208 lines
7.3 KiB
Python
208 lines
7.3 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.
|
|
|
|
import multiprocessing
|
|
import threading
|
|
|
|
from concurrent import futures
|
|
|
|
from taskflow.engines.action_engine import graph_action
|
|
from taskflow.engines.action_engine import task_action
|
|
|
|
from taskflow import decorators
|
|
from taskflow import exceptions as exc
|
|
from taskflow import states
|
|
from taskflow import storage as t_storage
|
|
|
|
from taskflow.utils import flow_utils
|
|
from taskflow.utils import misc
|
|
from taskflow.utils import persistence_utils as p_utils
|
|
|
|
|
|
class ActionEngine(object):
|
|
"""Generic action-based engine.
|
|
|
|
Converts the flow to recursive structure of actions.
|
|
"""
|
|
_graph_action = None
|
|
|
|
def __init__(self, flow, storage):
|
|
self._failures = []
|
|
self._root = None
|
|
self._flow = flow
|
|
self._lock = threading.RLock()
|
|
self._state_lock = threading.RLock()
|
|
self.notifier = misc.TransitionNotifier()
|
|
self.task_notifier = misc.TransitionNotifier()
|
|
self.storage = storage
|
|
|
|
def _revert(self, current_failure):
|
|
self._change_state(states.REVERTING)
|
|
state = self._root.revert(self)
|
|
self._change_state(state)
|
|
if state == states.SUSPENDED:
|
|
return
|
|
self._change_state(states.FAILURE)
|
|
if self._failures:
|
|
if len(self._failures) == 1:
|
|
self._failures[0].reraise()
|
|
else:
|
|
exc_infos = [f.exc_info for f in self._failures]
|
|
raise exc.LinkedException.link(exc_infos)
|
|
else:
|
|
current_failure.reraise()
|
|
|
|
def _reset(self):
|
|
self._failures = []
|
|
|
|
def suspend(self):
|
|
self._change_state(states.SUSPENDING)
|
|
|
|
def get_graph(self):
|
|
self.compile()
|
|
return self._root.graph
|
|
|
|
@decorators.locked
|
|
def run(self):
|
|
if self.storage.get_flow_state() != states.SUSPENDED:
|
|
self.compile()
|
|
self._reset()
|
|
|
|
external_provides = set(self.storage.fetch_all().keys())
|
|
missing = self._flow.requires - external_provides
|
|
if missing:
|
|
raise exc.MissingDependencies(self._flow, sorted(missing))
|
|
self._run()
|
|
elif self._failures:
|
|
self._revert(self._failures[-1])
|
|
else:
|
|
self._run()
|
|
|
|
def _run(self):
|
|
self._change_state(states.RUNNING)
|
|
try:
|
|
state = self._root.execute(self)
|
|
except Exception:
|
|
self._revert(misc.Failure())
|
|
else:
|
|
self._change_state(state)
|
|
|
|
@decorators.locked(lock='_state_lock')
|
|
def _change_state(self, state):
|
|
if (state == states.SUSPENDING and not (self.is_running or
|
|
self.is_reverting)):
|
|
return
|
|
self.storage.set_flow_state(state)
|
|
details = dict(engine=self)
|
|
self.notifier.notify(state, details)
|
|
|
|
def on_task_state_change(self, task_action, state, result=None):
|
|
if isinstance(result, misc.Failure):
|
|
self._failures.append(result)
|
|
details = dict(engine=self,
|
|
task_name=task_action.name,
|
|
task_uuid=task_action.uuid,
|
|
result=result)
|
|
self.task_notifier.notify(state, details)
|
|
|
|
def _translate_flow_to_action(self):
|
|
assert self._graph_action is not None, ('Graph action class must be'
|
|
' specified')
|
|
task_graph = flow_utils.flatten(self._flow)
|
|
ga = self._graph_action(task_graph)
|
|
for n in task_graph.nodes_iter():
|
|
ga.add(n, task_action.TaskAction(n, self))
|
|
return ga
|
|
|
|
def compile(self):
|
|
if self._root is None:
|
|
self._root = self._translate_flow_to_action()
|
|
|
|
@property
|
|
def is_running(self):
|
|
return self.storage.get_flow_state() == states.RUNNING
|
|
|
|
@property
|
|
def is_reverting(self):
|
|
return self.storage.get_flow_state() == states.REVERTING
|
|
|
|
|
|
class SingleThreadedActionEngine(ActionEngine):
|
|
# This one attempts to run in a serial manner.
|
|
_graph_action = graph_action.SequentialGraphAction
|
|
|
|
def __init__(self, flow, flow_detail=None, book=None, backend=None):
|
|
if flow_detail is None:
|
|
flow_detail = p_utils.create_flow_detail(flow,
|
|
book=book,
|
|
backend=backend)
|
|
ActionEngine.__init__(self, flow,
|
|
storage=t_storage.Storage(flow_detail, backend))
|
|
|
|
|
|
class MultiThreadedActionEngine(ActionEngine):
|
|
# This one attempts to run in a parallel manner.
|
|
_graph_action = graph_action.ParallelGraphAction
|
|
|
|
def __init__(self, flow, flow_detail=None, book=None, backend=None,
|
|
executor=None):
|
|
if flow_detail is None:
|
|
flow_detail = p_utils.create_flow_detail(flow,
|
|
book=book,
|
|
backend=backend)
|
|
ActionEngine.__init__(self, flow,
|
|
storage=t_storage.ThreadSafeStorage(flow_detail,
|
|
backend))
|
|
if executor is not None:
|
|
self._executor = executor
|
|
self._owns_executor = False
|
|
self._thread_count = -1
|
|
else:
|
|
self._executor = None
|
|
self._owns_executor = True
|
|
# TODO(harlowja): allow this to be configurable??
|
|
try:
|
|
self._thread_count = multiprocessing.cpu_count() + 1
|
|
except NotImplementedError:
|
|
# NOTE(harlowja): apparently may raise so in this case we will
|
|
# just setup two threads since its hard to know what else we
|
|
# should do in this situation.
|
|
self._thread_count = 2
|
|
|
|
@decorators.locked
|
|
def run(self):
|
|
if self._owns_executor:
|
|
if self._executor is not None:
|
|
# The previous shutdown failed, something is very wrong.
|
|
raise exc.InvalidStateException("The previous shutdown() of"
|
|
" the executor powering this"
|
|
" engine failed. Something is"
|
|
" very very wrong.")
|
|
self._executor = futures.ThreadPoolExecutor(self._thread_count)
|
|
try:
|
|
ActionEngine.run(self)
|
|
finally:
|
|
# Don't forget to shutdown the executor!!
|
|
if self._owns_executor and self._executor is not None:
|
|
self._executor.shutdown(wait=True)
|
|
self._executor = None
|
|
|
|
@property
|
|
def executor(self):
|
|
return self._executor
|