Initial commit

src/util/Retry.ts

@@ -0,0 +1,63 @@
+import type { ConfigRetryPolicy } from '../interface/Config'
+import Util from './Utils'
+
+type NumericPolicy = {
+  maxAttempts: number
+  baseDelay: number
+  maxDelay: number
+  multiplier: number
+  jitter: number
+}
+
+export type Retryable<T> = () => Promise<T>
+
+export class Retry {
+  private policy: NumericPolicy
+
+  constructor(policy?: ConfigRetryPolicy) {
+    const def: NumericPolicy = {
+      maxAttempts: 3,
+      baseDelay: 1000,
+      maxDelay: 30000,
+      multiplier: 2,
+      jitter: 0.2
+    }
+  const merged: ConfigRetryPolicy = { ...(policy || {}) }
+    // normalize string durations
+    const util = new Util()
+    const parse = (v: number | string) => {
+      if (typeof v === 'number') return v
+      try { return util.stringToMs(String(v)) } catch { return def.baseDelay }
+    }
+    this.policy = {
+      maxAttempts: (merged.maxAttempts as number) ?? def.maxAttempts,
+      baseDelay: parse(merged.baseDelay ?? def.baseDelay),
+      maxDelay: parse(merged.maxDelay ?? def.maxDelay),
+      multiplier: (merged.multiplier as number) ?? def.multiplier,
+      jitter: (merged.jitter as number) ?? def.jitter
+    }
+  }
+
+  async run<T>(fn: Retryable<T>, isRetryable?: (e: unknown) => boolean): Promise<T> {
+    let attempt = 0
+    let delay = this.policy.baseDelay
+    let lastErr: unknown
+  while (attempt < this.policy.maxAttempts) {
+      try {
+        return await fn()
+      } catch (e) {
+        lastErr = e
+        attempt += 1
+        const retry = isRetryable ? isRetryable(e) : true
+        if (!retry || attempt >= this.policy.maxAttempts) break
+        const jitter = 1 + (Math.random() * 2 - 1) * this.policy.jitter
+        const sleep = Math.min(this.policy.maxDelay, Math.max(0, Math.floor(delay * jitter)))
+        await new Promise((r) => setTimeout(r, sleep))
+        delay = Math.min(this.policy.maxDelay, Math.floor(delay * (this.policy.multiplier || 2)))
+      }
+    }
+    throw lastErr instanceof Error ? lastErr : new Error(String(lastErr))
+  }
+}
+
+export default Retry