Method constructor

src/monitoring.ts:373–390

(
    protected config: Config,
    statsSource?: MachineStatsSource,
    logFn?: (msg: string) => void,
  )

  protected firstSamplePromise: Promise<void>;

  constructor(
    protected config: Config,
    statsSource?: MachineStatsSource,
    logFn?: (msg: string) => void,
  ) {
    super();
    this.statsSource =
      statsSource ?? detectMachineStatsSource(config.getMachineStatsSource());
    const log = logFn ?? ((msg: string) => this.log.info(msg));
    log(`Machine stats source: ${this.statsSource.name}`);

    this.firstSamplePromise = this.sample();
    this.samplerHandle = setInterval(() => {
      this.sample();
    }, this.config.getCpuSampleIntervalMs());
    // Don't keep the event loop alive solely for this timer (test runners hang otherwise).
    this.samplerHandle.unref();
  }

  protected async sample(): Promise<void> {
    const { cpu, memory } = await this.statsSource.read();