Merge "Add the ability to soft_reset a workflow."

taskflow/patterns/ordered_flow.py

@@ -92,6 +92,9 @@ class Flow(object):
         self._state = states.PENDING
         # Tasks results are stored here...
         self.results = []
+        # The last task index in the order we left off at before being
+        # interrupted (or failing).
+        self._left_off_at = 0
 
     @property
     def state(self):
@@ -129,6 +132,8 @@ class Flow(object):
         self._change_state(context, states.STARTED)
         try:
             task_order = self.order()
+            if self._left_off_at > 0:
+                task_order = task_order[self._left_off_at:]
         except Exception:
             with excutils.save_and_reraise_exception():
                 try:
@@ -160,6 +165,8 @@ class Flow(object):
                                      " object: %s", result)
                             result = exc.InvalidStateException()
                         raise result
+                # Alter the index we have ran at.
+                self._left_off_at += 1
                 # Keep a pristine copy of the result
                 # so that if said result is altered by other further
                 # states the one here will not be. This ensures that
@@ -216,15 +223,33 @@ class Flow(object):
             self._change_state(context, states.SUCCESS)
 
     def reset(self):
-        # Reset all internal state (except our parent workflows).
+        # Reset (hard) alters the local state and does clear out other member
+        # variables state.
+        if self.state not in (states.INTERRUPTED, states.SUCCESS,
+                              states.FAILURE, states.PENDING):
+            raise exc.InvalidStateException(("Can not reset when"
+                                             " in state %s") % (self.state))
         self._state = states.PENDING
         self.results = []
         self.task_listeners = []
         self.listeners = []
         self.result_fetcher = None
         self._accumulator.reset()
+        self._left_off_at = 0
+
+    def soft_reset(self):
+        # Soft reset only alters the local state and does not clear out any
+        # other member variables state.
+        if self.state not in (states.INTERRUPTED, states.SUCCESS,
+                              states.PENDING):
+            raise exc.InvalidStateException(("Can not soft_reset when"
+                                             " in state %s") % (self.state))
+        self._state = states.PENDING
 
     def interrupt(self):
+        if self.state in (states.FAILURE, states.SUCCESS, states.PENDING):
+            raise exc.InvalidStateException(("Can not interrupt when"
+                                             " in state %s") % (self.state))
         self._change_state(None, states.INTERRUPTED)
 
     def _change_state(self, context, new_state):