name, group = None, None
if pwd:
name = pwd.getpwuid(os.getuid())[0]
if grp:
group = grp.getgrgid(os.getgid())[0]
return name, group
if self.finalized:
if not (self.uid is None and self.gid is None):
self.bus.log('Already running as uid: %r gid: %r' %
current_ids())
else:
if self.uid is None and self.gid is None:
if pwd or grp:
self.bus.log('uid/gid not set', level=30)
else:
self.bus.log('Started as uid: %r gid: %r' % current_ids())
if self.gid is not None:
os.setgid(self.gid)
os.setgroups([])
if self.uid is not None:
os.setuid(self.uid)
self.bus.log('Running as uid: %r gid: %r' % current_ids())
# umask
if self.finalized:
if self.umask is not None:
self.bus.log('umask already set to: %03o' % self.umask)
else:
if self.umask is None:
self.bus.log('umask not set', level=30)
else:
old_umask = os.umask(self.umask)
self.bus.log('umask old: %03o, new: %03o' %
(old_umask, self.umask))
self.finalized = True
# This is slightly higher than the priority for server.start
# in order to facilitate the most common use: starting on a low
# port (which requires root) and then dropping to another user.
start.priority = 77
class Daemonizer(SimplePlugin):
"""Daemonize the running script.
Use this with a Web Site Process Bus via::
Daemonizer(bus).subscribe()
When this component finishes, the process is completely decoupled from
the parent environment. Please note that when this component is used,
the return code from the parent process will still be 0 if a startup
error occurs in the forked children. Errors in the initial daemonizing
process still return proper exit codes. Therefore, if you use this
plugin to daemonize, don't use the return code as an accurate indicator
of whether the process fully started. In fact, that return code only
indicates if the process succesfully finished the first fork.
"""
def __init__(self, bus, stdin='/dev/null', stdout='/dev/null',
stderr='/dev/null'):
SimplePlugin.__init__(self, bus)
self.stdin = stdin
self.stdout = stdout
self.stderr = stderr
self.finalized = False
def start(self):
if self.finalized:
self.bus.log('Already deamonized.')
# forking has issues with threads:
# http://www.opengroup.org/onlinepubs/000095399/functions/fork.html
# "The general problem with making fork() work in a multi-threaded
# world is what to do with all of the threads..."
# So we check for active threads:
if threading.activeCount() != 1:
self.bus.log('There are %r active threads. '
'Daemonizing now may cause strange failures.' %
threading.enumerate(), level=30)
# See http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
# (or http://www.faqs.org/faqs/unix-faq/programmer/faq/ section 1.7)
# and http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66012
# Finish up with the current stdout/stderr
sys.stdout.flush()
sys.stderr.flush()
# Do first fork.
try:
pid = os.fork()
if pid == 0:
# This is the child process. Continue.
pass
else:
# This is the first parent. Exit, now that we've forked.
self.bus.log('Forking once.')
os._exit(0)
except OSError:
# Python raises OSError rather than returning negative numbers.
exc = sys.exc_info()[1]
sys.exit("%s: fork #1 failed: (%d) %s\n"
% (sys.argv[0], exc.errno, exc.strerror))
os.setsid()
# Do second fork
try:
pid = os.fork()
if pid > 0:
self.bus.log('Forking twice.')
os._exit(0) # Exit second parent
except OSError:
exc = sys.exc_info()[1]
sys.exit("%s: fork #2 failed: (%d) %s\n"
% (sys.argv[0], exc.errno, exc.strerror))
os.chdir("/")
os.umask(0)
si = open(self.stdin, "r")
so = open(self.stdout, "a+")
se = open(self.stderr, "a+")
# os.dup2(fd, fd2) will close fd2 if necessary,
# so we don't explicitly close stdin/out/err.
# See http://docs.python.org/lib/os-fd-ops.html
os.dup2(si.fileno(), sys.stdin.fileno())
os.dup2(so.fileno(), sys.stdout.fileno())
os.dup2(se.fileno(), sys.stderr.fileno())
self.bus.log('Daemonized to PID: %s' % os.getpid())
self.finalized = True
start.priority = 65
class PIDFile(SimplePlugin):
"""Maintain a PID file via a WSPBus."""
def __init__(self, bus, pidfile):
SimplePlugin.__init__(self, bus)
self.pidfile = pidfile
self.finalized = False
def start(self):
pid = os.getpid()
if self.finalized:
self.bus.log('PID %r already written to %r.' % (pid, self.pidfile))
else:
open(self.pidfile, "wb").write(ntob("%s\n" % pid, 'utf8'))
self.bus.log('PID %r written to %r.' % (pid, self.pidfile))
self.finalized = True
start.priority = 70
def exit(self):
try:
os.remove(self.pidfile)
self.bus.log('PID file removed: %r.' % self.pidfile)
except (KeyboardInterrupt, SystemExit):
raise
except:
pass
class PerpetualTimer(Timer):
"""A responsive subclass of threading.Timer whose run() method repeats.
Use this timer only when you really need a very interruptible timer;
this checks its 'finished' condition up to 20 times a second, which can
results in pretty high CPU usage
"""
def __init__(self, *args, **kwargs):
"Override parent constructor to allow 'bus' to be provided."
self.bus = kwargs.pop('bus', None)
super(PerpetualTimer, self).__init__(*args, **kwargs)
def run(self):
while True:
self.finished.wait(self.interval)
if self.finished.isSet():
return
try:
self.function(*self.args, **self.kwargs)
except Exception:
if self.bus:
self.bus.log(
"Error in perpetual timer thread function %r." %
self.function, level=40, traceback=True)
# Quit on first error to avoid massive logs.
raise
class BackgroundTask(SetDaemonProperty, threading.Thread):
"""A subclass of threading.Thread whose run() method repeats.
