Initial Commit

lib/logutils/redis.py

@@ -0,0 +1,75 @@
+#
+# Copyright (C) 2011-2013 Vinay Sajip. See LICENSE.txt for details.
+#
+"""
+This module contains classes which help you work with Redis queues.
+"""
+
+from logutils.queue import QueueHandler, QueueListener
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+
+class RedisQueueHandler(QueueHandler):
+    """
+    A QueueHandler implementation which pushes pickled
+    records to a Redis queue using a specified key.
+    
+    :param key: The key to use for the queue. Defaults to
+                "python.logging".
+    :param redis: If specified, this instance is used to
+                  communicate with a Redis instance.
+    :param limit: If specified, the queue is restricted to
+                  have only this many elements.
+    """
+    def __init__(self, key='python.logging', redis=None, limit=0):
+        if redis is None:
+            from redis import Redis
+            redis = Redis()
+        self.key = key
+        assert limit >= 0
+        self.limit = limit
+        QueueHandler.__init__(self, redis)
+        
+    def enqueue(self, record):
+        s = pickle.dumps(vars(record))
+        self.queue.rpush(self.key, s)
+        if self.limit:
+            self.queue.ltrim(self.key, -self.limit, -1)
+
+class RedisQueueListener(QueueListener):
+    """
+    A QueueListener implementation which fetches pickled
+    records from a Redis queue using a specified key.
+    
+    :param key: The key to use for the queue. Defaults to
+                "python.logging".
+    :param redis: If specified, this instance is used to
+                  communicate with a Redis instance.
+    """
+    def __init__(self, *handlers, **kwargs):
+        redis = kwargs.get('redis')
+        if redis is None:
+            from redis import Redis
+            redis = Redis()
+        self.key = kwargs.get('key', 'python.logging')
+        QueueListener.__init__(self, redis, *handlers)
+
+    def dequeue(self, block):
+        """
+        Dequeue and return a record.
+        """
+        if block:
+            s = self.queue.blpop(self.key)[1]
+        else:
+            s = self.queue.lpop(self.key)        
+        if not s:
+            record = None
+        else:
+            record = pickle.loads(s)
+        return record
+
+    def enqueue_sentinel(self):
+        self.queue.rpush(self.key, '')
+