Files
deb-python-taskflow/taskflow/engines/action_engine/graph_action.py
Joshua Harlow 9560693068 Use constants for the execution event strings
Since these will be used in the future, add a
comment saying this, as well as switch to using
executor level constants instead of local strings
for these events.

Change-Id: I0bd6e1ca09da0dbae0d0c2787ceb9ce1a41cb7de
2014-01-08 10:12:25 -08:00

105 lines
3.7 KiB
Python

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from taskflow import states as st
from taskflow.utils import misc
_WAITING_TIMEOUT = 60 # in seconds
class FutureGraphAction(object):
"""Graph action build around futures returned by task action.
This graph action schedules all task it can for execution and than
waits on returned futures. If task executor is able to execute tasks
in parallel, this enables parallel flow run and reversion.
"""
def __init__(self, analyzer, storage, task_action):
self._analyzer = analyzer
self._storage = storage
self._task_action = task_action
def is_running(self):
return self._storage.get_flow_state() == st.RUNNING
def is_reverting(self):
return self._storage.get_flow_state() == st.REVERTING
def execute(self):
was_suspended = self._run(
self.is_running,
self._task_action.schedule_execution,
self._task_action.complete_execution,
self._analyzer.browse_nodes_for_execute)
return st.SUSPENDED if was_suspended else st.SUCCESS
def revert(self):
was_suspended = self._run(
self.is_reverting,
self._task_action.schedule_reversion,
self._task_action.complete_reversion,
self._analyzer.browse_nodes_for_revert)
return st.SUSPENDED if was_suspended else st.REVERTED
def _run(self, running, schedule_node, complete_node, get_next_nodes):
def schedule(nodes, not_done):
for node in nodes:
future = schedule_node(node)
if future is not None:
not_done.append(future)
else:
schedule(get_next_nodes(node), not_done)
failures = []
not_done = []
schedule(get_next_nodes(), not_done)
was_suspended = False
while not_done:
# NOTE(imelnikov): if timeout occurs before any of futures
# completes, done list will be empty and we'll just go
# for next iteration
done, not_done = self._task_action.wait_for_any(
not_done, _WAITING_TIMEOUT)
not_done = list(not_done)
next_nodes = []
for future in done:
# NOTE(harlowja): event will be used in the future for smart
# reversion (ignoring it for now).
node, _event, result = future.result()
complete_node(node, result)
if isinstance(result, misc.Failure):
failures.append(result)
else:
next_nodes.extend(get_next_nodes(node))
if next_nodes:
if running() and not failures:
schedule(next_nodes, not_done)
else:
# NOTE(imelnikov): engine stopped while there were
# still some tasks to do, so we either failed
# or were suspended
was_suspended = True
misc.Failure.reraise_if_any(failures)
return was_suspended