fix: close writer and notify relay on target EOF in edge agent#77
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fix: close writer and notify relay on target EOF in edge agent#77
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read_from_tcp_and_send() broke on empty read (remote EOF) without
closing the asyncio StreamWriter or removing the entry from
active_connections. Each SSH/VNC session that ends naturally leaked one
file descriptor. On a default systemd soft limit of 1024 fds the process
eventually exhausts its budget; asyncio.open_connection() then fails
with [Errno 16] Device or resource busy (Python 3.13 happy-eyeballs
translates EMFILE as EBUSY).
Fix: wrap the read loop in try/finally that
- calls writer.close() to release the fd
- pops from active_connections so stale entries don't accumulate
- sends EtRConnectionResetMessage to notify the relay the target
closed its side (guarded against a closed websocket)
elikoga
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to Thymis-io/thymis
that referenced
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Mar 27, 2026
Pins to Thymis-io/http-network-relay#77 which fixes the fd leak in edge_agent read_from_tcp_and_send(). Revert the pin to main once that PR is merged.
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Problem
read_from_tcp_and_send()exited on empty read (remote EOF) without closing theasyncio.StreamWriteror removing the entry fromactive_connections. Every SSH/VNC session that ends naturally leaked one file descriptor.On the default systemd soft limit of 1024 fds the agent exhausts its budget;
asyncio.open_connection()then fails with[Errno 16] Device or resource busy(Python 3.13 happy-eyeballs translatesEMFILEasEBUSY). The agent stops proxying all connections until restarted.Observed in production on a HomePi4 running thymis-agent continuously — terminal/SSH relay broke after accumulated sessions hit the fd ceiling.
Fix
Wrap the read loop in
try/finallythat:writer.close()to release the fdactive_connectionsso stale entries don't accumulateEtRConnectionResetMessageto notify the relay the target closed its side (guarded against a closed websocket)