vercel-flags-core: jitter ingest retries and batch-wait window, honor Retry-After#371
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vincent-derks wants to merge 1 commit intomainfrom
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vercel-flags-core: jitter ingest retries and batch-wait window, honor Retry-After#371vincent-derks wants to merge 1 commit intomainfrom
vincent-derks wants to merge 1 commit intomainfrom
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… Retry-After Replace the deterministic 100/200ms retry schedule with full-jitter exponential backoff, jitter MAX_BATCH_WAIT_MS by ±20% to desynchronize concurrent flushes, honor Retry-After (capped at 5s), and log when a flush exhausts all retries. Helpers extracted to utils/backoff.ts so they can be reused.
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Summary
The usage tracker's
/v1/ingestretry path used a deterministic 100/200ms schedule with no jitter, and the 5s batch-wait window was likewise unjittered. Concurrent processes that started at the same moment would all flush together and, when the server returned a non-2xx, retry in lockstep — amplifyingtransient pressure. This PR addresses that and adds basic observability on dropped batches.Changes
delay = random(0, base * 2^(attempt-1)), capped at 5s). Replaces the previousattempt * 100ms schedule.MAX_BATCH_WAIT_MSis now perturbed by ±20% per process so independent processes don't flush at the same wall-clock instant.Retry-Afteron non-2xx responses (delta-seconds and HTTP-date forms), capped at 5s so a misbehaving upstream can't keep the function alive.Test plan
utils/backoff.test.tscovering parsing edge cases,exponential ceiling,
Retry-Afterfloor + cap, custombaseMs/capMs,and the symmetric jitter bounds.
utils/usage-tracker.test.tsfor end-to-endwiring (
Retry-Afterflows into the retry loop, exhaustion log,no-exhaustion log on success).
pnpm --filter @vercel/flags-core test→ 438/438 pass.pnpm --filter @vercel/flags-core type-check→ clean.