func()

in app.go [359:388]

• 25 lines of code
• 5 McCabe index (conditional complexity)

func (a *theApp) listenMetrics(eg *errgroup.Group, config cfg.Metrics) *http.Server {
	server := newHTTPServer(a)
	eg.Go(func() error {
		l, err := net.Listen("tcp", config.Address)
		if err != nil {
			errortracking.CaptureErrWithStackTrace(err, errortracking.WithField("listener", "metrics"))
			return fmt.Errorf("failed to listen on addr %s: %w", config.Address, err)
		}

		if config.TLSConfig != nil {
			l = cryptotls.NewListener(l, config.TLSConfig)
		}

		monitoringOpts := []monitoring.Option{
			monitoring.WithBuildInformation(VERSION, ""),
			monitoring.WithListener(l),
			monitoring.WithServer(server),
		}

		err = monitoring.Start(monitoringOpts...)
		if err != nil && !errors.Is(err, http.ErrServerClosed) {
			errortracking.CaptureErrWithStackTrace(err, errortracking.WithField("listener", "metrics"))
			return err
		}

		return nil
	})

	return server
}