Function fetchWithRetries

src/util/fetch/index.ts:626–684

(
  url: RequestInfo,
  options: FetchOptions = {},
  timeout: number,
  maxRetries?: number,
)

}

export async function fetchWithRetries(
  url: RequestInfo,
  options: FetchOptions = {},
  timeout: number,
  maxRetries?: number,
): Promise<Response> {
  const contextMaxRetries = getFetchRetryContextMaxRetries();
  maxRetries = Math.max(0, maxRetries ?? contextMaxRetries ?? 4);

  let lastErrorMessage: string | undefined;
  const backoff = getEnvInt('PROMPTFOO_REQUEST_BACKOFF_MS', 5000);

  for (let i = 0; i <= maxRetries; i++) {
    let response;
    try {
      // Disable transient retries in fetchWithProxy to avoid double-retrying
      response = await fetchWithTimeout(
        url,
        { ...options, disableTransientRetries: true },
        timeout,
      );

      if (getEnvBool('PROMPTFOO_RETRY_5XX') && response.status >= 500 && response.status < 600) {
        throw new Error(`Internal Server Error: ${response.status} ${response.statusText}`);
      }

      if (response && isRateLimited(response)) {
        await handleRateLimitedResponse(response, url, i, maxRetries);
        continue;
      }

      return response;
    } catch (error) {
      // Don't retry on abort - propagate immediately
      if (error instanceof Error && error.name === 'AbortError') {
        throw error;
      }

      // Structured rate-limit errors are already final (quota fail-fast or
      // retries exhausted) and carry retry-after / reset metadata. Don't
      // swallow them in the generic retry path.
      if (error instanceof HttpRateLimitError) {
        throw error;
      }

      const errorMessage = formatFetchErrorMessage(error);

      logger.debug(
        `Request to ${urlForLog(url)} failed (attempt #${i + 1}), retrying: ${errorMessage}`,
      );
      if (i < maxRetries) {
        const waitTime = Math.pow(2, i) * (backoff + 1000 * Math.random());
        await sleep(waitTime);
      }
      lastErrorMessage = errorMessage;
    }
  }
  throw new Error(`Request failed after ${maxRetries} retries: ${lastErrorMessage}`);