fix: make rate limiter fail closed when Redis is unreachable - #11
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Upstash Ratelimit's default 5s timeout resolves { success: true,
reason: 'timeout' } when Redis is unreachable, silently bypassing rate
limits. Add an explicit 1s timeout and have checkRateLimit translate the
timeout response (and any thrown error) into a deny, so limits can't be
bypassed by inducing Redis latency. Also drop the unused globalLimit.
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Summary
The Upstash rate limiter failed open: on its default 5s timeout it resolves
{ success: true, reason: 'timeout' }, so a Redis outage or induced latency let requests bypasssaveLimit/shareLimitentirely. This change makes the limiter fail closed, the correct default for an abuse-prevention control.Changes
timeout: 1000on the limiters (was defaulting to 5s).checkRateLimitnow denies on Upstash'stimeoutresponse and on any thrownerror, so limits cannot be bypassed by inducing Redis latency.
globalLimitexport.Trade-off
During a full Redis outage, save/share return
429rather than passing through. Impact is bounded to the outage window.Testing
Added
__tests__/rate-limit.test.ts(timeout, error, allow, deny). Full suite passing: 12 suites, 65 tests. Route handlers unchanged — the{ success, retryAfter }contract is preserved.