Use this class for most repeating tasks. It uses time.sleep() to wait
for each interval, which isn't very responsive; that is, even if you call
self.cancel(), you'll have to wait until the sleep() call finishes before
the thread stops. To compensate, it defaults to being daemonic, which means
it won't delay stopping the whole process.
"""
def __init__(self, interval, function, args=[], kwargs={}, bus=None):
threading.Thread.__init__(self)
self.interval = interval
self.function = function
self.args = args
self.kwargs = kwargs
self.running = False
self.bus = bus
# default to daemonic
self.daemon = True
def cancel(self):
self.running = False
def run(self):
self.running = True
while self.running:
time.sleep(self.interval)
if not self.running:
return
try:
self.function(*self.args, **self.kwargs)
except Exception:
if self.bus:
self.bus.log("Error in background task thread function %r."
% self.function, level=40, traceback=True)
# Quit on first error to avoid massive logs.
raise
class Monitor(SimplePlugin):
"""WSPBus listener to periodically run a callback in its own thread."""
callback = None
"""The function to call at intervals."""
frequency = 60
"""The time in seconds between callback runs."""
thread = None
"""A :class:`BackgroundTask<cherrypy.process.plugins.BackgroundTask>`
thread.
"""
def __init__(self, bus, callback, frequency=60, name=None):
SimplePlugin.__init__(self, bus)
self.callback = callback
self.frequency = frequency
self.thread = None
self.name = name
def start(self):
"""Start our callback in its own background thread."""
if self.frequency > 0:
threadname = self.name or self.__class__.__name__
if self.thread is None:
self.thread = BackgroundTask(self.frequency, self.callback,
bus=self.bus)
self.thread.setName(threadname)
self.thread.start()
self.bus.log("Started monitor thread %r." % threadname)
else:
self.bus.log("Monitor thread %r already started." % threadname)
start.priority = 70
def stop(self):
"""Stop our callback's background task thread."""
if self.thread is None:
self.bus.log("No thread running for %s." %
self.name or self.__class__.__name__)
else:
if self.thread is not threading.currentThread():
name = self.thread.getName()
self.thread.cancel()
if not get_daemon(self.thread):
self.bus.log("Joining %r" % name)
self.thread.join()
self.bus.log("Stopped thread %r." % name)
self.thread = None
def graceful(self):
"""Stop the callback's background task thread and restart it."""
self.stop()
self.start()
class Autoreloader(Monitor):
"""Monitor which re-executes the process when files change.
This :ref:`plugin<plugins>` restarts the process (via :func:`os.execv`)
if any of the files it monitors change (or is deleted). By default, the
autoreloader monitors all imported modules; you can add to the
set by adding to ``autoreload.files``::
cherrypy.engine.autoreload.files.add(myFile)
If there are imported files you do *not* wish to monitor, you can
adjust the ``match`` attribute, a regular expression. For example,
to stop monitoring cherrypy itself::
cherrypy.engine.autoreload.match = r'^(?!cherrypy).+'
Like all :class:`Monitor<cherrypy.process.plugins.Monitor>` plugins,
the autoreload plugin takes a ``frequency`` argument. The default is
1 second; that is, the autoreloader will examine files once each second.
"""
files = None
"""The set of files to poll for modifications."""
frequency = 1
"""The interval in seconds at which to poll for modified files."""
match = '.*'
"""A regular expression by which to match filenames."""
def __init__(self, bus, frequency=1, match='.*'):
self.mtimes = {}
self.files = set()
self.match = match
Monitor.__init__(self, bus, self.run, frequency)
def start(self):
"""Start our own background task thread for self.run."""
if self.thread is None:
self.mtimes = {}
Monitor.start(self)
start.priority = 70
def sysfiles(self):
"""Return a Set of sys.modules filenames to monitor."""
files = set()
for k, m in list(sys.modules.items()):
if re.match(self.match, k):
if (
hasattr(m, '__loader__') and
hasattr(m.__loader__, 'archive')
):
f = m.__loader__.archive
else:
f = getattr(m, '__file__', None)
if f is not None and not os.path.isabs(f):
# ensure absolute paths so a os.chdir() in the app
# doesn't break me
f = os.path.normpath(
os.path.join(_module__file__base, f))
files.add(f)
return files
def run(self):
"""Reload the process if registered files have been modified."""
for filename in self.sysfiles() | self.files:
if filename:
if filename.endswith('.pyc'):
filename = filename[:-1]
oldtime = self.mtimes.get(filename, 0)
if oldtime is None:
# Module with no .py file. Skip it.
continue
try:
mtime = os.stat(filename).st_mtime
except OSError:
# Either a module with no .py file, or it's been deleted.
mtime = None
if filename not in self.mtimes:
# If a module has no .py file, this will be None.
self.mtimes[filename] = mtime
else:
if mtime is None or mtime > oldtime:
# The file has been deleted or modified.
self.bus.log("Restarting because %s changed." %
filename)
self.thread.cancel()
self.bus.log("Stopped thread %r." %
self.thread.getName())
self.bus.restart()
return
class ThreadManager(SimplePlugin):
"""Manager for HTTP request threads.
If you have control over thread creation and destruction, publish to
the 'acquire_thread' and 'release_thread' channels (for each thread).
