feat: retry parts (#3369)

packages/opencode/src/session/retry.ts

@@ -0,0 +1,57 @@
+import { MessageV2 } from "./message-v2"
+
+export namespace SessionRetry {
+  export const RETRY_INITIAL_DELAY = 2000
+  export const RETRY_BACKOFF_FACTOR = 2
+
+  export async function sleep(ms: number, signal: AbortSignal): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const timeout = setTimeout(resolve, ms)
+      signal.addEventListener(
+        "abort",
+        () => {
+          clearTimeout(timeout)
+          reject(new DOMException("Aborted", "AbortError"))
+        },
+        { once: true },
+      )
+    })
+  }
+
+  export function getRetryDelayInMs(error: MessageV2.APIError, attempt: number): number {
+    const base = RETRY_INITIAL_DELAY * Math.pow(RETRY_BACKOFF_FACTOR, attempt - 1)
+    const headers = error.data.responseHeaders
+    if (!headers) return base
+
+    const retryAfterMs = headers["retry-after-ms"]
+    if (retryAfterMs) {
+      const parsed = Number.parseFloat(retryAfterMs)
+      const normalized = normalizeDelay({ base, candidate: parsed })
+      if (normalized != null) return normalized
+    }
+
+    const retryAfter = headers["retry-after"]
+    if (!retryAfter) return base
+
+    const seconds = Number.parseFloat(retryAfter)
+    if (!Number.isNaN(seconds)) {
+      const normalized = normalizeDelay({ base, candidate: seconds * 1000 })
+      if (normalized != null) return normalized
+      return base
+    }
+
+    const dateMs = Date.parse(retryAfter) - Date.now()
+    const normalized = normalizeDelay({ base, candidate: dateMs })
+    if (normalized != null) return normalized
+
+    return base
+  }
+
+  function normalizeDelay(input: { base: number; candidate: number }): number | undefined {
+    if (Number.isNaN(input.candidate)) return undefined
+    if (input.candidate < 0) return undefined
+    if (input.candidate < 60_000) return input.candidate
+    if (input.candidate < input.base) return input.candidate
+    return undefined
+  }
+}