fix(db): bound the Lambda connection pool + DB circuit breaker#38
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The Lambda DB path handed PrismaPg a connection string with ?connection_limit=1, which @prisma/adapter-pg ignores, so each warm execution environment's pool used the pg default max:10. Under a burst of signups (or a pre-token cache-miss storm) the Lambda fleet could exhaust RDS max_connections and make Postgres reject connections from every client. Fix: construct an explicit pg.Pool({max:1, connectionTimeoutMillis, idleTimeoutMillis}) and pass it to PrismaPg so per-Lambda connection count is deterministic (env knobs LAMBDA_DATABASE_POOL_MAX / LAMBDA_DATABASE_CONNECT_TIMEOUT_MS); add a LAMBDA_DATABASE_PROXY_HOST override to route through an RDS Proxy when provisioned; add a per-environment circuit breaker (withLambdaDbBreaker over DatabaseCircuitBreaker) wired into pre-token (loadFromRds) and post-confirmation (provisioning transaction) so a saturated DB fails fast instead of being retried; and emit a pre-token cache_miss event for a miss-rate metric.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
…ening Cuts 0.10.8 carrying the Lambda DB pool cap (max:1), RDS Proxy host override, and the Lambda circuit breaker from this PR. (0.10.7 was the generic entity-feed release.) Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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What & why
The Lambda DB path passed
PrismaPga connection string with?connection_limit=1, which@prisma/adapter-pgignores — so each warm execution environment's pool used thepgdefaultmax: 10. Under a burst of signups (or apre-tokencache-miss storm) the Lambda fleet could exhaust RDSmax_connectionsand make Postgres reject connections from every client — a global outage, not just failed signups.Changes
lambda-prisma: construct an explicitpg.Pool({ max: 1, connectionTimeoutMillis, idleTimeoutMillis })and pass it toPrismaPg, so per-Lambda connection count is deterministic (= concurrency, not concurrency × 10). Env-configurable:LAMBDA_DATABASE_POOL_MAX(default 1),LAMBDA_DATABASE_CONNECT_TIMEOUT_MS(default 2000).LAMBDA_DATABASE_PROXY_HOSToverride so handlers route through an RDS Proxy endpoint when one is provisioned (falls back to the direct instance — default deployment unchanged).withLambdaDbBreaker, over the existingDatabaseCircuitBreaker) wired intopre-token(loadFromRds) andpost-confirmation(provisioning transaction) so a saturated DB fails fast instead of being retried into the incident.pre-token: emit acache_missevent so a miss-rate metric can be derived.Tests
test/unit/lambda/lambda-prisma.test.ts— 7/7 passing (poolmax === 1, connect timeout, proxy-host override, client caching, breaker trip + fail-fast).tsctype-clean for the changed files (the lone pre-existingextensions.tsbuild error is unrelated — present onmainwithout this change).🤖 Generated with Claude Code