Merge pull request #463 from conslo/skip-queue

Skip queue

rq/queue.py

@@ -149,7 +149,7 @@ class Queue(object):
 
     def compact(self):
         """Removes all "dead" jobs from the queue by cycling through it, while
-        guarantueeing FIFO semantics.
+        guaranteeing FIFO semantics.
         """
         COMPACT_QUEUE = 'rq:queue:_compact:{0}'.format(uuid.uuid4())
 
@@ -161,14 +161,18 @@ class Queue(object):
             if self.job_class.exists(job_id, self.connection):
                 self.connection.rpush(self.key, job_id)
 
-    def push_job_id(self, job_id, pipeline=None):
-        """Pushes a job ID on the corresponding Redis queue."""
+    def push_job_id(self, job_id, pipeline=None, at_front=False):
+        """Pushes a job ID on the corresponding Redis queue.
+        'at_front' allows you to push the job onto the front instead of the back of the queue"""
         connection = pipeline if pipeline is not None else self.connection
-        connection.rpush(self.key, job_id)
+        if at_front:
+            connection.lpush(self.key, job_id)
+        else:
+            connection.rpush(self.key, job_id)
 
     def enqueue_call(self, func, args=None, kwargs=None, timeout=None,
                      result_ttl=None, ttl=None, description=None,
-                     depends_on=None, job_id=None):
+                     depends_on=None, job_id=None, at_front=False):
         """Creates a job to represent the delayed function call and enqueues
         it.
 
@@ -204,7 +208,7 @@ class Queue(object):
                     except WatchError:
                         continue
 
-        return self.enqueue_job(job)
+        return self.enqueue_job(job, at_front=at_front)
 
     def enqueue(self, f, *args, **kwargs):
         """Creates a job to represent the delayed function call and enqueues
@@ -232,6 +236,7 @@ class Queue(object):
         ttl = kwargs.pop('ttl', None)
         depends_on = kwargs.pop('depends_on', None)
         job_id = kwargs.pop('job_id', None)
+        at_front = kwargs.pop('at_front', False)
 
         if 'args' in kwargs or 'kwargs' in kwargs:
             assert args == (), 'Extra positional arguments cannot be used when using explicit args and kwargs.'  # noqa
@@ -241,9 +246,9 @@ class Queue(object):
         return self.enqueue_call(func=f, args=args, kwargs=kwargs,
                                  timeout=timeout, result_ttl=result_ttl, ttl=ttl,
                                  description=description, depends_on=depends_on,
-                                 job_id=job_id)
+                                 job_id=job_id, at_front=at_front)
 
-    def enqueue_job(self, job, set_meta_data=True):
+    def enqueue_job(self, job, set_meta_data=True, at_front=False):
         """Enqueues a job for delayed execution.
 
         If the `set_meta_data` argument is `True` (default), it will update
@@ -263,7 +268,7 @@ class Queue(object):
         job.save()
 
         if self._async:
-            self.push_job_id(job.id)
+            self.push_job_id(job.id, at_front=at_front)
         else:
             job.perform()
             job.save()

tests/test_queue.py

@@ -459,3 +459,13 @@ class TestFailedQueue(RQTestCase):
         """Ensure custom job class assignment works as expected."""
         q = Queue(job_class=CustomJob)
         self.assertEqual(q.job_class, CustomJob)
+
+    def test_skip_queue(self):
+        """Ensure the skip_queue option functions"""
+        q = Queue('foo')
+        job1 = q.enqueue(say_hello)
+        job2 = q.enqueue(say_hello)
+        assert q.dequeue() == job1
+        skip_job = q.enqueue(say_hello, at_front=True)
+        assert q.dequeue() == skip_job
+        assert q.dequeue() == job2