A warm target's liveness probe called ModelLoader.Load, which blocked
until the model finished loading (while the warm preload loaded it
too). Tick waited for every probe, so all probing froze, and the probe
then ran HealthCheck on an expired context and tripped the target at
every startup.
The prober now takes a function that returns the running backend
without loading it. A target that is not loaded passes liveness; its
recovery is neither confirmed nor failed and it returns to healthy
after min_dwell, like a cold target. Tick no longer waits for probes:
each probe applies its own result and a target whose probe is running
is skipped.
Assisted-by: Claude:claude-opus-5-5
The request path called HasChains on every request, and with no chains
it scanned the config source each time: the loader's lock plus a copy
and sort of every config, forever, on every installation without
chains. Sync now keeps an atomic flag and HasChains reads only that.
A chain added since the last sync is still served because Plan syncs
on a miss; only in-request retry waits for the next tick (at most 1s).
Assisted-by: Claude:claude-opus-5-5
An admission rejection or a disabled target moves the request to the
next target through Attempt.Skip, which records no failure. A 4xx
response no longer counts as a success. Requests skip body recording
when no chain is configured, and stop it once the model is known not
to be a chain.
Assisted-by: Claude:claude-opus-5-5
Warm local targets are pinned in the watchdog and preloaded. Switches
and target health are exported as metrics, skipped attempts as traces.
Assisted-by: Claude:claude-opus-5-5
Idle targets get a liveness probe each interval, recovering targets an
inference probe. Cold local targets are never loaded to be probed.
Assisted-by: Claude:claude-opus-5-5
recomputeLocked only fired the event on an active-target change or on
entering degraded. When the active target itself recovered while every
target was down, the chain silently left degraded with no event, so
SSE/realtime consumers tracking chain.switched.state got stuck on
"degraded".
Assisted-by: Claude:claude-opus-5-5
errcheck flagged two side-effect-only m.Plan calls in tests, and unused
flagged close(), which Task 5's probe scheduler wires in.
Assisted-by: Claude:claude-opus-5-5
Health is tracked per target and the active target per chain. Fail-back
waits for recovery probes and a minimum time on the fallback.
Assisted-by: Claude:claude-opus-5-5
Ettore Di Giacinto