closes db connection on worker and monitor spawn

This should prevent some problems with Postgresql where the workers would use stale db connections  and cause errors.

django_q/cluster.py

@@ -31,6 +31,7 @@ except ImportError:
 # Django
 from django.utils import timezone
 from django.utils.translation import ugettext_lazy as _
+from django import db
 
 # Local
 import signing
@@ -328,6 +329,7 @@ def monitor(result_queue):
     """
     name = current_process().name
     logger.info(_("{} monitoring at {}").format(name, current_process().pid))
+    db.close_old_connections()
     for task in iter(result_queue.get, 'STOP'):
         save_task(task)
         if task['success']:
@@ -346,6 +348,7 @@ def worker(task_queue, result_queue, timer, timeout=Conf.TIMEOUT):
     """
     name = current_process().name
     logger.info(_('{} ready for work at {}').format(name, current_process().pid))
+    db.close_old_connections()
     task_count = 0
     # Start reading the task queue
     for pack in iter(task_queue.get, 'STOP'):
@@ -399,9 +402,9 @@ def save_task(task):
     if not task.get('save', Conf.SAVE_LIMIT > 0) and task['success']:
         return
     # SAVE LIMIT > 0: Prune database, SAVE_LIMIT 0: No pruning
+    try:
         if task['success'] and 0 < Conf.SAVE_LIMIT < Success.objects.count():
             Success.objects.last().delete()
-    try:
         Task.objects.create(id=task['id'],
                             name=task['name'],
                             func=task['func'],
@@ -421,6 +424,7 @@ def scheduler(list_key=Conf.Q_LIST):
     """
     Creates a task from a schedule at the scheduled time and schedules next run
     """
+    try:
         for s in Schedule.objects.exclude(repeats=0).filter(next_run__lt=timezone.now()):
             args = ()
             kwargs = {}
@@ -477,6 +481,8 @@ def scheduler(list_key=Conf.Q_LIST):
                 s.repeats = 0
             # save the schedule
             s.save()
+    except Exception as e:
+        logger.error(e)
 
 
 def set_cpu_affinity(n, process_ids, actual=not Conf.TESTING):