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[READ-ONLY] Mirror of https://github.com/openstatusHQ/openstatus. 🫖 Status page with uptime monitoring & API monitoring as code 🫖 openstatus.dev
bun drizzle-orm monitoring monitoring-as-code nextjs observability on-call open-source shadcn-ui status-page statuspage synthetic-monitoring tinybird turso uptime uptime-checker uptime-monitor
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3.2 kB · 112 lines
TypeScript
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113// redis-free half of the limiter: importable from modules that must not// evaluate the upstash client (it throws without credentials in dev)
export interface RateLimitTier { name: string; // part of the redis key, must be stable window: number; // in seconds limit: number; // max requests per window}
export interface TieredRateLimitResult { success: boolean; limit: number; remaining: number; reset: number; // timestamp when the window resets tier: RateLimitTier; // the tier that blocked, or the one closest to its limit}
/** * Shared tiers for the public /play tools. The burst tier stops hammering, the * sustained tier stops automation that paces itself just under the burst limit. */export const PLAY_RATE_LIMIT_TIERS: RateLimitTier[] = [ { name: "burst", window: 60, limit: 3 }, { name: "sustained", window: 3600, limit: 10 },];
/** Index of the tier with the least headroom left, so headers report the real cap. */export function tightestTierIndex( tiers: RateLimitTier[], counts: number[],): number { let tightest = 0; for (let i = 1; i < tiers.length; i++) { if (tiers[i].limit - counts[i] < tiers[tightest].limit - counts[tightest]) { tightest = i; } } return tightest;}
/** * Decode the flat reply of RATELIMIT_TIERS_SCRIPT: * [blocked (1-based, 0 = admitted), ...counts, ...ttls] */export function parseTieredResult( tiers: RateLimitTier[], reply: number[], now: number,): TieredRateLimitResult { const counts = reply.slice(1, 1 + tiers.length); const ttls = reply.slice(1 + tiers.length, 1 + tiers.length * 2);
// TTL replies -1 (no expiry) and -2 (no key); fall back to a full window const resetOf = (i: number) => now + (ttls[i] > 0 ? ttls[i] * 1000 : tiers[i].window * 1000);
const blocked = reply[0]; if (blocked > 0) { const i = blocked - 1; return { success: false, limit: tiers[i].limit, remaining: 0, reset: resetOf(i), tier: tiers[i], }; }
const i = tightestTierIndex(tiers, counts); return { success: true, limit: tiers[i].limit, remaining: Math.max(0, tiers[i].limit - counts[i]), reset: resetOf(i), tier: tiers[i], };}
function formatWindow(seconds: number): string { if (seconds === 60) return "minute"; if (seconds === 3600) return "hour"; if (seconds === 86400) return "day"; return `${seconds} seconds`;}
export function rateLimitMessage(tier: RateLimitTier): string { return `You have exceeded the rate limit of ${tier.limit} requests per ${formatWindow(tier.window)}`;}
export function tieredRateLimitHeaders(result: { limit: number; remaining: number; reset: number; // ms epoch}): Record<string, string> { return { "X-RateLimit-Limit": result.limit.toString(), "X-RateLimit-Remaining": result.remaining.toString(), // the header convention is unix seconds, unlike the ms epoch we pass around "X-RateLimit-Reset": Math.ceil(result.reset / 1000).toString(), };}
export function retryAfterHeader(result: { reset: number;}): Record<string, string> { return { "Retry-After": Math.max( 1, Math.ceil((result.reset - Date.now()) / 1000), ).toString(), };}