feat: replace Werkzeug dev server with waitress for high-concurrency adapter#896
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AdamRajfer merged 3 commits intomainfrom Apr 8, 2026
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…adapter Werkzeug's `run_simple(threaded=True)` creates an unbounded thread per request with a socket backlog of 5, causing "connection reset by peer" errors at scale (11k+ concurrent connections). Replace with waitress, a production WSGI server that uses a fixed thread pool (default 2048) with proper connection queuing (default 16k connection limit). Also raises the file descriptor limit (RLIMIT_NOFILE) to 65536 in the adapter subprocess to prevent fd exhaustion under high concurrency. Configurable via env vars: - ADAPTER_SERVER_THREADS (default: 2048) - ADAPTER_SERVER_CONNECTION_LIMIT (default: 16384) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Signed-off-by: Alex Gronskiy <agronskiy@nvidia.com>
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AdamRajfer
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Signed-off-by: Adam Rajfer <arajfer@nvidia.com>
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…ainer errors Fixes two issues introduced in #896: - select.select() breaks with fds > 1023 after raising RLIMIT_NOFILE - localhost may resolve to ::1 in IPv6-disabled containers (EADDRNOTAVAIL) Signed-off-by: Alex Gronskiy <agronskiy@nvidia.com>
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Fixes two issues from #896: - **`filedescriptor out of range in select()`**: `select.select()` can't handle fds > 1023. After raising RLIMIT_NOFILE to 65536, this is easily hit. `asyncore_use_poll=True` switches to `select.poll()` which has no fd limit. - **`EADDRNOTAVAIL` in containers**: `localhost` resolves to `::1` in IPv6-disabled environments. `ipv6=False` forces IPv4-only binding. Reproduced the select() issue in a core-evals container (`terminal-bench:2026-02-09T10-38-9216d4e3-amd64`): default soft=1024, hard=524288; after raising and opening 1100 sockets, `select.select()` fails exactly as reported. ## Test plan - [x] 21/21 adapter server unit tests pass Signed-off-by: Alex Gronskiy <agronskiy@nvidia.com>
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Summary
run_simple(threaded=True)with waitress, a production WSGI server with a fixed thread pool and proper connection queuingRLIMIT_NOFILE) to 65536 in the adapter subprocessADAPTER_SERVER_THREADS(default 2048) andADAPTER_SERVER_CONNECTION_LIMIT(default 16384) for tunabilityContext
At 11k+ concurrent connections the Werkzeug dev server causes "connection reset by peer" errors due to:
Waitress uses a fixed thread pool with channel-based I/O, so excess connections queue rather than getting reset. Single-process architecture is preserved, keeping all
threading.Lock()in interceptors (caching, progress tracking, stats) valid.Test plan
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