deb-mistral/mistral/engine/default_executor.py
Renat Akhmerov 5fd47d5164 Handling MistralException in default executor
* This is needed to account for serialization errors (and similar)
  in case if an action returns bad data.

Closes-Bug: #1645649
Change-Id: I2e086e1829381d3d021e4c1f21c008f7ed10dca7
2016-12-06 14:42:30 +07:00

140 lines
5.1 KiB
Python

# Copyright 2013 - Mirantis, Inc.
# Copyright 2016 - Brocade Communications Systems, 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.
from oslo_log import log as logging
from osprofiler import profiler
from mistral.actions import action_factory as a_f
from mistral.engine import base
from mistral.engine.rpc_backend import rpc
from mistral import exceptions as exc
from mistral.utils import inspect_utils as i_u
from mistral.workflow import utils as wf_utils
LOG = logging.getLogger(__name__)
class DefaultExecutor(base.Executor):
def __init__(self):
self._engine_client = rpc.get_engine_client()
@profiler.trace('executor-run-action')
def run_action(self, action_ex_id, action_class_str, attributes,
action_params, safe_rerun, redelivered=False):
"""Runs action.
:param action_ex_id: 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.
"""
def send_error_back(error_msg):
error_result = wf_utils.Result(error=error_msg)
if action_ex_id:
self._engine_client.on_action_complete(
action_ex_id,
error_result
)
return None
return error_result
if redelivered and not safe_rerun:
msg = (
"Request to run action %s was redelivered, but action %s"
" cannot be re-run safely. The only safe thing to do is fail"
" action."
% (action_class_str, action_class_str)
)
return send_error_back(msg)
action_cls = a_f.construct_action_class(action_class_str, attributes)
# Instantiate action.
try:
action = action_cls(**action_params)
except Exception as e:
msg = ("Failed to initialize action %s. Action init params = %s."
" Actual init params = %s. More info: %s"
% (action_class_str, i_u.get_arg_list(action_cls.__init__),
action_params.keys(), e))
LOG.warning(msg)
return send_error_back(msg)
# Run action.
try:
result = action.run()
# Note: it's made for backwards compatibility with already
# existing Mistral actions which don't return result as
# instance of workflow.utils.Result.
if not isinstance(result, wf_utils.Result):
result = wf_utils.Result(data=result)
except Exception as e:
msg = ("Failed to run action [action_ex_id=%s, action_cls='%s',"
" attributes='%s', params='%s']\n %s"
% (action_ex_id, action_cls, attributes, action_params, e))
LOG.exception(msg)
return send_error_back(msg)
# Send action result.
try:
if action_ex_id and (action.is_sync() or result.is_error()):
self._engine_client.on_action_complete(
action_ex_id,
result,
async=True
)
except exc.MistralException as e:
# In case of a Mistral exception we can try to send error info to
# engine because most likely it's not related to the infrastructure
# such as message bus or network. One known case is when the action
# returns a bad result (e.g. invalid unicode) which can't be
# serialized.
msg = ("Failed to call engine's on_action_complete() method due"
" to a Mistral exception"
" [action_ex_id=%s, action_cls='%s',"
" attributes='%s', params='%s']\n %s"
% (action_ex_id, action_cls, attributes, action_params, e))
LOG.exception(msg)
return send_error_back(msg)
except Exception as e:
# If it's not a Mistral exception all we can do is only
# log the error.
msg = ("Failed to call engine's on_action_complete() method due"
" to an unexpected exception"
" [action_ex_id=%s, action_cls='%s',"
" attributes='%s', params='%s']\n %s"
% (action_ex_id, action_cls, attributes, action_params, e))
LOG.exception(msg)
return result