pyln-testing: wait for listen port release before starting a node#9355
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ksedgwic wants to merge 1 commit into
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pyln-testing: wait for listen port release before starting a node#9355ksedgwic wants to merge 1 commit into
ksedgwic wants to merge 1 commit into
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A node's connectd is a separate process holding the listen socket, and on shutdown it exits on its own schedule after lightningd itself is gone -- under valgrind, its teardown can lag by tens of seconds. If a test restarts the node in that window, the new connectd fails with 'Address already in use', lightningd exits, and the test times out waiting for 'Server started with public key'. Seen in CI in test_emergencyrecoverpenaltytxn, where the port was still held 37 seconds after the old connectd began shutting down. The filesystem port locks don't cover this: they keep other workers from reserving the port, but the restarting node owns its reservation both times; nothing waits for the old connectd to actually release the socket. Before launching lightningd, bind-probe the node's port (with SO_REUSEADDR, matching connectd, so TIME_WAIT sockets don't count as in use) and only proceed once the bind succeeds. Fixes: ElementsProject#9354 Changelog-None
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Fixes #9354 : when a test restarts a node, the previous connectd --
slow to exit under valgrind -- can still hold the listen socket, so
the new connectd fails with 'Address already in use' and the test
times out waiting for 'Server started with public key'.
Before launching lightningd, bind-probe the node's port with
SO_REUSEADDR and wait until the bind succeeds.
Validated by holding a stopped node's port from the test process and
restarting: without this change that reproduces the CI failure
exactly (same BROKEN bind message and timeout); with it, start waits
out the holder and proceeds.
Changelog-None