Function ExampleRegistry_grouping

prometheus/registry_test.go:1267–1297

This example shows how to use multiple registries for registering and unregistering groups of metrics.

()

// This example shows how to use multiple registries for registering and
// unregistering groups of metrics.
func ExampleRegistry_grouping() {
	// Create a global registry.
	globalReg := prometheus.NewRegistry()

	// Spawn 10 workers, each of which will have their own group of metrics.
	for i := 0; i < 10; i++ {
		// Create a new registry for each worker, which acts as a group of
		// worker-specific metrics.
		workerReg := prometheus.NewRegistry()
		globalReg.Register(workerReg)

		go func(workerID int) {
			// Once the worker is done, it can unregister itself.
			defer globalReg.Unregister(workerReg)

			workTime := prometheus.NewCounter(prometheus.CounterOpts{
				Name: "worker_total_work_time_milliseconds",
				ConstLabels: prometheus.Labels{
					// Generate a label unique to this worker so its metric doesn't
					// collide with the metrics from other workers.
					"worker_id": strconv.Itoa(workerID),
				},
			})
			workerReg.MustRegister(workTime)

			start := time.Now()
			time.Sleep(time.Millisecond * time.Duration(rand.Intn(100)))
			workTime.Add(float64(time.Since(start).Milliseconds()))
		}(i)
	}
}

type customCollector struct {
	collectFunc func(ch chan<- prometheus.Metric)