OpenStack library for messaging
3f3c489aaf
This fixes a race due to the quirkiness of the blocking executor. The blocking executor does not create a separate thread, but is instead explicitly executed in the calling thread. Other threads will, however, continue to interact with it. In the non-blocking case, the executor will have done certain initialisation in start() before starting a worker thread and returning control to the caller. That is, the caller can be sure that this initialisation has occurred when control is returned. However, in the blocking case, control is never returned. We currently work round this by setting self._running to True before executing executor.start, and by not doing any locking whatsoever in MessageHandlingServer. However, this current means there is a race whereby executor.stop() can run before executor.start(). This is fragile and extremely difficult to reason about robustly, if not currently broken. The solution is to split the initialisation from the execution in the blocking case. executor.start() is no longer a blocking operation for the blocking executor. As for the non-blocking case, executor.start() returns as soon as initialisation is complete, indicating that it is safe to subsequently call stop(). Actual execution is done explicitly via the new execute() method, which blocks. In doing this, we also make FakeBlockingThread a more complete implementation of threading.Thread. This fixes a related issue in that, previously, calling server.wait() on a blocking executor from another thread would not wait for the completion of the executor. This has a knock-on effect in test_server's ServerSetupMixin. This mixin created an endpoint with a stop method which called server.stop(). However, as this is executed by the executor, and also joins the executor thread, which is now blocking, this results in a deadlock. I am satisfied that, in general, this is not a sane thing to do. However, it is useful for these tests. We fix the tests by making the stop method non-blocking, and do the actual stop and wait calls from the main thread. Change-Id: I0d332f74c06c22b44179319432153e15b69f2f45 |
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| doc/source | ||
| etc | ||
| oslo_messaging | ||
| oslo.messaging/locale | ||
| tools | ||
| .coveragerc | ||
| .gitignore | ||
| .gitreview | ||
| .testr.conf | ||
| babel.cfg | ||
| CONTRIBUTING.rst | ||
| LICENSE | ||
| MANIFEST.in | ||
| README.rst | ||
| requirements.txt | ||
| setup-test-env-qpid.sh | ||
| setup-test-env-rabbit.sh | ||
| setup-test-env-zmq.sh | ||
| setup.cfg | ||
| setup.py | ||
| test-requirements.txt | ||
| tox.ini | ||
Oslo Messaging Library
The Oslo messaging API supports RPC and notifications over a number of different messaging transports.
- License: Apache License, Version 2.0
- Documentation: http://docs.openstack.org/developer/oslo.messaging
- Source: http://git.openstack.org/cgit/openstack/oslo.messaging
- Bugs: http://bugs.launchpad.net/oslo.messaging