srt: auto-restart listener on transient UDP errors#5712
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JohanG-LAS wants to merge 1 commit intobluenviron:mainfrom
Open
srt: auto-restart listener on transient UDP errors#5712JohanG-LAS wants to merge 1 commit intobluenviron:mainfrom
JohanG-LAS wants to merge 1 commit intobluenviron:mainfrom
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The MediaMTX SRT server would permanently shut down whenever the underlying gosrt listener returned any non-deadline error from its ReadFrom loop (e.g. a transient `read udp: network is unreachable` caused by an Azure Accelerated Networking VF flap or any other short-lived UDP socket fault). gosrt marks the listener as done on such errors and Accept2() returns the error; MediaMTX then logged it and broke out of its server loop, leaving SRT unavailable until the process was restarted manually. Treat any non-ErrListenerClosed listener failure as recoverable: close the dead listener, retry srt.Listen with bounded exponential backoff plus jitter, and re-spawn the listener goroutine on success. ErrListenerClosed (returned during graceful shutdown) and context cancellation continue to exit the loop cleanly. Existing live connections, the server goroutine, the connection map, the API, and metrics are untouched: only the accept side is recreated. A package-level srtListen indirection allows tests to substitute a fake listener; three new tests cover the restart-on-transient, no-restart-on-closed, and give-up-on-context-cancel paths. Made-with: Cursor
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #5712 +/- ##
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+ Coverage 62.08% 63.23% +1.14%
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Files 214 217 +3
Lines 17602 18280 +678
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+ Hits 10929 11560 +631
- Misses 5766 5783 +17
- Partials 907 937 +30 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Cloud providers are regularly doing VM live migrations, causing VM's to freeze during a couple of seconds. See Azure and Google
TCP transport protocols often handles these "outages" well, but UDP protocols can struggle.
The MediaMTX SRT server would permanently shut down whenever the underlying gosrt listener returned any non-deadline error from its ReadFrom loop (e.g. a transient
read udp: network is unreachable).gosrt marks the listener as done on such errors and Accept2() returns the error. MediaMTX then logged it and broke out of its server loop, leaving SRT unavailable until the process was restarted manually.
Fix
Treat any non-ErrListenerClosed listener failure as recoverable: close the dead listener, retry srt.Listen with bounded exponential backoff plus jitter, and re-spawn the listener goroutine on success. ErrListenerClosed (returned during graceful shutdown) and context cancellation continue to exit the loop cleanly. Existing live connections, the server goroutine, the connection map, the API, and metrics are untouched: only the accept side is recreated.
Test
A package-level srtListen indirection allows tests to substitute a fake listener; three new tests cover the restart-on-transient, no-restart-on-closed, and give-up-on-context-cancel paths.
Made-with: Cursor