Fix flaky TestPollingChecker in health package #81
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…obe and it being cancelled by concurrent call to prober.Close()
jhump
commented
May 12, 2025
| // StateUnhealthy (HTTP error) | ||
| connection := make(fakeConnChan) | ||
| close(connection) | ||
| err := checker.New(ctx, connection, tracker).Close() |
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The call to New spawns a goroutine that launches a probe. But we'd then immediately call Close(), which cancels the prober's context. Both the prober goroutine and this test goroutine are running concurrently, so it's a race as to whether the initial probe can complete before the context is cancelled.
jhump
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ghost
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May 13, 2025
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Very tricky. Hopefully this is solid now.
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The previous formulation had a race condition between the prober completing its first probe in one goroutine and it being cancelled by a concurrent goroutine calling the
Close()function (which would cancel the prober's context).You can see two failures in a row here:
https://github.com/bufbuild/httplb/actions/runs/14962744579/attempts/3
It would also happen pretty reliable if you did
go test ./health -count 10. So I'm a little surprised we haven't seen this flake be more of an issue. It's possible that the context-related fix in the PR from that failed CI run (#80) actually tickled things just enough to make it happen more frequently.