d433a5323f
To avoid having one set of options coming from `engine_conf` and another set of options coming from `kwargs` and another set coming from `engine_conf` if it is a URI just start to shift toward `engine_conf` being deprecated and `engine` being a string type only (or a URI with additional query parameters) and having any additional **kwargs that are provided just get merged into the final engine options. This adds a new helper function that handles all these various options and adds in a keyword argument `engine` that will be shifted to in a future version (in that future version we can also then remove the `engine_conf` and just stick to a smaller set of option mechanisms). It also adjusts all examples to use this new and more easier to understand format and adjusts tests, conductor interface to use this new more easily understandable style of getting an engine. Change-Id: Ic7617057338e0c63775cf38a24643cff6e454950
236 lines
9.3 KiB
Python
236 lines
9.3 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
# 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 contextlib
|
|
import threading
|
|
|
|
from oslo.utils import excutils
|
|
|
|
from taskflow.engines.action_engine import compiler
|
|
from taskflow.engines.action_engine import executor
|
|
from taskflow.engines.action_engine import runtime
|
|
from taskflow.engines import base
|
|
from taskflow import exceptions as exc
|
|
from taskflow import states
|
|
from taskflow import storage as atom_storage
|
|
from taskflow.utils import lock_utils
|
|
from taskflow.utils import misc
|
|
from taskflow.utils import reflection
|
|
|
|
|
|
@contextlib.contextmanager
|
|
def _start_stop(executor):
|
|
# A teenie helper context manager to safely start/stop a executor...
|
|
executor.start()
|
|
try:
|
|
yield executor
|
|
finally:
|
|
executor.stop()
|
|
|
|
|
|
class ActionEngine(base.EngineBase):
|
|
"""Generic action-based engine.
|
|
|
|
This engine compiles the flow (and any subflows) into a compilation unit
|
|
which contains the full runtime definition to be executed and then uses
|
|
this compilation unit in combination with the executor, runtime, runner
|
|
and storage classes to attempt to run your flow (and any subflows &
|
|
contained atoms) to completion.
|
|
|
|
NOTE(harlowja): during this process it is permissible and valid to have a
|
|
task or multiple tasks in the execution graph fail (at the same time even),
|
|
which will cause the process of reversion or retrying to commence. See the
|
|
valid states in the states module to learn more about what other states
|
|
the tasks and flow being ran can go through.
|
|
"""
|
|
_compiler_factory = compiler.PatternCompiler
|
|
_task_executor_factory = executor.SerialTaskExecutor
|
|
|
|
def __init__(self, flow, flow_detail, backend, options):
|
|
super(ActionEngine, self).__init__(flow, flow_detail, backend, options)
|
|
self._runtime = None
|
|
self._compiled = False
|
|
self._compilation = None
|
|
self._lock = threading.RLock()
|
|
self._state_lock = threading.RLock()
|
|
self._storage_ensured = False
|
|
|
|
def __str__(self):
|
|
return "%s: %s" % (reflection.get_class_name(self), id(self))
|
|
|
|
def suspend(self):
|
|
if not self._compiled:
|
|
raise exc.InvalidState("Can not suspend an engine"
|
|
" which has not been compiled")
|
|
self._change_state(states.SUSPENDING)
|
|
|
|
@property
|
|
def compilation(self):
|
|
"""The compilation result.
|
|
|
|
NOTE(harlowja): Only accessible after compilation has completed (None
|
|
will be returned when this property is accessed before compilation has
|
|
completed successfully).
|
|
"""
|
|
if self._compiled:
|
|
return self._compilation
|
|
else:
|
|
return None
|
|
|
|
def run(self):
|
|
with lock_utils.try_lock(self._lock) as was_locked:
|
|
if not was_locked:
|
|
raise exc.ExecutionFailure("Engine currently locked, please"
|
|
" try again later")
|
|
for _state in self.run_iter():
|
|
pass
|
|
|
|
def run_iter(self, timeout=None):
|
|
"""Runs the engine using iteration (or die trying).
|
|
|
|
:param timeout: timeout to wait for any tasks to complete (this timeout
|
|
will be used during the waiting period that occurs after the
|
|
waiting state is yielded when unfinished tasks are being waited
|
|
for).
|
|
|
|
Instead of running to completion in a blocking manner, this will
|
|
return a generator which will yield back the various states that the
|
|
engine is going through (and can be used to run multiple engines at
|
|
once using a generator per engine). the iterator returned also
|
|
responds to the send() method from pep-0342 and will attempt to suspend
|
|
itself if a truthy value is sent in (the suspend may be delayed until
|
|
all active tasks have finished).
|
|
|
|
NOTE(harlowja): using the run_iter method will **not** retain the
|
|
engine lock while executing so the user should ensure that there is
|
|
only one entity using a returned engine iterator (one per engine) at a
|
|
given time.
