| # Licensed to the Apache Software Foundation (ASF) under one or more |
| # contributor license agreements. See the NOTICE file distributed with |
| # this work for additional information regarding copyright ownership. |
| # The ASF licenses this file to You 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. |
| |
| """ |
| The workflow engine. Executes workflows |
| """ |
| |
| import time |
| from datetime import datetime |
| |
| from aria import logger |
| from aria.modeling import models |
| from aria.orchestrator import events |
| from aria.orchestrator.context import operation |
| |
| from .. import exceptions |
| from ..executor.base import StubTaskExecutor |
| # Import required so all signals are registered |
| from . import events_handler # pylint: disable=unused-import |
| |
| |
| class Engine(logger.LoggerMixin): |
| """ |
| The workflow engine. Executes workflows |
| """ |
| |
| def __init__(self, executors, **kwargs): |
| super(Engine, self).__init__(**kwargs) |
| self._executors = executors.copy() |
| self._executors.setdefault(StubTaskExecutor, StubTaskExecutor()) |
| |
| def execute(self, ctx, resuming=False): |
| """ |
| execute the workflow |
| """ |
| if resuming: |
| events.on_resume_workflow_signal.send(ctx) |
| |
| tasks_tracker = _TasksTracker(ctx) |
| try: |
| events.start_workflow_signal.send(ctx) |
| while True: |
| cancel = self._is_cancel(ctx) |
| if cancel: |
| break |
| for task in tasks_tracker.ended_tasks: |
| self._handle_ended_tasks(task) |
| tasks_tracker.finished(task) |
| for task in tasks_tracker.executable_tasks: |
| tasks_tracker.executing(task) |
| self._handle_executable_task(ctx, task) |
| if tasks_tracker.all_tasks_consumed: |
| break |
| else: |
| time.sleep(0.1) |
| if cancel: |
| self._terminate_tasks(tasks_tracker.executing_tasks) |
| events.on_cancelled_workflow_signal.send(ctx) |
| else: |
| events.on_success_workflow_signal.send(ctx) |
| except BaseException as e: |
| # Cleanup any remaining tasks |
| self._terminate_tasks(tasks_tracker.executing_tasks) |
| events.on_failure_workflow_signal.send(ctx, exception=e) |
| raise |
| |
| def _terminate_tasks(self, tasks): |
| for task in tasks: |
| try: |
| self._executors[task._executor].terminate(task.id) |
| except BaseException: |
| pass |
| |
| @staticmethod |
| def cancel_execution(ctx): |
| """ |
| Send a cancel request to the engine. If execution already started, execution status |
| will be modified to 'cancelling' status. If execution is in pending mode, execution status |
| will be modified to 'cancelled' directly. |
| """ |
| events.on_cancelling_workflow_signal.send(ctx) |
| |
| @staticmethod |
| def _is_cancel(ctx): |
| execution = ctx.model.execution.refresh(ctx.execution) |
| return execution.status in (models.Execution.CANCELLING, models.Execution.CANCELLED) |
| |
| def _handle_executable_task(self, ctx, task): |
| task_executor = self._executors[task._executor] |
| |
| # If the task is a stub, a default context is provided, else it should hold the context cls |
| context_cls = operation.BaseOperationContext if task._stub_type else task._context_cls |
| op_ctx = context_cls( |
| model_storage=ctx.model, |
| resource_storage=ctx.resource, |
| workdir=ctx._workdir, |
| task_id=task.id, |
| actor_id=task.actor.id if task.actor else None, |
| service_id=task.execution.service.id, |
| execution_id=task.execution.id, |
| name=task.name |
| ) |
| |
| if not task._stub_type: |
| events.sent_task_signal.send(op_ctx) |
| task_executor.execute(op_ctx) |
| |
| @staticmethod |
| def _handle_ended_tasks(task): |
| if task.status == models.Task.FAILED and not task.ignore_failure: |
| raise exceptions.ExecutorException('Workflow failed') |
| |
| |
| class _TasksTracker(object): |
| def __init__(self, ctx): |
| self._ctx = ctx |
| self._tasks = ctx.execution.tasks |
| self._executed_tasks = [task for task in self._tasks if task.has_ended()] |
| self._executable_tasks = list(set(self._tasks) - set(self._executed_tasks)) |
| self._executing_tasks = [] |
| |
| @property |
| def all_tasks_consumed(self): |
| return len(self._executed_tasks) == len(self._tasks) and len(self._executing_tasks) == 0 |
| |
| def executing(self, task): |
| # Task executing could be retrying (thus removed and added earlier) |
| if task not in self._executing_tasks: |
| self._executable_tasks.remove(task) |
| self._executing_tasks.append(task) |
| |
| def finished(self, task): |
| self._executing_tasks.remove(task) |
| self._executed_tasks.append(task) |
| |
| @property |
| def ended_tasks(self): |
| for task in self.executing_tasks: |
| if task.has_ended(): |
| yield task |
| |
| @property |
| def executable_tasks(self): |
| now = datetime.utcnow() |
| # we need both lists since retrying task are in the executing task list. |
| for task in self._update_tasks(self._executing_tasks + self._executable_tasks): |
| if all([task.is_waiting(), |
| task.due_at <= now, |
| all(dependency in self._executed_tasks for dependency in task.dependencies) |
| ]): |
| yield task |
| |
| @property |
| def executing_tasks(self): |
| for task in self._update_tasks(self._executing_tasks): |
| yield task |
| |
| @property |
| def executed_tasks(self): |
| for task in self._update_tasks(self._executed_tasks): |
| yield task |
| |
| @property |
| def tasks(self): |
| for task in self._update_tasks(self._tasks): |
| yield task |
| |
| def _update_tasks(self, tasks): |
| for task in tasks: |
| yield self._ctx.model.task.refresh(task) |