普罗米修斯客户端不返回自定义度量

我试图在Node.js应用程序中实现我自己的普罗米修斯度量,但我不明白为什么它不在 getMetrics() 方法如下所示:

import { Injectable } from '@nestjs/common';
import { collectDefaultMetrics, Counter, metric, Registry } from 'prom-client';

@Injectable()
export class PrometheusService {
  private register: Registry;
  private restRequestCounter: Counter;

  constructor() {
    this.register = new Registry();
    collectDefaultMetrics({ register: this.register });

    this.restRequestCounter = new Counter({
      name: 'incoming_rest_request_count',
      help: 'Number of all incoming http requests for this service'
    });
  }

  public incrementHttpRequestCount(): void {
    this.restRequestCounter.inc(1);
  }

  public getMetrics(): metric[] {
    return this.register.getMetricsAsJSON();
  }
}