The operator, reviewing SNMP on #5214: "this system looks incomplete like
there's something missing from it". The one device shown was plugin.yaml's
example (core-switch 192.168.1.1, community public), polled every minute;
devices could only be defined by editing YAML in the image; a failed poll was
logged at DEBUG and stored nowhere, so the page said "waiting for the next
poll" forever; v3 ran as v2c; counters showed as lifetime totals.
- Devices are rows (snmp_devices, migration snmp_001): address, port,
v1/v2c community or a v3 user with auth/priv protocols and keys (secrets
encrypted), presets plus custom readings, an optional host binding, and
the newest poll's outcome. The YAML device list and its example are gone.
- The SNMP page adds, edits and deletes them (admin, audited, with
get_audit_entities so the audit log names and links a device). Readings
come from presets (system uptime, interface traffic by number, UPS-MIB,
Linux net-snmp) and custom "OID name [unit]" lines.
- One GET per device with every OID, devices polled at once. The outcome is
written to the row in words ("No reply from … within 5 s. Check the address
and port, that SNMP is on, and the community"), with readings it lacks.
v1's whole-request error drops that OID and asks again. SNMPv3 signs in
with USM (MD5/SHA-1/SHA-2, DES/3DES/AES).
- Test asks the unsaved form's device for its name, description, uptime and
interfaces by number. It is an admin's explicit action; every page reads
only stored rows (System 178's ruling).
- Each reading has a unit; a counter is stored as a per-second rate (bytes as
bit/s), a reset or wrap skipped. The page, widget and host panel say values
in units and why a device is silent; the device page draws a chart per
reading on a dated axis.
Tests: readings and presets, the form and its secrets, v3 checks, rates,
the poller against a stand-in pysnmp (one GET, v1 retry, timeout wording,
USM), the pages, and an integration test of the poll writing outcomes and
rates on Postgres.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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
bvandeusenandClaude Opus 5.5