feat(serverless): report fitness failure to host before force-exit

[deanq]

What

Worker side of SLS-380. On a startup fitness-check failure, the worker sends one best-effort report to the host (over the existing ping channel) just before force-exiting, so the host can emit a queryable worker.fitness_failed event. Follow-up to SLS-379 (#536).

Details

• _report_unhealthy(check, reason) in rp_fitness.py: single GET to RUNPOD_WEBHOOK_PING (same URL/creds as the heartbeat) with status=unhealthy, check=<check name>, reason=<ErrorType: message>[:256], runpod_version. Bounded 2s timeout, no retries.
• Wired into the failure branch of run_fitness_checks, before the force-exit. The report is fully swallowed and the call site is wrapped, so it can never delay or block _terminate_unhealthy(1) (the SLS-379 exit guarantee).
• Off-platform no-op: skipped when RUNPOD_WEBHOOK_PING or RUNPOD_AI_API_KEY is unset (local/test).

Stacking

Based on the SLS-379 branch (deanq/sls-379-fitness-force-kill, PR #536) because the report only makes sense with the os._exit force-kill. Retarget to main once #536 merges.

Test plan

• make quality-check: 532 passed, coverage 94.18%.
• New tests: report posts correct check/reason; skipped without ping URL / without API key; truncates reason to 256; swallows HTTP errors; failure path reports before exit (and the SLS-379 subprocess test proves the process still dies).

Consumed by

The ai-api host PR that reads status=unhealthy and emits @sls.event:worker.fitness_failed. This PR degrades to a no-op if the host ignores the param.

Follow-ups (from final review, non-blocking)

• Worker report is unauthenticated at the host (inherits the ping endpoint's posture); dashboard-only scope avoids automated triggers.
• Optional: debug-log on report skip/success/failure for diagnosability.

SLS-380

[capy-ai]

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[Copilot]

Pull request overview

Adds a best-effort “fitness failure” report from the worker to the host right before the existing force-exit path, allowing the host to emit a queryable worker.fitness_failed event without weakening the SLS-379 hard-exit semantics.

Changes:

• Introduces _report_unhealthy(check, reason) to send a single GET over the existing ping channel with status=unhealthy, check, reason (truncated), and runpod_version.
• Wires the report into run_fitness_checks()’s failure path immediately before _terminate_unhealthy(1), swallowing all errors.
• Extends the existing force-kill regression test suite with new coverage for the report behavior and ordering.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
runpod/serverless/modules/rp_fitness.py	Adds _report_unhealthy and calls it on fitness-check failure before force-exit.
tests/test_serverless/test_modules/test_fitness/test_force_kill.py	Adds unit tests covering the unhealthy report behavior and “report before exit” ordering.

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