c558da07b6
Update hacking to the new requirements version and
fix about half of the new reported issues. The other
hacking issues are for now ignored until fixed by
adjusting our tox.ini file.
This commit fixes the following new hacking errors:
H405 - multi line docstring summary not separated
with an empty line
E265 - block comment should start with '# '
F402 - import 'endpoint' from line 21 shadowed by
loop variable
Change-Id: I6bae61591fb988cc17fa79e21cb5f1508d22781c
118 lines
4.7 KiB
Python
118 lines
4.7 KiB
Python
# -*- coding: utf-8 -*-
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import abc
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import threading
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import six
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import taskflow.engines
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from taskflow import exceptions as excp
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from taskflow.utils import lock_utils
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@six.add_metaclass(abc.ABCMeta)
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class Conductor(object):
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"""Conductors conduct jobs & assist in associated runtime interactions.
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Conductors act as entities which extract jobs from a jobboard, assign
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there work to some engine (using some desired configuration) and then wait
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for that work to complete. If the work fails then they abandon the claimed
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work (or if the process they are running in crashes or dies this
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abandonment happens automatically) and then another conductor at a later
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period of time will finish up the prior failed conductors work.
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"""
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def __init__(self, name, jobboard, engine_conf, persistence):
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self._name = name
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self._jobboard = jobboard
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self._engine_conf = engine_conf
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self._persistence = persistence
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self._lock = threading.RLock()
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def _flow_detail_from_job(self, job):
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"""Extracts a flow detail from a job (via some manner).
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The current mechanism to accomplish this is the following choices:
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* If the job details provide a 'flow_uuid' key attempt to load this
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key from the jobs book and use that as the flow_detail to run.
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* If the job details does not have have a 'flow_uuid' key then attempt
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to examine the size of the book and if it's only one element in the
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book (aka one flow_detail) then just use that.
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* Otherwise if there is no 'flow_uuid' defined or there are > 1
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flow_details in the book raise an error that corresponds to being
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unable to locate the correct flow_detail to run.
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"""
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book = job.book
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if book is None:
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raise excp.NotFound("No book found in job")
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if job.details and 'flow_uuid' in job.details:
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flow_uuid = job.details["flow_uuid"]
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flow_detail = book.find(flow_uuid)
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if flow_detail is None:
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raise excp.NotFound("No matching flow detail found in"
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" jobs book for flow detail"
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" with uuid %s" % flow_uuid)
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else:
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choices = len(book)
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if choices == 1:
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flow_detail = list(book)[0]
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elif choices == 0:
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raise excp.NotFound("No flow detail(s) found in jobs book")
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else:
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raise excp.MultipleChoices("No matching flow detail found (%s"
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" choices) in jobs book" % choices)
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return flow_detail
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def _engine_from_job(self, job):
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"""Extracts an engine from a job (via some manner)."""
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flow_detail = self._flow_detail_from_job(job)
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if job.details and 'store' in job.details:
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store = dict(job.details["store"])
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else:
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store = {}
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return taskflow.engines.load_from_detail(flow_detail,
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store=store,
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engine_conf=self._engine_conf,
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backend=self._persistence)
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@lock_utils.locked
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def connect(self):
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"""Ensures the jobboard is connected (noop if it is already)."""
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if not self._jobboard.connected:
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self._jobboard.connect()
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@lock_utils.locked
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def close(self):
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"""Closes the jobboard, disallowing further use."""
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self._jobboard.close()
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@abc.abstractmethod
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def run(self):
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"""Continuously claims, runs, and consumes jobs (and repeat)."""
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@abc.abstractmethod
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def _dispatch_job(self, job):
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"""Dispatches a claimed job for work completion.
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Accepts a single (already claimed) job and causes it to be run in
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an engine. Returns a boolean that signifies whether the job should
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be consumed. The job is consumed upon completion (unless False is
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returned which will signify the job should be abandoned instead).
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:param job: A job instance that has already been claimed by the
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jobboard.
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"""
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