# -*- coding: utf-8 -*- # Copyright (C) 2014 Yahoo! Inc. All Rights Reserved. # # 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 from concurrent import futures import jsonschema from jsonschema import exceptions as schema_exc import six from taskflow.engines.action_engine import executor from taskflow import exceptions as excp from taskflow.types import time from taskflow.utils import misc from taskflow.utils import reflection # NOTE(skudriashev): This is protocol events, not related to the task states. WAITING = 'WAITING' PENDING = 'PENDING' RUNNING = 'RUNNING' SUCCESS = 'SUCCESS' FAILURE = 'FAILURE' PROGRESS = 'PROGRESS' # Remote task actions. EXECUTE = 'execute' REVERT = 'revert' # Remote task action to event map. ACTION_TO_EVENT = { EXECUTE: executor.EXECUTED, REVERT: executor.REVERTED } # NOTE(skudriashev): A timeout which specifies request expiration period. REQUEST_TIMEOUT = 60 # NOTE(skudriashev): A timeout which controls for how long a queue can be # unused before it is automatically deleted. Unused means the queue has no # consumers, the queue has not been redeclared, the `queue.get` has not been # invoked for a duration of at least the expiration period. In our case this # period is equal to the request timeout, once request is expired - queue is # no longer needed. QUEUE_EXPIRE_TIMEOUT = REQUEST_TIMEOUT # Workers notify period. NOTIFY_PERIOD = 5 # Message types. NOTIFY = 'NOTIFY' REQUEST = 'REQUEST' RESPONSE = 'RESPONSE' @six.add_metaclass(abc.ABCMeta) class Message(object): """Base class for all message types.""" def __str__(self): return "<%s> %s" % (self.TYPE, self.to_dict()) @abc.abstractmethod def to_dict(self): """Return json-serializable message representation.""" class Notify(Message): """Represents notify message type.""" TYPE = NOTIFY # NOTE(harlowja): the executor (the entity who initially requests a worker # to send back a notification response) schema is different than the # worker response schema (that's why there are two schemas here). _RESPONSE_SCHEMA = { "type": "object", 'properties': { 'topic': { "type": "string", }, 'tasks': { "type": "array", "items": { "type": "string", }, } }, "required": ["topic", 'tasks'], "additionalProperties": False, } _SENDER_SCHEMA = { "type": "object", "additionalProperties": False, } def __init__(self, **data): self._data = data def to_dict(self): return self._data @classmethod def validate(cls, data, response): if response: schema = cls._RESPONSE_SCHEMA else: schema = cls._SENDER_SCHEMA try: jsonschema.validate(data, schema) except schema_exc.ValidationError as e: if response: raise excp.InvalidFormat("%s message response data not of the" " expected format: %s" % (cls.TYPE, e.message), e) else: raise excp.InvalidFormat("%s message sender data not of the" " expected format: %s" % (cls.TYPE, e.message), e) class Request(Message): """Represents request with execution results. Every request is created in the WAITING state and is expired within the given timeout. """ TYPE = REQUEST def __init__(self, task, uuid, action, arguments, progress_callback, timeout, **kwargs): self._task = task self._task_cls = reflection.get_class_name(task) self._uuid = uuid self._action = action self._event = ACTION_TO_EVENT[action] self._arguments = arguments self._progress_callback = progress_callback self._kwargs = kwargs self._watch = time.StopWatch(duration=timeout).start() self._state = WAITING self.result = futures.Future() def __repr__(self): return "%s:%s" % (self._task_cls, self._action) @property def uuid(self): return self._uuid @property def task_cls(self): return self._task_cls @property def state(self): return self._state @property def expired(self): """Check if request has expired. When new request is created its state is set to the WAITING, creation time is stored and timeout is given via constructor arguments. Request is considered to be expired when it is in the WAITING/PENDING state for more then the given timeout (it is not considered to be expired in any other state). """ if self._state in (WAITING, PENDING): return self._watch.expired() return False def to_dict(self): """Return json-serializable request. To convert requests that have failed due to some exception this will convert all `misc.Failure` objects into dictionaries (which will then be reconstituted by the receiver). """ request = dict(task_cls=self._task_cls, task_name=self._task.name, task_version=self._task.version, action=self._action, arguments=self._arguments) if 'result' in self._kwargs: result = self._kwargs['result'] if isinstance(result, misc.Failure): request['result'] = ('failure', result.to_dict()) else: request['result'] = ('success', result) if 'failures' in self._kwargs: failures = self._kwargs['failures'] request['failures'] = {} for task, failure in six.iteritems(failures): request['failures'][task] = failure.to_dict() return request def set_result(self, result): self.result.set_result((self._task, self._event, result)) def set_pending(self): self._state = PENDING def set_running(self): self._state = RUNNING self._watch.stop() def on_progress(self, event_data, progress): self._progress_callback(self._task, event_data, progress) class Response(Message): """Represents response message type.""" TYPE = RESPONSE def __init__(self, state, **data): self._state = state self._data = data @classmethod def from_dict(cls, data): state = data['state'] data = data['data'] if state == FAILURE and 'result' in data: data['result'] = misc.Failure.from_dict(data['result']) return cls(state, **data) @property def state(self): return self._state @property def data(self): return self._data def to_dict(self): return dict(state=self._state, data=self._data)