Function ExampleCounterVec

prometheus/examples_test.go:132–174

()

}

func ExampleCounterVec() {
	httpReqs := prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Name: "http_requests_total",
			Help: "How many HTTP requests processed, partitioned by status code and HTTP method.",
		},
		[]string{"code", "method"},
	)
	prometheus.MustRegister(httpReqs)

	httpReqs.WithLabelValues("404", "POST").Add(42)

	// If you have to access the same set of labels very frequently, it
	// might be good to retrieve the metric only once and keep a handle to
	// it. But beware of deletion of that metric, see below!
	m := httpReqs.WithLabelValues("200", "GET")
	for i := 0; i < 1000000; i++ {
		m.Inc()
	}
	// Delete a metric from the vector. If you have previously kept a handle
	// to that metric (as above), future updates via that handle will go
	// unseen (even if you re-create a metric with the same label set
	// later).
	httpReqs.DeleteLabelValues("200", "GET")
	// Same thing with the more verbose Labels syntax.
	httpReqs.Delete(prometheus.Labels{"method": "GET", "code": "200"})

	// Just for demonstration, let's check the state of the counter vector
	// by registering it with a custom registry and then let it collect the
	// metrics.
	reg := prometheus.NewRegistry()
	reg.MustRegister(httpReqs)

	metricFamilies, err := reg.Gather()
	if err != nil || len(metricFamilies) != 1 {
		panic("unexpected behavior of custom test registry")
	}

	fmt.Println(toNormalizedJSON(sanitizeMetricFamily(metricFamilies[0])))

	// Output:
	// {"name":"http_requests_total","help":"How many HTTP requests processed, partitioned by status code and HTTP method.","type":"COUNTER","metric":[{"label":[{"name":"code","value":"404"},{"name":"method","value":"POST"}],"counter":{"value":42,"createdTimestamp":"1970-01-01T00:00:10Z"}}]}
}

func ExampleRegister() {
	// Imagine you have a worker pool and want to count the tasks completed.