This will register/unregister the current thread and publish to
'start_thread' and 'stop_thread' listeners in the bus as needed.
If threads are created and destroyed by code you do not control
(e.g., Apache), then, at the beginning of every HTTP request,
publish to 'acquire_thread' only. You should not publish to
'release_thread' in this case, since you do not know whether
the thread will be re-used or not. The bus will call
'stop_thread' listeners for you when it stops.
"""
threads = None
"""A map of {thread ident: index number} pairs."""
def __init__(self, bus):
self.threads = {}
SimplePlugin.__init__(self, bus)
self.bus.listeners.setdefault('acquire_thread', set())
self.bus.listeners.setdefault('start_thread', set())
self.bus.listeners.setdefault('release_thread', set())
self.bus.listeners.setdefault('stop_thread', set())
def acquire_thread(self):
"""Run 'start_thread' listeners for the current thread.
If the current thread has already been seen, any 'start_thread'
listeners will not be run again.
"""
thread_ident = get_thread_ident()
if thread_ident not in self.threads:
# We can't just use get_ident as the thread ID
# because some platforms reuse thread ID's.
i = len(self.threads) + 1
self.threads[thread_ident] = i
self.bus.publish('start_thread', i)
def release_thread(self):
"""Release the current thread and run 'stop_thread' listeners."""
thread_ident = get_thread_ident()
i = self.threads.pop(thread_ident, None)
if i is not None:
self.bus.publish('stop_thread', i)
def stop(self):
"""Release all threads and run all 'stop_thread' listeners."""
for thread_ident, i in self.threads.items():
self.bus.publish('stop_thread', i)
self.threads.clear()
graceful = stop

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"""
Starting in CherryPy 3.1, cherrypy.server is implemented as an
:ref:`Engine Plugin<plugins>`. It's an instance of
:class:`cherrypy._cpserver.Server`, which is a subclass of
:class:`cherrypy.process.servers.ServerAdapter`. The ``ServerAdapter`` class
is designed to control other servers, as well.
Multiple servers/ports
======================
If you need to start more than one HTTP server (to serve on multiple ports, or
protocols, etc.), you can manually register each one and then start them all
with engine.start::
s1 = ServerAdapter(cherrypy.engine, MyWSGIServer(host='0.0.0.0', port=80))
s2 = ServerAdapter(cherrypy.engine,
another.HTTPServer(host='127.0.0.1',
SSL=True))
s1.subscribe()
s2.subscribe()
cherrypy.engine.start()
.. index:: SCGI
FastCGI/SCGI
============
There are also Flup\ **F**\ CGIServer and Flup\ **S**\ CGIServer classes in
:mod:`cherrypy.process.servers`. To start an fcgi server, for example,
wrap an instance of it in a ServerAdapter::
addr = ('0.0.0.0', 4000)
f = servers.FlupFCGIServer(application=cherrypy.tree, bindAddress=addr)
s = servers.ServerAdapter(cherrypy.engine, httpserver=f, bind_addr=addr)
s.subscribe()
The :doc:`cherryd</deployguide/cherryd>` startup script will do the above for
you via its `-f` flag.
Note that you need to download and install `flup <http://trac.saddi.com/flup>`_
yourself, whether you use ``cherryd`` or not.
.. _fastcgi:
.. index:: FastCGI
FastCGI
-------
A very simple setup lets your cherry run with FastCGI.
You just need the flup library,
plus a running Apache server (with ``mod_fastcgi``) or lighttpd server.
CherryPy code
^^^^^^^^^^^^^
hello.py::
#!/usr/bin/python
import cherrypy
class HelloWorld:
\"""Sample request handler class.\"""
def index(self):
return "Hello world!"
index.exposed = True
cherrypy.tree.mount(HelloWorld())
# CherryPy autoreload must be disabled for the flup server to work
cherrypy.config.update({'engine.autoreload.on':False})
Then run :doc:`/deployguide/cherryd` with the '-f' arg::
cherryd -c <myconfig> -d -f -i hello.py
Apache
^^^^^^
At the top level in httpd.conf::
FastCgiIpcDir /tmp
FastCgiServer /path/to/cherry.fcgi -idle-timeout 120 -processes 4
And inside the relevant VirtualHost section::
# FastCGI config
AddHandler fastcgi-script .fcgi
ScriptAliasMatch (.*$) /path/to/cherry.fcgi$1
Lighttpd
^^^^^^^^
For `Lighttpd <http://www.lighttpd.net/>`_ you can follow these
instructions. Within ``lighttpd.conf`` make sure ``mod_fastcgi`` is
active within ``server.modules``. Then, within your ``$HTTP["host"]``
directive, configure your fastcgi script like the following::
$HTTP["url"] =~ "" {
fastcgi.server = (
"/" => (
"script.fcgi" => (
"bin-path" => "/path/to/your/script.fcgi",
"socket" => "/tmp/script.sock",
"check-local" => "disable",
"disable-time" => 1,
"min-procs" => 1,
"max-procs" => 1, # adjust as needed
),
),
)
} # end of $HTTP["url"] =~ "^/"
Please see `Lighttpd FastCGI Docs
<http://redmine.lighttpd.net/wiki/lighttpd/Docs:ModFastCGI>`_ for
an explanation of the possible configuration options.
"""
import sys
import time
import warnings
class ServerAdapter(object):
"""Adapter for an HTTP server.
