deb-mistral/mistral/workflow/states.py
Renat Akhmerov e2c89f777d Refactoring workflow handler
* Introduced new class Workflow that manages life-cycle of running
  workflows and is responsible for managing workflow persistent state
* Moved all workflow level logic to workflow handler and Workflow class
* Changed semantics if how workflows start errors are handled.
  Previously, in case of invalid user input Mistral engine would store
  information about error in "state_info" field of workflow execution
  and bubble up an exception to the user. This approach was incorrect
  for a number of reasons including broken semantics: if an exception
  was raised due to invalid input it's normal to expect that system
  state has not changed. After this refactoring, engine only raises
  an exception in case of bad user input. That way behavior is
  consistent with the idea of exceptional situations.
* Fixed unit tests in according to the previous point
* Fixed a number of logical issues in tests. For example, in
  test_default_engine.py we expected one type of errors (e.g. env not
  found) but effectively received another one (invalid input).

Partially implements: blueprint mistral-engine-error-handling

Change-Id: I09070411fd833df8284cb80db69b8401a40eb6fe
2016-06-07 18:38:38 +07:00

84 lines
1.9 KiB
Python

# -*- coding: utf-8 -*-
#
# Copyright 2013 - 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.
"""Valid task and workflow states."""
IDLE = 'IDLE'
WAITING = 'WAITING'
RUNNING = 'RUNNING'
RUNNING_DELAYED = 'DELAYED'
PAUSED = 'PAUSED'
SUCCESS = 'SUCCESS'
ERROR = 'ERROR'
_ALL = [IDLE, WAITING, RUNNING, SUCCESS, ERROR, PAUSED, RUNNING_DELAYED]
_VALID_TRANSITIONS = {
IDLE: [RUNNING, ERROR],
WAITING: [RUNNING],
RUNNING: [PAUSED, RUNNING_DELAYED, SUCCESS, ERROR],
RUNNING_DELAYED: [RUNNING, ERROR],
PAUSED: [RUNNING, ERROR],
SUCCESS: [],
ERROR: [RUNNING]
}
def is_valid(state):
return state in _ALL
def is_invalid(state):
return not is_valid(state)
def is_completed(state):
return state in [SUCCESS, ERROR]
def is_running(state):
return state in [RUNNING, RUNNING_DELAYED]
def is_waiting(state):
return state == WAITING
def is_idle(state):
return state == IDLE
def is_paused(state):
return state == PAUSED
def is_paused_or_completed(state):
return is_paused(state) or is_completed(state)
def is_paused_or_idle(state):
return is_paused(state) or is_idle(state)
def is_valid_transition(from_state, to_state):
if is_invalid(from_state) or is_invalid(to_state):
return False
if from_state == to_state:
return True
return to_state in _VALID_TRANSITIONS[from_state]