105 lines
3.1 KiB
Python
105 lines
3.1 KiB
Python
#!/usr/bin/env python
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# Copyright (C) 2011-2013 OpenStack Foundation
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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#
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import abc
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import sys
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import threading
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import time
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import six
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from shade import _log
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@six.add_metaclass(abc.ABCMeta)
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class Task(object):
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"""Represent a task to be performed on an OpenStack Cloud.
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Some consumers need to inject things like rate-limiting or auditing
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around each external REST interaction. Task provides an interface
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to encapsulate each such interaction. Also, although shade itself
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operates normally in a single-threaded direct action manner, consuming
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programs may provide a multi-threaded TaskManager themselves. For that
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reason, Task uses threading events to ensure appropriate wait conditions.
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These should be a no-op in single-threaded applications.
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A consumer is expected to overload the main method.
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:param dict kw: Any args that are expected to be passed to something in
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the main payload at execution time.
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"""
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def __init__(self, **kw):
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self._exception = None
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self._traceback = None
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self._result = None
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self._finished = threading.Event()
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self.args = kw
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@abc.abstractmethod
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def main(self, client):
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""" Override this method with the actual workload to be performed """
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def done(self, result):
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self._result = result
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self._finished.set()
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def exception(self, e, tb):
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self._exception = e
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self._traceback = tb
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self._finished.set()
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def wait(self):
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self._finished.wait()
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if self._exception:
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six.reraise(type(self._exception), self._exception,
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self._traceback)
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return self._result
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def run(self, client):
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try:
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self.done(self.main(client))
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except Exception as e:
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self.exception(e, sys.exc_info()[2])
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class TaskManager(object):
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log = _log.setup_logging("shade.TaskManager")
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def __init__(self, client, name):
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self.name = name
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self._client = client
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def stop(self):
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""" This is a direct action passthrough TaskManager """
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pass
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def run(self):
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""" This is a direct action passthrough TaskManager """
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pass
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def submitTask(self, task):
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self.log.debug(
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"Manager %s running task %s" % (self.name, type(task).__name__))
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start = time.time()
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task.run(self._client)
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end = time.time()
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self.log.debug(
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"Manager %s ran task %s in %ss" % (self.name, task, (end - start)))
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return task.wait()
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