If you need to start more than one HTTP server (to serve on multiple
ports, or protocols, etc.), you can manually register each one and then
start them all with bus.start:
s1 = ServerAdapter(bus, MyWSGIServer(host='0.0.0.0', port=80))
s2 = ServerAdapter(bus, another.HTTPServer(host='127.0.0.1', SSL=True))
s1.subscribe()
s2.subscribe()
bus.start()
"""
def __init__(self, bus, httpserver=None, bind_addr=None):
self.bus = bus
self.httpserver = httpserver
self.bind_addr = bind_addr
self.interrupt = None
self.running = False
def subscribe(self):
self.bus.subscribe('start', self.start)
self.bus.subscribe('stop', self.stop)
def unsubscribe(self):
self.bus.unsubscribe('start', self.start)
self.bus.unsubscribe('stop', self.stop)
def start(self):
"""Start the HTTP server."""
if self.bind_addr is None:
on_what = "unknown interface (dynamic?)"
elif isinstance(self.bind_addr, tuple):
on_what = self._get_base()
else:
on_what = "socket file: %s" % self.bind_addr
if self.running:
self.bus.log("Already serving on %s" % on_what)
return
self.interrupt = None
if not self.httpserver:
raise ValueError("No HTTP server has been created.")
# Start the httpserver in a new thread.
if isinstance(self.bind_addr, tuple):
wait_for_free_port(*self.bind_addr)
import threading
t = threading.Thread(target=self._start_http_thread)
t.setName("HTTPServer " + t.getName())
t.start()
self.wait()
self.running = True
self.bus.log("Serving on %s" % on_what)
start.priority = 75
def _get_base(self):
if not self.httpserver:
return ''
host, port = self.bind_addr
if getattr(self.httpserver, 'ssl_certificate', None):
scheme = "https"
if port != 443:
host += ":%s" % port
else:
scheme = "http"
if port != 80:
host += ":%s" % port
return "%s://%s" % (scheme, host)
def _start_http_thread(self):
"""HTTP servers MUST be running in new threads, so that the
main thread persists to receive KeyboardInterrupt's. If an
exception is raised in the httpserver's thread then it's
trapped here, and the bus (and therefore our httpserver)
are shut down.
"""
try:
self.httpserver.start()
except KeyboardInterrupt:
self.bus.log("<Ctrl-C> hit: shutting down HTTP server")
self.interrupt = sys.exc_info()[1]
self.bus.exit()
except SystemExit:
self.bus.log("SystemExit raised: shutting down HTTP server")
self.interrupt = sys.exc_info()[1]
self.bus.exit()
raise
except:
self.interrupt = sys.exc_info()[1]
self.bus.log("Error in HTTP server: shutting down",
traceback=True, level=40)
self.bus.exit()
raise
def wait(self):
"""Wait until the HTTP server is ready to receive requests."""
while not getattr(self.httpserver, "ready", False):
if self.interrupt:
raise self.interrupt
time.sleep(.1)
# Wait for port to be occupied
if isinstance(self.bind_addr, tuple):
host, port = self.bind_addr
wait_for_occupied_port(host, port)
def stop(self):
"""Stop the HTTP server."""
if self.running:
# stop() MUST block until the server is *truly* stopped.
self.httpserver.stop()
# Wait for the socket to be truly freed.
if isinstance(self.bind_addr, tuple):
wait_for_free_port(*self.bind_addr)
self.running = False
self.bus.log("HTTP Server %s shut down" % self.httpserver)
else:
self.bus.log("HTTP Server %s already shut down" % self.httpserver)
stop.priority = 25
def restart(self):
"""Restart the HTTP server."""
self.stop()
self.start()
class FlupCGIServer(object):
"""Adapter for a flup.server.cgi.WSGIServer."""
def __init__(self, *args, **kwargs):
self.args = args
self.kwargs = kwargs
self.ready = False
def start(self):
"""Start the CGI server."""
# We have to instantiate the server class here because its __init__
# starts a threadpool. If we do it too early, daemonize won't work.
from flup.server.cgi import WSGIServer
self.cgiserver = WSGIServer(*self.args, **self.kwargs)
self.ready = True
self.cgiserver.run()
def stop(self):
"""Stop the HTTP server."""
self.ready = False
class FlupFCGIServer(object):
"""Adapter for a flup.server.fcgi.WSGIServer."""
def __init__(self, *args, **kwargs):
if kwargs.get('bindAddress', None) is None:
import socket
if not hasattr(socket, 'fromfd'):
raise ValueError(
'Dynamic FCGI server not available on this platform. '
'You must use a static or external one by providing a '
'legal bindAddress.')
self.args = args
self.kwargs = kwargs
self.ready = False
def start(self):
"""Start the FCGI server."""
# We have to instantiate the server class here because its __init__
# starts a threadpool. If we do it too early, daemonize won't work.
from flup.server.fcgi import WSGIServer
self.fcgiserver = WSGIServer(*self.args, **self.kwargs)
# TODO: report this bug upstream to flup.
# If we don't set _oldSIGs on Windows, we get:
# File "C:\Python24\Lib\site-packages\flup\server\threadedserver.py",
# line 108, in run
# self._restoreSignalHandlers()
# File "C:\Python24\Lib\site-packages\flup\server\threadedserver.py",
# line 156, in _restoreSignalHandlers
# for signum,handler in self._oldSIGs:
# AttributeError: 'WSGIServer' object has no attribute '_oldSIGs'
self.fcgiserver._installSignalHandlers = lambda: None
self.fcgiserver._oldSIGs = []
self.ready = True
self.fcgiserver.run()
def stop(self):
"""Stop the HTTP server."""
