fix: HTTPTransport.Flush panic and data race #140
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There are no automated tests covering the Would love some ideas in that regard. Thinking of testing some properties of Flush, like:
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untitaker
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I've included a few tests to exercise |
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bruno-garcia
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rhcarvalho
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Jan 22, 2020
The ConcurrentSendAndFlush test reveals a data race in the HTTPTransport implementation.
Rewrite HTTPTransport internals to remove a data race and occasional panics. Prior to this, HTTPTransport used a `sync.WaitGroup` to track how many in-flight requests existed, and `Flush` waited until the observed number of in-flight requests reached zero. Unsynchronized access to the WaitGroup lead to panics (reuse before wg.Wait returns) and data races (undefined order of wg.Add and wg.Wait calls). The new implementation changes the `Flush` behavior to wait until the current in-flight requests are processed, inline with other SDKs and the Unified API.
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Added more code comments describing how the mechanism works and what invariants are considered. Renamed and reorganized test code based on code review in person with @bruno-garcia. Thanks @bruno-garcia!!! |
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Rewrite HTTPTransport internals to remove a data race and occasional
panics.
Prior to this, HTTPTransport used a
sync.WaitGroupto track how manyin-flight requests existed, and
Flushwaited until the observed numberof in-flight requests reached zero.
Unsynchronized access to the WaitGroup lead to panics (reuse before
wg.Wait returns) and data races (undefined order of wg.Add and wg.Wait
calls). See #103 (comment), #103 (comment) and #103 (comment).
The new implementation changes the
Flushbehavior to wait until thecurrent in-flight requests are processed, inline with other SDKs and the
Unified API.
Fixes #103.