Added asynchronous notification sending.

git-svn-id: http://django-notification.googlecode.com/svn/trunk@97 590c3fc9-4838-0410-bb95-17a0c9b37ca9

notification/engine.py

@@ -0,0 +1,58 @@
+
+import time
+import logging
+
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+
+from django.conf import settings
+from django.contrib.auth.models import User
+
+from lockfile import FileLock, AlreadyLocked, LockTimeout
+
+from notification.models import NoticeQueue
+from notification import models as notification
+
+# lock timeout value. how long to wait for the lock to become available.
+# default behavior is to never wait for the lock to be available.
+LOCK_WAIT_TIMEOUT = getattr(settings, "NOTIFICATION_LOCK_WAIT_TIMEOUT", -1)
+
+def send_all():
+    lock = FileLock("send_notices")
+
+    logging.debug("acquiring lock...")
+    try:
+        lock.acquire(LOCK_WAIT_TIMEOUT)
+    except AlreadyLocked:
+        logging.debug("lock already in place. quitting.")
+        return
+    except LockTimeout:
+        logging.debug("waiting for the lock timed out. quitting.")
+        return
+    logging.debug("acquired.")
+
+    batches, sent = 0, 0
+    start_time = time.time()
+
+    try:
+        for queued_batch in NoticeQueue.objects.all():
+            notices = pickle.loads(str(queued_batch.pickled_data))
+            for user, label, extra_context, on_site in notices:
+                user = User.objects.get(pk=user)
+                logging.info("emitting notice to %s" % user)
+                # call this once per user to be atomic and allow for logging to
+                # accurately show how long each takes.
+                notification.send([user], label, extra_context, on_site)
+                sent += 1
+            queued_batch.delete()
+            batches += 1
+    finally:
+        logging.debug("releasing lock...")
+        lock.release()
+        logging.debug("released.")
+
+    logging.info("")
+    logging.info("%s batches, %s sent" % (batches, sent,))
+    logging.info("done in %.2f seconds" % (time.time() - start_time))