[Merged by Bors] - p2p: server: close streams upon context cancellation #5981
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Also, cancel the context provided to the server handlers when the handler finishes.
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Additional details and impacted files@@ Coverage Diff @@
## develop #5981 +/- ##
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+ Coverage 80.7% 81.1% +0.3%
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Files 288 292 +4
Lines 29894 30860 +966
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+ Hits 24149 25043 +894
- Misses 4158 4182 +24
- Partials 1587 1635 +48 ☔ View full report in Codecov by Sentry. |
p2p/server/server.go
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| ctx, cancel := context.WithCancel(ctx) | ||
| eg.Go(func() error { | ||
| <-ctx.Done() | ||
| // deadlineAdjuster.Close() is safe to call multiple times | ||
| req.stream.Close() | ||
| return nil | ||
| }) | ||
| eg.Go(func() error { | ||
| defer cancel() |
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I think this does the same without needing to spawn a dedicated go routine?
| ctx, cancel := context.WithCancel(ctx) | |
| eg.Go(func() error { | |
| <-ctx.Done() | |
| // deadlineAdjuster.Close() is safe to call multiple times | |
| req.stream.Close() | |
| return nil | |
| }) | |
| eg.Go(func() error { | |
| defer cancel() | |
| eg.Go(func() error { | |
| defer req.stream.Close() |
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No, there's a critical difference: if the context is canceled while the handler is still executing (e.g. the server is stopped in a test by means of canceling the context passed to its Run method), a blocking I/O operation may still hang and the handler will never exit, also this defer will never be executed. In my implementation, the stream is closed immediately after the context is canceled, which may happen not only due defer cancel(), but also b/c the context passed to Run is canceled; closing the stream interrupts any current blocking operations
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bors merge |
## Motivation When a P2P Server request is canceled or a server is stopped while serving a request, some code paths that involve blocking I/O calls may hang b/c the P2P stream is not closed upon cancellation of the context that was passed to `StreamRequest` / `Request` or `Run`. On top of that, the context which is passed to server handlers is not canceled when the server exits. This was split off #5769 where a P2P test was hanging when trying to stop the P2P servers.
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Pull request successfully merged into develop. Build succeeded: |
spacemesh-bors
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changed the title
Motivation
When a P2P Server request is canceled or a server is stopped while serving a request, some code paths that involve blocking I/O calls may hang b/c the P2P stream is not closed upon cancellation of the context that was passed to
StreamRequest/RequestorRun. On top of that, the context which is passed to server handlers is not canceled when the server exits.This was split off #5769 where a P2P test was hanging when trying to stop the P2P servers.
Description
Close P2P server streams upon context cancellation. Cancel handlers' context when the handler functions exit