# Forcibly stop the fcgi server main event loop.
self.fcgiserver._keepGoing = False
# Force all worker threads to die off.
self.fcgiserver._threadPool.maxSpare = (
self.fcgiserver._threadPool._idleCount)
self.ready = False
class FlupSCGIServer(object):
"""Adapter for a flup.server.scgi.WSGIServer."""
def __init__(self, *args, **kwargs):
self.args = args
self.kwargs = kwargs
self.ready = False
def start(self):
"""Start the SCGI server."""
# We have to instantiate the server class here because its __init__
# starts a threadpool. If we do it too early, daemonize won't work.
from flup.server.scgi import WSGIServer
self.scgiserver = WSGIServer(*self.args, **self.kwargs)
# TODO: report this bug upstream to flup.
# If we don't set _oldSIGs on Windows, we get:
# File "C:\Python24\Lib\site-packages\flup\server\threadedserver.py",
# line 108, in run
# self._restoreSignalHandlers()
# File "C:\Python24\Lib\site-packages\flup\server\threadedserver.py",
# line 156, in _restoreSignalHandlers
# for signum,handler in self._oldSIGs:
# AttributeError: 'WSGIServer' object has no attribute '_oldSIGs'
self.scgiserver._installSignalHandlers = lambda: None
self.scgiserver._oldSIGs = []
self.ready = True
self.scgiserver.run()
def stop(self):
"""Stop the HTTP server."""
self.ready = False
# Forcibly stop the scgi server main event loop.
self.scgiserver._keepGoing = False
# Force all worker threads to die off.
self.scgiserver._threadPool.maxSpare = 0
def client_host(server_host):
"""Return the host on which a client can connect to the given listener."""
if server_host == '0.0.0.0':
# 0.0.0.0 is INADDR_ANY, which should answer on localhost.
return '127.0.0.1'
if server_host in ('::', '::0', '::0.0.0.0'):
# :: is IN6ADDR_ANY, which should answer on localhost.
# ::0 and ::0.0.0.0 are non-canonical but common
# ways to write IN6ADDR_ANY.
return '::1'
return server_host
def check_port(host, port, timeout=1.0):
"""Raise an error if the given port is not free on the given host."""
if not host:
raise ValueError("Host values of '' or None are not allowed.")
host = client_host(host)
port = int(port)
import socket
# AF_INET or AF_INET6 socket
# Get the correct address family for our host (allows IPv6 addresses)
try:
info = socket.getaddrinfo(host, port, socket.AF_UNSPEC,
socket.SOCK_STREAM)
except socket.gaierror:
if ':' in host:
info = [(
socket.AF_INET6, socket.SOCK_STREAM, 0, "", (host, port, 0, 0)
)]
else:
info = [(socket.AF_INET, socket.SOCK_STREAM, 0, "", (host, port))]
for res in info:
af, socktype, proto, canonname, sa = res
s = None
try:
s = socket.socket(af, socktype, proto)
# See http://groups.google.com/group/cherrypy-users/
# browse_frm/thread/bbfe5eb39c904fe0
s.settimeout(timeout)
s.connect((host, port))
s.close()
except socket.error:
if s:
s.close()
else:
raise IOError("Port %s is in use on %s; perhaps the previous "
"httpserver did not shut down properly." %
(repr(port), repr(host)))
# Feel free to increase these defaults on slow systems:
free_port_timeout = 0.1
occupied_port_timeout = 1.0
def wait_for_free_port(host, port, timeout=None):
"""Wait for the specified port to become free (drop requests)."""
if not host:
raise ValueError("Host values of '' or None are not allowed.")
if timeout is None:
timeout = free_port_timeout
for trial in range(50):
try:
# we are expecting a free port, so reduce the timeout
check_port(host, port, timeout=timeout)
except IOError:
# Give the old server thread time to free the port.
time.sleep(timeout)
else:
return
raise IOError("Port %r not free on %r" % (port, host))
def wait_for_occupied_port(host, port, timeout=None):
"""Wait for the specified port to become active (receive requests)."""
if not host:
raise ValueError("Host values of '' or None are not allowed.")
if timeout is None:
timeout = occupied_port_timeout
for trial in range(50):
try:
check_port(host, port, timeout=timeout)
except IOError:
# port is occupied
return
else:
time.sleep(timeout)
if host == client_host(host):
raise IOError("Port %r not bound on %r" % (port, host))
# On systems where a loopback interface is not available and the
# server is bound to all interfaces, it's difficult to determine
# whether the server is in fact occupying the port. In this case,
# just issue a warning and move on. See issue #1100.
msg = "Unable to verify that the server is bound on %r" % port
warnings.warn(msg)

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"""Windows service. Requires pywin32."""
import os
import win32api
import win32con
import win32event
import win32service
import win32serviceutil
from cherrypy.process import wspbus, plugins
class ConsoleCtrlHandler(plugins.SimplePlugin):
"""A WSPBus plugin for handling Win32 console events (like Ctrl-C)."""
def __init__(self, bus):
self.is_set = False
plugins.SimplePlugin.__init__(self, bus)
def start(self):
if self.is_set:
self.bus.log('Handler for console events already set.', level=40)
return
result = win32api.SetConsoleCtrlHandler(self.handle, 1)
if result == 0:
self.bus.log('Could not SetConsoleCtrlHandler (error %r)' %
win32api.GetLastError(), level=40)
else:
self.bus.log('Set handler for console events.', level=40)
self.is_set = True
def stop(self):
if not self.is_set:
self.bus.log('Handler for console events already off.', level=40)
return
try:
result = win32api.SetConsoleCtrlHandler(self.handle, 0)
except ValueError:
# "ValueError: The object has not been registered"
result = 1
if result == 0:
self.bus.log('Could not remove SetConsoleCtrlHandler (error %r)' %
win32api.GetLastError(), level=40)
else:
self.bus.log('Removed handler for console events.', level=40)
self.is_set = False
def handle(self, event):
"""Handle console control events (like Ctrl-C)."""
