3f5092d7f4
Currently it is not possible to provide any reasonable output in case of a task or workflow failure. Implementing this would greatly simplify error handling in workflows. This blueprint is a proposal to introduce two new attributes, publish-on-error for tasks and output-on-error for workflows for this purpose. Implements: blueprint mistral-publish-on-error Change-Id: Ib3a64971effb02390206dc6f993e772a51f8f237
114 lines
3.4 KiB
Python
114 lines
3.4 KiB
Python
# Copyright 2015 - Mirantis, Inc.
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# Copyright 2015 - StackStorm, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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The intention of the module is providing various DB related lookup functions
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for more convenient usage withing the workflow engine.
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Some of the functions may provide caching capabilities.
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WARNING: Oftentimes, persistent objects returned by the methods in this
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module won't be attached to the current DB SQLAlchemy session because
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they are returned from the cache and therefore they need to be used
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carefully without trying to do any lazy loading etc.
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These objects are also not suitable for re-attaching them to a session
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in order to update their persistent DB state.
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Mostly, they are useful for doing any kind of fast lookups with in order
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to make some decision based on their state.
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"""
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import cachetools
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import threading
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from mistral.db.v2 import api as db_api
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from mistral.workflow import states
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_TASK_EXECUTIONS_CACHE_LOCK = threading.RLock()
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_TASK_EXECUTIONS_CACHE = cachetools.LRUCache(maxsize=20000)
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def find_task_executions_by_name(wf_ex_id, task_name):
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"""Finds task executions by workflow execution id and task name.
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:param wf_ex_id: Workflow execution id.
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:param task_name: Task name.
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:return: Task executions (possibly a cached value).
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"""
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cache_key = (wf_ex_id, task_name)
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with _TASK_EXECUTIONS_CACHE_LOCK:
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t_execs = _TASK_EXECUTIONS_CACHE.get(cache_key)
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if t_execs:
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return t_execs
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t_execs = db_api.get_task_executions(
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workflow_execution_id=wf_ex_id,
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name=task_name
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)
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# We can cache only finished tasks because they won't change.
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all_finished = (
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t_execs and
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all([states.is_completed(t_ex.state) for t_ex in t_execs])
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)
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if all_finished:
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with _TASK_EXECUTIONS_CACHE_LOCK:
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_TASK_EXECUTIONS_CACHE[cache_key] = t_execs
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return t_execs
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def find_task_executions_by_spec(wf_ex_id, task_spec):
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return find_task_executions_by_name(wf_ex_id, task_spec.get_name())
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def find_task_executions_by_specs(wf_ex_id, task_specs):
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res = []
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for t_s in task_specs:
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res = res + find_task_executions_by_spec(wf_ex_id, t_s)
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return res
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def find_task_executions_with_state(wf_ex_id, state):
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return db_api.get_task_executions(
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workflow_execution_id=wf_ex_id,
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state=state
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)
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def find_successful_task_executions(wf_ex_id):
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return find_task_executions_with_state(wf_ex_id, states.SUCCESS)
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def find_error_task_executions(wf_ex_id):
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return find_task_executions_with_state(wf_ex_id, states.ERROR)
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def find_cancelled_task_executions(wf_ex_id):
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return find_task_executions_with_state(wf_ex_id, states.CANCELLED)
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def find_completed_tasks(wf_ex_id):
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return db_api.get_completed_task_executions(workflow_execution_id=wf_ex_id)
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def clean_caches():
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with _TASK_EXECUTIONS_CACHE_LOCK:
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_TASK_EXECUTIONS_CACHE.clear()
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