service.ts

export interface Service {
  readonly id: string;

  /**
   * `run` is called once by the Service Runner to run the service.
   * The returned Promise resolves when the service stops, either because
   * {@link stop()} was called, or because the service
   * has completed its work. If the Promise rejects with an error, the
   * Service Runner will restart it with exponential backoff.
   */
  run(): Promise<void>;

  /**
   * Called to signal the service to stop. This is generally only used
   * in tests.
   */
  stop(): Promise<void>;
}

export interface ActivityBasedService extends Service {
  /**
   * Requests that service continue running if not already shutting down.
   * This is applicable to services whose life cycle is tied to external
   * activity and shutdown after a period of inactivity.
   *
   * @return `true` if the service will continue running for its
   *         configured keepalive interval, or `false` if it has
   *         already shut down or begun the shutdown process.
   */
  keepalive(): boolean;
}