Initial Commit

packages/api-stack/api/api-ws-broker-redis/src/reconnect/reconnect.ts

@@ -0,0 +1,27 @@
+import type { RedisReconnectStrategy } from "../options/options.js";
+
+/**
+ * Compute the next backoff delay in milliseconds for the configured
+ * exponential reconnect strategy. Capped at `maxDelayMs`. Pure function,
+ * trivially deterministic — the broker drives an external timer.
+ */
+export function nextReconnectDelayMs(
+    attempt: number,
+    strategy: RedisReconnectStrategy
+): number {
+    if (attempt < 0) return strategy.initialDelayMs;
+    const raw = strategy.initialDelayMs * strategy.multiplier ** attempt;
+    return Math.min(raw, strategy.maxDelayMs);
+}
+
+/**
+ * Decide whether the reconnect loop should give up. Once `attempt` reaches
+ * the configured maximum, the broker raises `WS_BROKER_REDIS.RECONNECT_FAILED`
+ * and surfaces `down` health.
+ */
+export function shouldGiveUp(
+    attempt: number,
+    strategy: RedisReconnectStrategy
+): boolean {
+    return attempt >= strategy.maxAttempts;
+}