Sessions 5-7a: 955 tests, deployment ready

src/services/rateLimiter.js

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+/**
+ * Token bucket rate limiter, per upstream key.
+ *
+ * Each upstream (ESPN, Pinnacle, DK, etc.) gets its own bucket so a runaway
+ * caller on one source doesn't starve the others. Buckets refill on demand,
+ * so we don't pay for setInterval timers.
+ *
+ * Usage:
+ *   const limiter = require('./rateLimiter');
+ *   await limiter.take('espn', 1);   // throws if the wait would exceed maxWaitMs
+ */
+
+const DEFAULT_LIMIT = { capacity: 10, refillPerSec: 5 };
+
+// Tunable per source. Numbers chosen to stay well under each upstream's
+// observed rate limits.
+const LIMITS = Object.freeze({
+  espn:        { capacity: 30, refillPerSec: 10 },
+  pinnacle:    { capacity: 10, refillPerSec: 3 },
+  draftkings:  { capacity: 10, refillPerSec: 2 },
+  fanduel:     { capacity: 10, refillPerSec: 2 },
+  betmgm:      { capacity: 10, refillPerSec: 2 },
+  caesars:     { capacity: 10, refillPerSec: 2 },
+  prizepicks:  { capacity: 10, refillPerSec: 2 },
+  covers:      { capacity: 5,  refillPerSec: 1 },
+  rotowire:    { capacity: 5,  refillPerSec: 1 },
+  weather:     { capacity: 20, refillPerSec: 5 },
+  injuries:    { capacity: 20, refillPerSec: 5 },
+  'nba-stats': { capacity: 8,  refillPerSec: 1 },  // stats.nba.com is strict
+  pybaseball:  { capacity: 4,  refillPerSec: 0.5 }, // Statcast tolerates roughly 1 req / 2s
+});
+
+const buckets = new Map();
+
+function getBucket(key) {
+  let b = buckets.get(key);
+  if (!b) {
+    const cfg = LIMITS[key] || DEFAULT_LIMIT;
+    b = {
+      tokens: cfg.capacity,
+      capacity: cfg.capacity,
+      refillPerSec: cfg.refillPerSec,
+      lastRefillMs: Date.now(),
+    };
+    buckets.set(key, b);
+  }
+  return b;
+}
+
+function refill(b) {
+  const now = Date.now();
+  const elapsedSec = (now - b.lastRefillMs) / 1000;
+  if (elapsedSec <= 0) return;
+  b.tokens = Math.min(b.capacity, b.tokens + elapsedSec * b.refillPerSec);
+  b.lastRefillMs = now;
+}
+
+/**
+ * Wait for `cost` tokens on the named bucket. Resolves once tokens are
+ * consumed. Rejects if the projected wait exceeds maxWaitMs (default 5s).
+ */
+async function take(key, cost = 1, maxWaitMs = 5_000) {
+  const b = getBucket(key);
+  while (true) {
+    refill(b);
+    if (b.tokens >= cost) {
+      b.tokens -= cost;
+      return;
+    }
+    const needed = cost - b.tokens;
+    const waitMs = Math.ceil((needed / b.refillPerSec) * 1000);
+    if (waitMs > maxWaitMs) {
+      const err = new Error(`rate limit wait exceeded for ${key}`);
+      err.code = 'RATE_LIMIT_TIMEOUT';
+      err.retryAfterMs = waitMs;
+      throw err;
+    }
+    await new Promise((r) => setTimeout(r, Math.min(waitMs, 250)));
+  }
+}
+
+function snapshot() {
+  const out = {};
+  for (const [k, b] of buckets.entries()) {
+    refill(b);
+    out[k] = { tokens: Math.floor(b.tokens), capacity: b.capacity, refillPerSec: b.refillPerSec };
+  }
+  return out;
+}
+
+module.exports = { take, snapshot, LIMITS };