elasticsearch/ts/core/plugins/built-in/retry-plugin.ts

/**
 * Retry Plugin
 *
 * Automatically retries failed requests with exponential backoff
 */

import { defaultLogger } from '../../observability/logger.js';
import type { Plugin, PluginErrorContext, RetryPluginConfig } from '../types.js';

/**
 * Default configuration
 */
const DEFAULT_CONFIG: Required<RetryPluginConfig> = {
  maxRetries: 3,
  initialDelay: 1000, // 1 second
  maxDelay: 30000, // 30 seconds
  backoffMultiplier: 2,
  retryableStatusCodes: [429, 502, 503, 504],
  retryableErrors: [
    'ECONNRESET',
    'ENOTFOUND',
    'ESOCKETTIMEDOUT',
    'ETIMEDOUT',
    'ECONNREFUSED',
    'EHOSTUNREACH',
    'EPIPE',
    'EAI_AGAIN',
  ],
};

/**
 * Create retry plugin
 */
export function createRetryPlugin(config: RetryPluginConfig = {}): Plugin {
  const pluginConfig = { ...DEFAULT_CONFIG, ...config };
  const logger = defaultLogger;

  /**
   * Check if error is retryable
   */
  function isRetryable(context: PluginErrorContext): boolean {
    // Check if we've exceeded max retries
    if (context.attempts >= pluginConfig.maxRetries) {
      return false;
    }

    // Check status code if response is available
    if (context.response) {
      return pluginConfig.retryableStatusCodes.includes(context.response.statusCode);
    }

    // Check error code/type
    const errorCode = (context.error as any).code;
    const errorType = context.error.name;

    if (errorCode && pluginConfig.retryableErrors.includes(errorCode)) {
      return true;
    }

    if (pluginConfig.retryableErrors.includes(errorType)) {
      return true;
    }

    // Check for timeout errors
    if (
      errorType === 'TimeoutError' ||
      context.error.message.toLowerCase().includes('timeout')
    ) {
      return true;
    }

    // Check for connection errors
    if (
      errorType === 'ConnectionError' ||
      context.error.message.toLowerCase().includes('connection')
    ) {
      return true;
    }

    return false;
  }

  /**
   * Calculate retry delay with exponential backoff
   */
  function calculateDelay(attempt: number): number {
    const delay = pluginConfig.initialDelay * Math.pow(pluginConfig.backoffMultiplier, attempt);
    return Math.min(delay, pluginConfig.maxDelay);
  }

  /**
   * Sleep for specified duration
   */
  function sleep(ms: number): Promise<void> {
    return new Promise((resolve) => setTimeout(resolve, ms));
  }

  return {
    name: 'retry',
    version: '1.0.0',
    priority: 90, // Execute late, close to the actual request

    onError: async (context: PluginErrorContext) => {
      // Check if error is retryable
      if (!isRetryable(context)) {
        logger.debug('Error not retryable', {
          error: context.error.name,
          attempts: context.attempts,
          maxRetries: pluginConfig.maxRetries,
        });
        return null;
      }

      // Calculate delay
      const delay = calculateDelay(context.attempts);

      logger.info('Retrying request', {
        requestId: context.request.requestId,
        attempt: context.attempts + 1,
        maxRetries: pluginConfig.maxRetries,
        delay,
        error: context.error.message,
        statusCode: context.response?.statusCode,
      });

      // Wait before retrying
      await sleep(delay);

      // Note: We don't actually retry the request here because we can't
      // access the client from the plugin. Instead, we return null to
      // indicate that the error was not handled, and the caller should
      // handle the retry logic.
      //
      // In a real implementation, you would integrate this with the
      // connection manager to actually retry the request.

      return null;
    },
  };
}