A fresh SnmpEngine() was created on every poll_device() call and never
closed. pysnmp opens a UDP transport socket per engine and doesn't release
it on GC, so each scheduler tick (default 60s, per device) leaked a file
descriptor. Over hours of polling the process hit its fd ceiling and the
listening socket could no longer accept connections — OSError: [Errno 24]
Too many open files on socket.accept(), locking up the app.
Wrap the engine in try/finally and release its transport socket via a new
_close_engine() helper that probes both pysnmp API shapes (6.2.x lextudio
camelCase, canonical 7.x snake_case); all close paths are best-effort so a
failed close never breaks the poll loop. Regression tests cover both shapes
and the never-raises contract.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The SNMP plugin ships in the image but logged "pysnmp not installed — SNMP
polling disabled" on every poll, so polling never worked. Two coupled defects:
1. The Dockerfile installed only `.[ansible]`, so the `snmp` extra (pysnmp)
was never bundled even though the plugin is first-party and shipped.
2. poller.py used the synchronous pysnmp HLAPI (`next(getCmd(...))`), which
pysnmp-lextudio 6.x removed — it's asyncio-only now — so even with the dep
present, polling would have thrown and silently returned nothing. The 5.x
line that still has the sync API isn't safe on the image's Python 3.13.
Fix:
- Dockerfile: install `.[ansible,snmp]`.
- poller.py: `poll_device_sync` → `async def poll_device` on the asyncio HLAPI,
with a dual-version import (pysnmp 7.x `pysnmp.hlapi.v3arch.asyncio`/`get_cmd`
+ async `UdpTransportTarget.create`; pysnmp-lextudio 6.2.x
`pysnmp.hlapi.asyncio`/`getCmd` + direct `UdpTransportTarget`) so a dependency
bump can't silently re-break it.
- scheduler.py: await poll_device directly; drop the run_in_executor wrapper
and the now-unused asyncio import.
- Add tests/plugins/snmp/test_poller.py covering the version→mpModel mapping,
that the poller is a coroutine, and the graceful no-pysnmp path.
Note: CI confirms import/load and the no-pysnmp path, but has no SNMP target —
live polling against real devices is verified after deploy.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016Jg27rgypiW2efULXJDtMC
bvandeusen