if event in (win32con.CTRL_C_EVENT, win32con.CTRL_LOGOFF_EVENT,
win32con.CTRL_BREAK_EVENT, win32con.CTRL_SHUTDOWN_EVENT,
win32con.CTRL_CLOSE_EVENT):
self.bus.log('Console event %s: shutting down bus' % event)
# Remove self immediately so repeated Ctrl-C doesn't re-call it.
try:
self.stop()
except ValueError:
pass
self.bus.exit()
# 'First to return True stops the calls'
return 1
return 0
class Win32Bus(wspbus.Bus):
"""A Web Site Process Bus implementation for Win32.
Instead of time.sleep, this bus blocks using native win32event objects.
"""
def __init__(self):
self.events = {}
wspbus.Bus.__init__(self)
def _get_state_event(self, state):
"""Return a win32event for the given state (creating it if needed)."""
try:
return self.events[state]
except KeyError:
event = win32event.CreateEvent(None, 0, 0,
"WSPBus %s Event (pid=%r)" %
(state.name, os.getpid()))
self.events[state] = event
return event
def _get_state(self):
return self._state
def _set_state(self, value):
self._state = value
event = self._get_state_event(value)
win32event.PulseEvent(event)
state = property(_get_state, _set_state)
def wait(self, state, interval=0.1, channel=None):
"""Wait for the given state(s), KeyboardInterrupt or SystemExit.
Since this class uses native win32event objects, the interval
argument is ignored.
"""
if isinstance(state, (tuple, list)):
# Don't wait for an event that beat us to the punch ;)
if self.state not in state:
events = tuple([self._get_state_event(s) for s in state])
win32event.WaitForMultipleObjects(
events, 0, win32event.INFINITE)
else:
# Don't wait for an event that beat us to the punch ;)
if self.state != state:
event = self._get_state_event(state)
win32event.WaitForSingleObject(event, win32event.INFINITE)
class _ControlCodes(dict):
"""Control codes used to "signal" a service via ControlService.
User-defined control codes are in the range 128-255. We generally use
the standard Python value for the Linux signal and add 128. Example:
>>> signal.SIGUSR1
10
control_codes['graceful'] = 128 + 10
"""
def key_for(self, obj):
"""For the given value, return its corresponding key."""
for key, val in self.items():
if val is obj:
return key
raise ValueError("The given object could not be found: %r" % obj)
control_codes = _ControlCodes({'graceful': 138})
def signal_child(service, command):
if command == 'stop':
win32serviceutil.StopService(service)
elif command == 'restart':
win32serviceutil.RestartService(service)
else:
win32serviceutil.ControlService(service, control_codes[command])
class PyWebService(win32serviceutil.ServiceFramework):
"""Python Web Service."""
_svc_name_ = "Python Web Service"
_svc_display_name_ = "Python Web Service"
_svc_deps_ = None # sequence of service names on which this depends
_exe_name_ = "pywebsvc"
_exe_args_ = None # Default to no arguments
# Only exists on Windows 2000 or later, ignored on windows NT
_svc_description_ = "Python Web Service"
def SvcDoRun(self):
from cherrypy import process
process.bus.start()
process.bus.block()
def SvcStop(self):
from cherrypy import process
self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
process.bus.exit()
def SvcOther(self, control):
process.bus.publish(control_codes.key_for(control))
if __name__ == '__main__':
win32serviceutil.HandleCommandLine(PyWebService)

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@ -0,0 +1,448 @@
"""An implementation of the Web Site Process Bus.
This module is completely standalone, depending only on the stdlib.
Web Site Process Bus
--------------------
A Bus object is used to contain and manage site-wide behavior:
daemonization, HTTP server start/stop, process reload, signal handling,
drop privileges, PID file management, logging for all of these,
and many more.
In addition, a Bus object provides a place for each web framework
to register code that runs in response to site-wide events (like
process start and stop), or which controls or otherwise interacts with
the site-wide components mentioned above. For example, a framework which
uses file-based templates would add known template filenames to an
autoreload component.
Ideally, a Bus object will be flexible enough to be useful in a variety
of invocation scenarios:
1. The deployer starts a site from the command line via a
framework-neutral deployment script; applications from multiple frameworks
are mixed in a single site. Command-line arguments and configuration
files are used to define site-wide components such as the HTTP server,
WSGI component graph, autoreload behavior, signal handling, etc.
2. The deployer starts a site via some other process, such as Apache;
applications from multiple frameworks are mixed in a single site.
Autoreload and signal handling (from Python at least) are disabled.
3. The deployer starts a site via a framework-specific mechanism;
for example, when running tests, exploring tutorials, or deploying
single applications from a single framework. The framework controls
which site-wide components are enabled as it sees fit.
The Bus object in this package uses topic-based publish-subscribe
messaging to accomplish all this. A few topic channels are built in
('start', 'stop', 'exit', 'graceful', 'log', and 'main'). Frameworks and
site containers are free to define their own. If a message is sent to a
channel that has not been defined or has no listeners, there is no effect.
