Metrics

By default, controller-runtime builds a global prometheus registry and publishes a collection of performance metrics for each controller.

Publishing Additional Metrics

If you wish to publish additional metrics from your controllers, this can be easily achieved by using the global registry from controller-runtime/pkg/metrics.

One way to achieve this is to declare your collectors as global variables and then register them using init().

For example:

import (
    "github.com/prometheus/client_golang/prometheus"
    "sigs.k8s.io/controller-runtime/pkg/metrics"
)

var (
    goobers = prometheus.NewCounter(
        prometheus.CounterOpts{
            Name: "goobers_total",
            Help: "Number of goobers proccessed",
        },
    )
    gooberFailures = prometheus.NewCounter(
        prometheus.CounterOpts{
            Name: "goober_failures_total",
            Help: "Number of failed goobers",
        },
    )
)

func init() {
    // Register custom metrics with the global prometheus registry
    metrics.Registry.MustRegister(goobers, gooberFailures)
}

You may then record metrics to those collectors from any part of your reconcile loop, and those metrics will be available for prometheus or other openmetrics systems to scrape.