204 lines
6.5 KiB
Python
204 lines
6.5 KiB
Python
# 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 concurrent.futures
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import sys
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import threading
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import time
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import keystoneauth1.exceptions
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import six
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from openstack import exceptions
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from openstack import utils
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_log = utils.setup_logging(__name__)
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class Task(object):
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"""Represent a remote 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, main=None, name=None, run_async=False, *args, **kwargs):
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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._response = None
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self._finished = threading.Event()
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self._main = main
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self._run_async = run_async
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self.args = args
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self.kwargs = kwargs
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self.name = name or type(self).__name__
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def main(self):
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return self._main(*self.args, **self.kwargs)
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@property
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def run_async(self):
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return self._run_async
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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, raw=False):
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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):
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try:
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# Retry one time if we get a retriable connection failure
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try:
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self.done(self.main())
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except keystoneauth1.exceptions.RetriableConnectionFailure as e:
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self.done(self.main())
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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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def __init__(self, name, log=_log, workers=5, **kwargs):
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self.name = name
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self._executor = None
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self._log = log
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self._workers = workers
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@property
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def executor(self):
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if not self._executor:
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self._executor = concurrent.futures.ThreadPoolExecutor(
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max_workers=self._workers)
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return self._executor
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def stop(self):
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""" This is a direct action passthrough TaskManager """
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if self._executor:
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self._executor.shutdown()
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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 submit_task(self, task):
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"""Submit and execute the given task.
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:param task: The task to execute.
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:param bool raw: If True, return the raw result as received from the
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underlying client call.
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"""
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return self.run_task(task=task)
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def submit_function(self, method, name=None, *args, **kwargs):
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""" Allows submitting an arbitrary method for work.
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:param method: Callable to run in the TaskManager.
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:param str name: Name to use for the generated Task object.
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:param args: positional arguments to pass to the method when it runs.
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:param kwargs: keyword arguments to pass to the method when it runs.
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"""
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task = Task(main=method, name=name, *args, **kwargs)
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return self.submit_task(task)
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def submit_function_async(self, method, name=None, *args, **kwargs):
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""" Allows submitting an arbitrary method for async work scheduling.
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:param method: Callable to run in the TaskManager.
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:param str name: Name to use for the generated Task object.
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:param args: positional arguments to pass to the method when it runs.
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:param kwargs: keyword arguments to pass to the method when it runs.
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"""
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task = Task(method=method, name=name, run_async=True, **kwargs)
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return self.submit_task(task)
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def pre_run_task(self, task):
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self._log.debug(
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"Manager %s running task %s", self.name, task.name)
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def run_task(self, task):
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if task.run_async:
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return self._run_task_async(task)
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else:
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return self._run_task(task)
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def post_run_task(self, elapsed_time, task):
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self._log.debug(
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"Manager %s ran task %s in %ss",
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self.name, task.name, elapsed_time)
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def _run_task_async(self, task):
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self._log.debug(
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"Manager %s submitting task %s", self.name, task.name)
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return self.executor.submit(self._run_task, task)
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def _run_task(self, task):
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self.pre_run_task(task)
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start = time.time()
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task.run()
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end = time.time()
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dt = end - start
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self.post_run_task(dt, task)
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return task.wait()
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def wait_for_futures(futures, raise_on_error=True, log=_log):
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'''Collect results or failures from a list of running future tasks.'''
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results = []
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retries = []
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# Check on each result as its thread finishes
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for completed in concurrent.futures.as_completed(futures):
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try:
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result = completed.result()
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exceptions.raise_from_response(result)
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results.append(result)
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except (keystoneauth1.exceptions.RetriableConnectionFailure,
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exceptions.HttpException) as e:
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log.exception(
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"Exception processing async task: {e}".format(e=str(e)))
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if raise_on_error:
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raise
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# If we get an exception, put the result into a list so we
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# can try again
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retries.append(result)
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return results, retries
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