openstack/deb-python-taskflow
Code Issues Proposed changes

Add the ability to soft_reset a workflow.

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In cases where it is not desired to reset the whole state
of the workflow, but only to soft_reset it so that it can
be easily resumed from a interrupted state (for example).
This change allows for that to happen, which involves also
keeping track of the last task that ran so when resumed via
soft_reset that task can be the one started off from (instead
of starting from the start of all tasks).

Change-Id: I034bd6af6445e3da52356328605368319c4ff6f9
This commit is contained in:
Joshua Harlow
2013-06-05 12:06:00 -07:00
parent 16a5e1c27f
commit 14a3d594c5
1 changed files with 26 additions and 1 deletions
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27
taskflow/patterns/ordered_flow.py
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@@ -92,6 +92,9 @@ class Flow(object):
self._state = states.PENDING self._state = states.PENDING
# Tasks results are stored here... # Tasks results are stored here...
self.results = [] self.results = []
# The last task index in the order we left off at before being
# interrupted (or failing).
self._left_off_at = 0
@property @property
def state(self): def state(self):
@@ -129,6 +132,8 @@ class Flow(object):
self._change_state(context, states.STARTED) self._change_state(context, states.STARTED)
try: try:
task_order = self.order() task_order = self.order()
if self._left_off_at > 0:
task_order = task_order[self._left_off_at:]
except Exception: except Exception:
with excutils.save_and_reraise_exception(): with excutils.save_and_reraise_exception():
try: try:
@@ -160,6 +165,8 @@ class Flow(object):
" object: %s", result) " object: %s", result)
result = exc.InvalidStateException() result = exc.InvalidStateException()
raise result raise result
# Alter the index we have ran at.
self._left_off_at += 1
# Keep a pristine copy of the result # Keep a pristine copy of the result
# so that if said result is altered by other further # so that if said result is altered by other further
# states the one here will not be. This ensures that # states the one here will not be. This ensures that
@@ -216,15 +223,33 @@ class Flow(object):
self._change_state(context, states.SUCCESS) self._change_state(context, states.SUCCESS)
def reset(self): 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._state = states.PENDING
self.results = [] self.results = []
self.task_listeners = [] self.task_listeners = []
self.listeners = [] self.listeners = []
self.result_fetcher = None self.result_fetcher = None
self._accumulator.reset() 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): 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) self._change_state(None, states.INTERRUPTED)
def _change_state(self, context, new_state): def _change_state(self, context, new_state):