Close the observability gap between agent_hung (only tracked jobs by jobs.pid)
and orphaned pytest subprocesses the orchestrator launches itself
(merge_gate.retest_branch / coverage_gate.measure_coverage). On a timeout-kill of
the agent (-9, ORCH-109) the grand-child pytest reparents onto tini and keeps
running for days, starving CPU and failing merge-gate re-test — with no alert.
Strictly inside the observer (watchdog/** + the watchdog compose service):
- watchdog/collectors/proc.py: stdlib-only /proc scan (under pid: host),
read-only, never-raise -> []; pure parsers split from I/O (tested on a fake
/proc tree). Never reads /proc/<pid>/environ.
- watchdog/signals.py: pure proc_signals builder, per-entity
("proc_blocking", pid), active iff age_s > proc_age_s; actionable RU detail.
- watchdog/core.py: opt-in tick block (gated on proc_enabled -> zero overhead /
byte-for-byte when off) + RECOVERY synthesis for a vanished process through the
existing decide()/AlertState (no new anti-spam logic).
- watchdog/config.py: WATCHDOG_PROC_{ENABLED(false),AGE_MIN(60),PATTERNS(pytest),
COOLDOWN_S(1800)}; default threshold > max(merge_retest_timeout_s=600,
coverage_run_timeout_s=900) so a legit in-flight run never crosses it.
- docker-compose.yml: pid: host on orchestrator-watchdog ONLY (read-only privilege).
Anti-false-positive and no overlap with agent_hung are by construction (cmdline
scope + age threshold), not fragile cross-namespace PID matching.
Canon synced: WATCHDOG_PROC_* in .env.watchdog.example <-> .env.example block;
documented in LITE_SETUP.md and docs/architecture/README.md (architect). src/**,
/metrics, schema_version, STAGE_TRANSITIONS, QG_CHECKS, check_*, machine-verdict
and the DB schema are untouched; deploy rebuilds only the sidecar, prod
orchestrator is not restarted (NFR-3).
Tests: tests/watchdog/test_proc_blocking_signal.py (TC-01..TC-06),
test_proc_collector.py (/proc parsing), test_tick_proc_blocking_integration.py
(TC-07), plus pid: host and proc-config assertions. Full pytest tests/ green (1930).
Refs: ORCH-111
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Add the `watchdog/` package (thin Python-3.12 stdlib-only daemon) and the
`orchestrator-watchdog` compose service — the brain half of the domain-0
observability pair. F1a (ORCH-099) exposes GET /metrics raw signal; F1b reads it,
augments with host / container / dependency probes, runs each signal through a
generalised pure decision function (decide(signal_active, prev, now, cooldown),
a strict superset of disk_watchdog.decide_action) with per-signal in-memory
dedup/throttle/recovery, and alerts over its OWN independent Telegram channel.
Key properties (ADR-001):
- Observer separated from observed: separate container; /metrics not answering is
itself the master `orch_down` alarm (debounced K ticks — no flap on a hiccup).
- Strictly read-only: docker.sock GET-only + mounted :ro (double guard), host
paths :ro, no DB/disk writes, no process control — self-hosting-safe.
- never-raise on three levels (per-source/per-tick/per-send) + WATCHDOG_ENABLED
kill-switch (disabled -> inert idle-loop, not exit).
- Disk anti-duplicate (D6): disk_watchdog (ORCH-063) stays sole owner of the 85%
alert; sidecar carries orch_down + an opt-in 97% ceiling (default off).
- NO import from src/** (C-1); src/**, STAGE_TRANSITIONS, QG_CHECKS, check_*, DB
schema — untouched. env_file optional so a missing .env.watchdog never breaks
`docker compose up` for the prod orchestrator.
Tests: tests/watchdog/ (TC-01…TC-13) + full tests/ regression green (TC-14).
Docs: CHANGELOG, .env.example canon (WATCHDOG_*); architecture README + adr-0033
authored at the architecture stage.
Refs: ORCH-100
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
