This section describes how to create a metric or a group of metrics to extend the monitoring metrics that Che is exposing.

There are two major modules for metrics:

  • che-core-metrics-core — contains core metrics module

  • che-core-api-metrics — contains metrics that are dependent on core Che components, such as workspace or user managers

Procedure

  • Create a class that extends the MeterBinder class. This allows to register the created metric in the overridden bindTo(MeterRegistry registry) method.

    The following is an example of a metric that has a function that supplies the value for it:

    Example metric
    public class UserMeterBinder implements MeterBinder {

  private final UserManager userManager;

  @Inject
  public UserMeterBinder(UserManager userManager) {
    this.userManager = userManager;
  }

  @Override
  public void bindTo(MeterRegistry registry) {
    Gauge.builder("che.user.total", this::count)
        .description("Total amount of users")
        .register(registry);
  }

  private double count() {
    try {
      return userManager.getTotalCount();
    } catch (ServerException e) {
      return Double.NaN;
    }
  }

    Alternatively, the metric can be stored with a reference and updated manually in some other place in the code.

Additional resources