Wire ipc_write_buffer through to TCP transport per-stream cap - #69962
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dwoz wants to merge 1 commit into
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Wire ipc_write_buffer through to TCP transport per-stream cap#69962dwoz wants to merge 1 commit into
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…ack#69930) The ipc_write_buffer master option was left in the config schema after the legacy salt.transport.ipc module was removed in 3008.x, but was no longer read by any code path -- so setting it in master.conf was a silent no-op. Without a per-stream cap, a slow/blocked event-bus subscriber lets Tornado's per-connection outbound IOStream write buffer grow without bound, driving RSS growth on masters under sustained event churn. Apply the configured value as ``max_write_buffer_size`` on the Tornado IOStream in: - PubServer.handle_stream (plaintext subscribers) - PubServer._validate_ssl_and_add_client (SSL-delayed subscribers) - SaltMessageServer.handle_stream (request/reply clients) The default (unset / 0) preserves the existing unlimited-buffer behavior; operators opt in by setting an explicit byte value.
twangboy
approved these changes
Aug 5, 2026
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Fixes #69930.
Summary
The
ipc_write_buffermaster option was left in the config schema after the legacysalt.transport.ipcmodule was removed in 3008.x, but was no longer read by any code path -- setting it inmaster.confwas a silent no-op. Without a per-stream cap, a slow/blocked event-bus subscriber lets Tornados per-connection outboundIOStream` write buffer grow without bound, driving RSS growth on masters under sustained event churn.Apply
opts["ipc_write_buffer"]asmax_write_buffer_sizeon the TornadoIOStreamin:PubServer.handle_stream(plaintext subscribers)PubServer._validate_ssl_and_add_client(SSL-delayed subscribers)SaltMessageServer.handle_stream(request/reply clients)The default (unset /
0) preserves the existing unlimited-buffer behavior; operators opt in by setting an explicit byte value.Test plan
tests/pytests/unit/transport/test_tcp.py-- new cases assert the cap is applied on bothSaltMessageServerandPubServerstreams and that the unset/zero path leaves the stream untouched (5 new tests, all 47 in file pass).