In general, there should only ever be a single Bus object per process.
Frameworks and site containers share a single Bus object by publishing
messages and subscribing listeners.
The Bus object works as a finite state machine which models the current
state of the process. Bus methods move it from one state to another;
those methods then publish to subscribed listeners on the channel for
the new state.::
O
|
V
STOPPING --> STOPPED --> EXITING -> X
A A |
| \___ |
| \ |
| V V
STARTED <-- STARTING
"""
import atexit
import os
import sys
import threading
import time
import traceback as _traceback
import warnings
from cherrypy._cpcompat import set
# Here I save the value of os.getcwd(), which, if I am imported early enough,
# will be the directory from which the startup script was run. This is needed
# by _do_execv(), to change back to the original directory before execv()ing a
# new process. This is a defense against the application having changed the
# current working directory (which could make sys.executable "not found" if
# sys.executable is a relative-path, and/or cause other problems).
_startup_cwd = os.getcwd()
class ChannelFailures(Exception):
"""Exception raised when errors occur in a listener during Bus.publish().
"""
delimiter = '\n'
def __init__(self, *args, **kwargs):
# Don't use 'super' here; Exceptions are old-style in Py2.4
# See https://bitbucket.org/cherrypy/cherrypy/issue/959
Exception.__init__(self, *args, **kwargs)
self._exceptions = list()
def handle_exception(self):
"""Append the current exception to self."""
self._exceptions.append(sys.exc_info()[1])
def get_instances(self):
"""Return a list of seen exception instances."""
return self._exceptions[:]
def __str__(self):
exception_strings = map(repr, self.get_instances())
return self.delimiter.join(exception_strings)
__repr__ = __str__
def __bool__(self):
return bool(self._exceptions)
__nonzero__ = __bool__
# Use a flag to indicate the state of the bus.
class _StateEnum(object):
class State(object):
name = None
def __repr__(self):
return "states.%s" % self.name
def __setattr__(self, key, value):
if isinstance(value, self.State):
value.name = key
object.__setattr__(self, key, value)
states = _StateEnum()
states.STOPPED = states.State()
states.STARTING = states.State()
states.STARTED = states.State()
states.STOPPING = states.State()
states.EXITING = states.State()
try:
import fcntl
except ImportError:
max_files = 0
else:
try:
max_files = os.sysconf('SC_OPEN_MAX')
except AttributeError:
max_files = 1024
class Bus(object):
"""Process state-machine and messenger for HTTP site deployment.
All listeners for a given channel are guaranteed to be called even
if others at the same channel fail. Each failure is logged, but
execution proceeds on to the next listener. The only way to stop all
processing from inside a listener is to raise SystemExit and stop the
whole server.
"""
states = states
state = states.STOPPED
execv = False
max_cloexec_files = max_files
def __init__(self):
self.execv = False
self.state = states.STOPPED
self.listeners = dict(
[(channel, set()) for channel
in ('start', 'stop', 'exit', 'graceful', 'log', 'main')])
self._priorities = {}
def subscribe(self, channel, callback, priority=None):
"""Add the given callback at the given channel (if not present)."""
if channel not in self.listeners:
self.listeners[channel] = set()
self.listeners[channel].add(callback)
if priority is None:
priority = getattr(callback, 'priority', 50)
self._priorities[(channel, callback)] = priority
def unsubscribe(self, channel, callback):
"""Discard the given callback (if present)."""
listeners = self.listeners.get(channel)
if listeners and callback in listeners:
listeners.discard(callback)
del self._priorities[(channel, callback)]
def publish(self, channel, *args, **kwargs):
"""Return output of all subscribers for the given channel."""
if channel not in self.listeners:
return []
exc = ChannelFailures()
output = []
items = [(self._priorities[(channel, listener)], listener)
for listener in self.listeners[channel]]
try:
items.sort(key=lambda item: item[0])
except TypeError:
# Python 2.3 had no 'key' arg, but that doesn't matter
# since it could sort dissimilar types just fine.
items.sort()
for priority, listener in items:
try:
output.append(listener(*args, **kwargs))
except KeyboardInterrupt:
raise
except SystemExit:
e = sys.exc_info()[1]
# If we have previous errors ensure the exit code is non-zero
if exc and e.code == 0:
e.code = 1
raise
except:
exc.handle_exception()
if channel == 'log':
# Assume any further messages to 'log' will fail.
pass
else:
self.log("Error in %r listener %r" % (channel, listener),
level=40, traceback=True)
if exc:
raise exc
return output
def _clean_exit(self):
"""An atexit handler which asserts the Bus is not running."""
if self.state != states.EXITING:
warnings.warn(
"The main thread is exiting, but the Bus is in the %r state; "
"shutting it down automatically now. You must either call "
"bus.block() after start(), or call bus.exit() before the "
"main thread exits." % self.state, RuntimeWarning)
self.exit()
def start(self):
"""Start all services."""
atexit.register(self._clean_exit)
self.state = states.STARTING
self.log('Bus STARTING')
try:
self.publish('start')
self.state = states.STARTED
self.log('Bus STARTED')
except (KeyboardInterrupt, SystemExit):
raise
except:
self.log("Shutting down due to error in start listener:",
level=40, traceback=True)
e_info = sys.exc_info()[1]
try:
self.exit()
except:
# Any stop/exit errors will be logged inside publish().
pass
# Re-raise the original error
raise e_info
def exit(self):
"""Stop all services and prepare to exit the process."""
exitstate = self.state
try:
self.stop()
self.state = states.EXITING
self.log('Bus EXITING')
self.publish('exit')
# This isn't strictly necessary, but it's better than seeing
# "Waiting for child threads to terminate..." and then nothing.
self.log('Bus EXITED')
except:
# This method is often called asynchronously (whether thread,
# signal handler, console handler, or atexit handler), so we
# can't just let exceptions propagate out unhandled.
# Assume it's been logged and just die.
os._exit(70) # EX_SOFTWARE
if exitstate == states.STARTING:
# exit() was called before start() finished, possibly due to
# Ctrl-C because a start listener got stuck. In this case,
# we could get stuck in a loop where Ctrl-C never exits the
# process, so we just call os.exit here.
os._exit(70) # EX_SOFTWARE
def restart(self):
"""Restart the process (may close connections).