|
|
"""
|
|
self.compile()
|
|
self.prepare()
|
|
runner = self._runtime.runner
|
|
last_state = None
|
|
with _start_stop(self._task_executor):
|
|
self._change_state(states.RUNNING)
|
|
try:
|
|
closed = False
|
|
for (last_state, failures) in runner.run_iter(timeout=timeout):
|
|
if failures:
|
|
misc.Failure.reraise_if_any(failures)
|
|
if closed:
|
|
continue
|
|
try:
|
|
try_suspend = yield last_state
|
|
except GeneratorExit:
|
|
# The generator was closed, attempt to suspend and
|
|
# continue looping until we have cleanly closed up
|
|
# shop...
|
|
closed = True
|
|
self.suspend()
|
|
else:
|
|
if try_suspend:
|
|
self.suspend()
|
|
except Exception:
|
|
with excutils.save_and_reraise_exception():
|
|
self._change_state(states.FAILURE)
|
|
else:
|
|
ignorable_states = getattr(runner, 'ignorable_states', [])
|
|
if last_state and last_state not in ignorable_states:
|
|
self._change_state(last_state)
|
|
if last_state not in [states.SUSPENDED, states.SUCCESS]:
|
|
failures = self.storage.get_failures()
|
|
misc.Failure.reraise_if_any(failures.values())
|
|
|
|
def _change_state(self, state):
|
|
with self._state_lock:
|
|
old_state = self.storage.get_flow_state()
|
|
if not states.check_flow_transition(old_state, state):
|
|
return
|
|
self.storage.set_flow_state(state)
|
|
details = {
|
|
'engine': self,
|
|
'flow_name': self.storage.flow_name,
|
|
'flow_uuid': self.storage.flow_uuid,
|
|
'old_state': old_state,
|
|
}
|
|
self.notifier.notify(state, details)
|
|
|
|
def _ensure_storage(self):
|
|
# NOTE(harlowja): signal to the tasks that exist that we are about to
|
|
# resume, if they have a previous state, they will now transition to
|
|
# a resuming state (and then to suspended).
|
|
self._change_state(states.RESUMING) # does nothing in PENDING state
|
|
for node in self._compilation.execution_graph.nodes_iter():
|
|
self.storage.ensure_atom(node)
|
|
if node.inject:
|
|
self.storage.inject_atom_args(node.name, node.inject)
|
|
self._change_state(states.SUSPENDED) # does nothing in PENDING state
|
|
|
|
@lock_utils.locked
|
|
def prepare(self):
|
|
if not self._compiled:
|
|
raise exc.InvalidState("Can not prepare an engine"
|
|
" which has not been compiled")
|
|
if not self._storage_ensured:
|
|
self._ensure_storage()
|
|
self._storage_ensured = True
|
|
# At this point we can check to ensure all dependencies are either
|
|
# flow/task provided or storage provided, if there are still missing
|
|
# dependencies then this flow will fail at runtime (which we can avoid
|
|
# by failing at preparation time).
|
|
external_provides = set(self.storage.fetch_all().keys())
|
|
missing = self._flow.requires - external_provides
|
|
if missing:
|
|
raise exc.MissingDependencies(self._flow, sorted(missing))
|
|
# Reset everything back to pending (if we were previously reverted).
|
|
if self.storage.get_flow_state() == states.REVERTED:
|
|
self._runtime.reset_all()
|
|
self._change_state(states.PENDING)
|
|
|
|
@misc.cachedproperty
|
|
def _task_executor(self):
|
|
return self._task_executor_factory()
|
|
|
|
@misc.cachedproperty
|
|
def _compiler(self):
|
|
return self._compiler_factory(self._flow)
|
|
|
|
@lock_utils.locked
|
|
def compile(self):
|
|
if self._compiled:
|
|
return
|
|
self._compilation = self._compiler.compile()
|
|
self._runtime = runtime.Runtime(self._compilation,
|
|
self.storage,
|
|
self.task_notifier,
|
|
self._task_executor)
|
|
self._compiled = True
|
|
|
|
|
|
class SerialActionEngine(ActionEngine):
|
|
"""Engine that runs tasks in serial manner."""
|
|
_storage_factory = atom_storage.SingleThreadedStorage
|
|
|
|
|
|
class ParallelActionEngine(ActionEngine):
|
|
"""Engine that runs tasks in parallel manner."""
|
|
_storage_factory = atom_storage.MultiThreadedStorage
|
|
|
|
def _task_executor_factory(self):
|
|
return executor.ParallelTaskExecutor(
|
|
executor=self._options.get('executor'),
|
|
max_workers=self._options.get('max_workers'))
|