deb-mistral/mistral/engine/action_handler.py
Renat Akhmerov 816bfd9dcc Refactor Mistral Engine
* Introduced class hierarchies Task and Action used by Mistral engine.
  Note: Action here is a different than executor Action and represents
  rather actions of different types: regular python action, ad-hoc
  action and workflow action (since for task action and workflow are
  polymorphic)
* Refactored task_handler.py and action_handler.py with Task and Action
  hierarchies
* Rebuilt a chain call so that the entire action processing would look
  like a chain of calls Action -> Task -> Workflow where each level
  knows only about the next level and can influence it (e.g. if adhoc
  action has failed due to YAQL error in 'output' transformer action
  itself fails its task)
* Refactored policies according to new object model
* Fixed some of the tests to match the idea of having two types of
  exceptions, MistralException and MistralError, where the latter
  is considered either a harsh environmental problem or a logical
  issue in the system itself so that it must not be handled anywhere
  in the code

TODO(in subsequent patches):
 * Refactor WithItemsTask w/o using with_items.py
 * Remove DB transaction in Scheduler when making a delayed call,
   helper policy methods like 'continue_workflow'
 * Refactor policies test so that workflow definitions live right
   in test methods
 * Refactor workflow_handler with Workflow abstraction
 * Get rid of RunExistingTask workflow command, it should be just
   one command with various properties
 * Refactor resume and rerun with Task abstraction (same way as
   other methods, e.g. on_action_complete())
 * Add error handling to all required places such as
   task_handler.continue_task()
 * More tests for error handling

P.S. This patch is very big but it was nearly impossible to split
it into multiple smaller patches just because how entangled everything
was in Mistral Engine.

Partially implements: blueprint mistral-engine-error-handling
Implements: blueprint mistral-action-result-processing-pipeline
Implements: blueprint mistral-refactor-task-handler
Closes-Bug: #1568909

Change-Id: I0668e695c60dde31efc690563fc891387d44d6ba
2016-05-31 14:08:36 +00:00

93 lines
2.6 KiB
Python

# Copyright 2015 - Mirantis, Inc.
#
# 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 oslo_log import log as logging
import traceback as tb
from mistral.db.v2.sqlalchemy import models
from mistral.engine import actions
from mistral.engine import task_handler
from mistral import exceptions as exc
from mistral.workbook import parser as spec_parser
LOG = logging.getLogger(__name__)
def on_action_complete(action_ex, result):
task_ex = action_ex.task_execution
action = _build_action(action_ex)
try:
action.complete(result)
except exc.MistralException as e:
msg = ("Failed to complete action [action=%s, task=%s]: %s\n%s" %
(action_ex.name, task_ex.name, e, tb.format_exc()))
LOG.error(msg)
action.fail(msg)
if task_ex:
task_handler.fail_task(task_ex, msg)
return
if task_ex:
task_handler.on_action_complete(action_ex)
def _build_action(action_ex):
if isinstance(action_ex, models.WorkflowExecution):
return actions.WorkflowAction(None, action_ex=action_ex)
wf_name = None
wf_spec_name = None
if action_ex.workflow_name:
wf_name = action_ex.workflow_name
wf_spec = spec_parser.get_workflow_spec(
action_ex.task_execution.workflow_execution.spec
)
wf_spec_name = wf_spec.get_name()
adhoc_action_name = action_ex.runtime_context.get('adhoc_action_name')
if adhoc_action_name:
action_def = actions.resolve_action_definition(
adhoc_action_name,
wf_name,
wf_spec_name
)
return actions.AdHocAction(action_def, action_ex=action_ex)
action_def = actions.resolve_action_definition(
action_ex.name,
wf_name,
wf_spec_name
)
return actions.PythonAction(action_def, action_ex=action_ex)
def build_action_by_name(action_name):
action_def = actions.resolve_action_definition(action_name)
action_cls = (actions.PythonAction if not action_def.spec
else actions.AdHocAction)
return action_cls(action_def)