Add option (default=True) for rescheduling callbacks along w/task.

Also reschedule the original priority and support overriding priority
when rescheduling.

huey/api.py

@@ -996,21 +996,31 @@ def revoke(self, revoke_once=True):
     def restore(self):
         return self.huey.restore(self.task)
 
-    def reschedule(self, eta=None, delay=None, expires=None):
+    def reschedule(self, eta=None, delay=None, expires=None, priority=None,
+                   preserve_pipeline=True):
         # Rescheduling works by revoking the currently-scheduled task (nothing
         # is done to check if the task has already run, however). Then the
         # original task's data is used to enqueue a new task with a new task ID
         # and execution_time.
         self.revoke()
         if eta is not None or delay is not None:
             eta = normalize_time(eta, delay, self.huey.utc)
+        if preserve_pipeline:
+            on_complete = self.task.on_complete
+            on_error = self.task.on_error
+        else:
+            on_complete = on_error = None
+
         task = type(self.task)(
             self.task.args,
             self.task.kwargs,
             eta=eta,
             retries=self.task.retries,
             retry_delay=self.task.retry_delay,
-            expires=expires if expires is not None else self.task.expires)
+            priority=priority if priority is not None else self.task.priority,
+            expires=expires if expires is not None else self.task.expires,
+            on_complete=on_complete,
+            on_error=on_error)
         return self.huey.enqueue(task)
 
     def reset(self):

huey/tests/test_api.py

@@ -131,9 +131,10 @@ def test_schedule_s(self):
         def add(a, b):
             return a + b
 
-        task = add.s((1, 2), delay=10)
-        task = task.then(add, (3,), delay=20)
-        self.huey.execute(task)
+        task = add.s(1, 2, delay=10)
+        task = task.then(add, 3, delay=20)
+        r1, r2 = self.huey.enqueue(task)
+        self.execute_next()
 
         sched = self.huey.scheduled()
         self.assertEqual(len(sched), 1)
@@ -148,6 +149,16 @@ def add(a, b):
         self.assertFalse(self.huey.ready_to_run(oc, t10))
         self.assertTrue(self.huey.ready_to_run(oc, t20))
 
+        r = r1.reschedule()
+        self.assertEqual(len(self.huey), 1)
+        self.assertEqual(self.execute_next(), 3)
+
+        self.assertEqual(len(self.huey), 1)
+        task = self.huey.dequeue()
+        self.assertFalse(self.huey.ready_to_run(task))
+        self.assertTrue(self.huey.ready_to_run(task, t20))
+        self.assertEqual(self.huey.execute(task, t20), 6)
+
     def test_revoke_task(self):
         state = {}
         @self.huey.task()
@@ -568,6 +579,29 @@ def task_s(task=None):
         self.assertEqual(self.huey.execute(task), True)
         self.assertEqual(state, [res3.id])
 
+    def test_reschedule_priority(self):
+        state = []
+
+        @self.huey.task(context=True)
+        def task_s(task=None):
+            state.append(task.id)
+            return True
+
+        res = task_s(priority=10)
+        res2 = res.reschedule(priority=99)
+        self.assertEqual(len(self.huey), 2)
+
+        task = self.huey.dequeue()
+        self.assertEqual(task.priority, 99)
+        self.assertTrue(self.huey.execute(task))
+
+        task = self.huey.dequeue()
+        self.assertEqual(task.priority, 10)
+        self.assertTrue(res.is_revoked())
+        self.assertTrue(self.huey.execute(task) is None)
+
+        self.assertEqual(state, [res2.id])
+
     def test_task_error(self):
         @self.huey.task()
         def task_e(n):