如何在Loopback 4中跟踪请求id？

Question

我试图在我的REST API中使用Loopback 4跟踪每个HTTP请求，以便使用log4js在控制器中记录它们，就像这样。

[2020-05-05T19:21:52.191] [INFO] [request-id:47e9a486-1243-1c07-3ac0-0acc9cce2c0e] user.controller.ts - starting request validation
[2020-05-05T19:21:52.191] [INFO] [request-id:1dc81e45-093a-8009-42d2-e545c3a10c9d] user.controller.ts - starting request validation
[2020-05-05T19:21:53.126] [INFO] [request-id:47e9a486-1243-1c07-3ac0-0acc9cce2c0e] user.controller.ts - request validation success
[2020-05-05T19:21:53.145] [ERROR] [request-id:1dc81e45-093a-8009-42d2-e545c3a10c9d] user.controller.ts - request validation failed

这个... 大问题 这里是 [request-id:UUID] 部分，因为Node.js有时会混淆日志，我无法识别其中哪些属于同一个请求。我已经找到了一些针对Express应用的解决方案，但我无法找到一种方法让它与Loopback 4和log4js一起工作。

• https:/itnext.iorequest-id-tracing-in-node-js-applications-c517c7dab62d。
• https:/solidgeargroup.comenexpress-logging-global-unique-request-identificator-nodejs。
• 在node.js中通过ID跟踪请求流。

解决方法可能涉及到Sequence处理程序的使用，但我还没弄明白怎么做。注入Request对象的一些提示。https:/github.comstronglooploopback-nextissues1881#issuecomment-431384142。

Answer 1

我们使用winston logger做的，它是作为一个日志服务注入到我们的sequence.ts中的。下面是sequence.ts的代码。

export class MySequence implements SequenceHandler {
  constructor(
    @inject(SequenceActions.FIND_ROUTE) protected findRoute: FindRoute,
    @inject(SequenceActions.PARSE_PARAMS) protected parseParams: ParseParams,
    @inject(SequenceActions.INVOKE_METHOD) protected invoke: InvokeMethod,
    @inject(SequenceActions.SEND) public send: Send,
    @inject(SequenceActions.REJECT) public reject: Reject,
    @inject(LOGGER.LOGGER_INJECT) public logger: ILogger,
    @inject(HelmetSecurityBindings.HELMET_SECURITY_ACTION)
    protected helmetAction: HelmetAction,
    @inject(RateLimitSecurityBindings.RATELIMIT_SECURITY_ACTION)
    protected rateLimitAction: RateLimitAction,
    @inject(AlivioBindings.i18n)
    protected i18n: i18nAPI,
  ) {}

  async handle(context: RequestContext) {
    const requestTime = Date.now();
    try {
      const {request, response} = context;
      this.logger.info(
        `Request ${request.method} ${
          request.url
        } started at ${requestTime.toString()}.
        Request Details
        Referer = ${request.headers.referer}
        User-Agent = ${request.headers['user-agent']}
        Remote Address = ${request.connection.remoteAddress}
        Remote Address (Proxy) = ${request.headers['x-forwarded-for']}`,
      );
      const route = this.findRoute(request);
      const args = await this.parseParams(request, route);

      await this.rateLimitAction(request, response);
      await this.helmetAction(request, response);

      request.body = args[args.length - 1];
      const result = await this.invoke(route, args);
      this.send(response, result);
    } catch (err) {
      this.logger.error(
        `Request ${context.request.method} ${
          context.request.url
        } errored out. Error :: ${JSON.stringify(err)} ${err}`,
      );

      this.reject(context, error);
    } finally {
      this.logger.info(
        `Request ${context.request.method} ${
          context.request.url
        } Completed in ${Date.now() - requestTime}ms`,
      );
    }
  }
}

你可以在这里使用任何记录器作为提供者。你可以在log4js上创建一个封装提供者，然后像上面那样做。希望这对你有帮助。如果你也想看提供者的代码，请告诉我。我也会分享的。