deb-mistral/mistral/engine/base.py

220 lines
7.0 KiB
Python

# -*- coding: utf-8 -*-
#
# Copyright 2014 - 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.
import abc
import jsonschema
import six
from mistral import exceptions as exc
from mistral.utils import inspect_utils
from mistral.workflow import data_flow
@six.add_metaclass(abc.ABCMeta)
class Engine(object):
"""Engine interface."""
@abc.abstractmethod
def start_workflow(self, wf_identifier, wf_input, description='',
**params):
"""Starts the specified workflow.
:param wf_identifier: Workflow ID or name. Workflow ID is recommended,
workflow name will be deprecated since Mitaka.
:param wf_input: Workflow input data as a dictionary.
:param description: Execution description.
:param params: Additional workflow type specific parameters.
:return: Workflow execution object.
"""
raise NotImplementedError
@abc.abstractmethod
def start_action(self, action_name, action_input,
description=None, **params):
"""Starts the specific action.
:param action_name: Action name.
:param action_input: Action input data as a dictionary.
:param description: Execution description.
:param params: Additional options for action running.
:return: Action execution object.
"""
raise NotImplementedError
@abc.abstractmethod
def on_action_complete(self, action_ex_id, result, wf_action=False):
"""Accepts action result and continues the workflow.
Action execution result here is a result which comes from an
action/workflow associated which the task.
:param action_ex_id: Action execution id.
:param result: Action/workflow result. Instance of
mistral.workflow.base.Result
:param wf_action: If True it means that the given id points to
a workflow execution rather than action execution. It happens
when a nested workflow execution sends its result to a parent
workflow.
:return: Action(or workflow if wf_action=True) execution object.
"""
raise NotImplementedError
@abc.abstractmethod
def pause_workflow(self, wf_ex_id):
"""Pauses workflow.
:param wf_ex_id: Execution id.
:return: Workflow execution object.
"""
raise NotImplementedError
@abc.abstractmethod
def resume_workflow(self, wf_ex_id, env=None):
"""Resumes workflow.
:param wf_ex_id: Execution id.
:param env: Workflow environment.
:return: Workflow execution object.
"""
raise NotImplementedError
@abc.abstractmethod
def rerun_workflow(self, task_ex_id, reset=True, env=None):
"""Rerun workflow from the specified task.
:param task_ex_id: Task execution id.
:param reset: If True, reset task state including deleting its action
executions.
:param env: Workflow environment.
:return: Workflow execution object.
"""
raise NotImplementedError
@abc.abstractmethod
def stop_workflow(self, wf_ex_id, state, message):
"""Stops workflow.
:param wf_ex_id: Workflow execution id.
:param state: State assigned to the workflow. Permitted states are
SUCCESS or ERROR.
:param message: Optional information string.
:return: Workflow execution.
"""
raise NotImplementedError
@abc.abstractmethod
def rollback_workflow(self, wf_ex_id):
"""Rolls back workflow execution.
:param wf_ex_id: Execution id.
:return: Workflow execution object.
"""
raise NotImplementedError
@six.add_metaclass(abc.ABCMeta)
class Executor(object):
"""Action executor interface."""
@abc.abstractmethod
def run_action(self, action_ex_id, action_class_str, attributes,
action_params, safe_rerun, redelivered=False):
"""Runs action.
:param action_ex_id: Corresponding action execution id.
:param action_class_str: Path to action class in dot notation.
:param attributes: Attributes of action class which will be set to.
:param action_params: Action parameters.
:param safe_rerun: Tells if given action can be safely rerun.
:param redelivered: Tells if given action was run before on another
executor.
"""
raise NotImplementedError()
@six.add_metaclass(abc.ABCMeta)
class EventEngine(object):
"""Action event trigger interface."""
@abc.abstractmethod
def create_event_trigger(self, trigger, events):
raise NotImplementedError()
@abc.abstractmethod
def delete_event_trigger(self, trigger, events):
raise NotImplementedError()
@six.add_metaclass(abc.ABCMeta)
class TaskPolicy(object):
"""Task policy.
Provides interface to perform any work after a task has completed.
An example of task policy may be 'retry' policy that makes engine
to run a task repeatedly if it finishes with a failure.
"""
_schema = {}
def before_task_start(self, task_ex, task_spec):
"""Called right before task start.
:param task_ex: DB model for task that is about to start.
:param task_spec: Task specification.
"""
wf_ex = task_ex.workflow_execution
ctx_view = data_flow.ContextView(
task_ex.in_context,
wf_ex.context,
wf_ex.input
)
data_flow.evaluate_object_fields(self, ctx_view)
self._validate()
def after_task_complete(self, task_ex, task_spec):
"""Called right after task completes.
:param task_ex: Completed task DB model.
:param task_spec: Completed task specification.
"""
wf_ex = task_ex.workflow_execution
ctx_view = data_flow.ContextView(
task_ex.in_context,
wf_ex.context,
wf_ex.input
)
data_flow.evaluate_object_fields(self, ctx_view)
self._validate()
def _validate(self):
"""Validation of types after YAQL evaluation."""
props = inspect_utils.get_public_fields(self)
try:
jsonschema.validate(props, self._schema)
except Exception as e:
raise exc.InvalidModelException(
"Invalid data type in %s: %s. Value(s) can be shown after "
"YAQL evaluating. If you use YAQL here, please correct it."
% (self.__class__.__name__, e.message)
)