This method does not restart the process from the calling thread;
instead, it stops the bus and asks the main thread to call execv.
"""
self.execv = True
self.exit()
def graceful(self):
"""Advise all services to reload."""
self.log('Bus graceful')
self.publish('graceful')
def block(self, interval=0.1):
"""Wait for the EXITING state, KeyboardInterrupt or SystemExit.
This function is intended to be called only by the main thread.
After waiting for the EXITING state, it also waits for all threads
to terminate, and then calls os.execv if self.execv is True. This
design allows another thread to call bus.restart, yet have the main
thread perform the actual execv call (required on some platforms).
"""
try:
self.wait(states.EXITING, interval=interval, channel='main')
except (KeyboardInterrupt, IOError):
# The time.sleep call might raise
# "IOError: [Errno 4] Interrupted function call" on KBInt.
self.log('Keyboard Interrupt: shutting down bus')
self.exit()
except SystemExit:
self.log('SystemExit raised: shutting down bus')
self.exit()
raise
# Waiting for ALL child threads to finish is necessary on OS X.
# See https://bitbucket.org/cherrypy/cherrypy/issue/581.
# It's also good to let them all shut down before allowing
# the main thread to call atexit handlers.
# See https://bitbucket.org/cherrypy/cherrypy/issue/751.
self.log("Waiting for child threads to terminate...")
for t in threading.enumerate():
# Validate the we're not trying to join the MainThread
# that will cause a deadlock and the case exist when
# implemented as a windows service and in any other case
# that another thread executes cherrypy.engine.exit()
if (
t != threading.currentThread() and
t.isAlive() and
not isinstance(t, threading._MainThread)
):
# Note that any dummy (external) threads are always daemonic.
if hasattr(threading.Thread, "daemon"):
# Python 2.6+
d = t.daemon
else:
d = t.isDaemon()
if not d:
self.log("Waiting for thread %s." % t.getName())
t.join()
if self.execv:
self._do_execv()
def wait(self, state, interval=0.1, channel=None):
"""Poll for the given state(s) at intervals; publish to channel."""
if isinstance(state, (tuple, list)):
states = state
else:
states = [state]
def _wait():
while self.state not in states:
time.sleep(interval)
self.publish(channel)
# From http://psyco.sourceforge.net/psycoguide/bugs.html:
# "The compiled machine code does not include the regular polling
# done by Python, meaning that a KeyboardInterrupt will not be
# detected before execution comes back to the regular Python
# interpreter. Your program cannot be interrupted if caught
# into an infinite Psyco-compiled loop."
try:
sys.modules['psyco'].cannotcompile(_wait)
except (KeyError, AttributeError):
pass
_wait()
def _do_execv(self):
"""Re-execute the current process.
This must be called from the main thread, because certain platforms
(OS X) don't allow execv to be called in a child thread very well.
"""
args = sys.argv[:]
self.log('Re-spawning %s' % ' '.join(args))
if sys.platform[:4] == 'java':
from _systemrestart import SystemRestart
raise SystemRestart
else:
args.insert(0, sys.executable)
if sys.platform == 'win32':
args = ['"%s"' % arg for arg in args]
os.chdir(_startup_cwd)
if self.max_cloexec_files:
self._set_cloexec()
os.execv(sys.executable, args)
def _set_cloexec(self):
"""Set the CLOEXEC flag on all open files (except stdin/out/err).
If self.max_cloexec_files is an integer (the default), then on
platforms which support it, it represents the max open files setting
for the operating system. This function will be called just before
the process is restarted via os.execv() to prevent open files
from persisting into the new process.
Set self.max_cloexec_files to 0 to disable this behavior.
"""
for fd in range(3, self.max_cloexec_files): # skip stdin/out/err
try:
flags = fcntl.fcntl(fd, fcntl.F_GETFD)
except IOError:
continue
fcntl.fcntl(fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC)
def stop(self):
"""Stop all services."""
self.state = states.STOPPING
self.log('Bus STOPPING')
self.publish('stop')
self.state = states.STOPPED
self.log('Bus STOPPED')
def start_with_callback(self, func, args=None, kwargs=None):
"""Start 'func' in a new thread T, then start self (and return T)."""
if args is None:
args = ()
if kwargs is None:
kwargs = {}
args = (func,) + args
def _callback(func, *a, **kw):
self.wait(states.STARTED)
func(*a, **kw)
t = threading.Thread(target=_callback, args=args, kwargs=kwargs)
t.setName('Bus Callback ' + t.getName())
t.start()
self.start()
return t
def log(self, msg="", level=20, traceback=False):
"""Log the given message. Append the last traceback if requested."""
if traceback:
msg += "\n" + "".join(_traceback.format_exception(*sys.exc_info()))
self.publish('log', msg, level)
bus = Bus()