added timezone support

.project

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>django-background-task</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.python.pydev.PyDevBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.python.pydev.pythonNature</nature>
+	</natures>
+</projectDescription>

.pydevproject

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<?eclipse-pydev version="1.0"?><pydev_project>
+<pydev_property name="org.python.pydev.PYTHON_PROJECT_INTERPRETER">Default</pydev_property>
+<pydev_property name="org.python.pydev.PYTHON_PROJECT_VERSION">python 2.7</pydev_property>
+</pydev_project>

background_task/models.py

@@ -3,6 +3,7 @@
 from django.conf import settings
 
 from django.utils import simplejson
+from django.utils.timezone import utc
 from datetime import datetime, timedelta
 from hashlib import sha1
 import traceback
@@ -15,7 +16,7 @@
 class TaskManager(models.Manager):
 
     def find_available(self):
-        now = datetime.now()
+        now = datetime.utcnow().replace(tzinfo=utc)
         qs = self.unlocked(now)
         ready = qs.filter(run_at__lte=now, failed_at=None)
         return ready.order_by('-priority', 'run_at')
@@ -32,7 +33,7 @@ def new_task(self, task_name, args=None, kwargs=None,
         args = args or ()
         kwargs = kwargs or {}
         if run_at is None:
-            run_at = datetime.now()
+            run_at = datetime.utcnow().replace(tzinfo=utc)
 
         task_params = simplejson.dumps((args, kwargs))
         task_hash = sha1(task_name + task_params).hexdigest()
@@ -78,29 +79,29 @@ def params(self):
         return args, kwargs
 
     def lock(self, locked_by):
-        now = datetime.now()
+        now = datetime.utcnow().replace(tzinfo=utc)
         unlocked = Task.objects.unlocked(now).filter(pk=self.pk)
         updated = unlocked.update(locked_by=locked_by, locked_at=now)
         if updated:
             return Task.objects.get(pk=self.pk)
         return None
-    
+
     def _extract_error(self, type, err, tb):
         file = StringIO()
         traceback.print_exception(type, err, tb, None, file)
         return file.getvalue()
-    
+
     def reschedule(self, type, err, traceback):
         self.last_error = self._extract_error(type, err, traceback)
         max_attempts = getattr(settings, 'MAX_ATTEMPTS', 25)
 
         if self.attempts >= max_attempts:
-            self.failed_at = datetime.now()
+            self.failed_at = datetime.utcnow().replace(tzinfo=utc)
             logging.warn('Marking task %s as failed', self)
         else:
             self.attempts += 1
             backoff = timedelta(seconds=(self.attempts ** 4) + 5)
-            self.run_at = datetime.now() + backoff
+            self.run_at = datetime.utcnow().replace(tzinfo=utc) + backoff
             logging.warn('Rescheduling task %s for %s later at %s', self,
                 backoff, self.run_at)
 
@@ -109,7 +110,7 @@ def reschedule(self, type, err, traceback):
         self.locked_at = None
 
         self.save()
-    
+
     def save(self, *arg, **kw):
         # force NULL rather than empty string
         self.locked_by = self.locked_by or None

background_task/tasks.py

@@ -6,6 +6,7 @@
 from datetime import datetime, timedelta
 from django.db import transaction
 from django.utils.importlib import import_module
+from django.utils.timezone import utc
 
 
 class Tasks(object):
@@ -19,22 +20,22 @@ def background(self, name=None, schedule=None):
         something that gets run asynchronously in
         the background, at a later time
         '''
-        
+
         # see if used as simple decorator
         # where first arg is the function to be decorated
         fn = None
         if name and callable(name):
             fn = name
             name = None
-        
+
         def _decorator(fn):
             _name = name
             if not _name:
                 _name = '%s.%s' % (fn.__module__, fn.__name__)
             proxy = TaskProxy(_name, fn, schedule, self._runner)
             self._tasks[_name] = proxy
             return proxy
-        
+
         if fn:
             return _decorator(fn)
 
@@ -87,7 +88,7 @@ def merge(self, schedule):
 
     @property
     def run_at(self):
-        run_at = self._run_at or datetime.now()
+        run_at = self._run_at or datetime.utcnow().replace(tzinfo=utc)
         if isinstance(run_at, int):
             run_at = datetime.now() + timedelta(seconds=run_at)
         if isinstance(run_at, timedelta):
@@ -130,7 +131,8 @@ def schedule(self, task_name, args, kwargs, run_at=None,
 
         if action != TaskSchedule.SCHEDULE:
             task_hash = task.task_hash
-            unlocked = Task.objects.unlocked(datetime.now())
+            now = datetime.utcnow().replace(tzinfo=utc)
+            unlocked = Task.objects.unlocked(now)
             existing = unlocked.filter(task_hash=task_hash)
             if action == TaskSchedule.RESCHEDULE_EXISTING:
                 updated = existing.update(run_at=run_at, priority=priority)