Example #1
0
func (r *registry) giveMetric(m *dto.Metric) {
	m.Reset()
	select {
	case r.metricPool <- m:
	default:
	}
}
Example #2
0
func ExampleExpvarCollector() {
	expvarCollector := prometheus.NewExpvarCollector(map[string]*prometheus.Desc{
		"memstats": prometheus.NewDesc(
			"expvar_memstats",
			"All numeric memstats as one metric family. Not a good role-model, actually... ;-)",
			[]string{"type"}, nil,
		),
		"lone-int": prometheus.NewDesc(
			"expvar_lone_int",
			"Just an expvar int as an example.",
			nil, nil,
		),
		"http-request-map": prometheus.NewDesc(
			"expvar_http_request_total",
			"How many http requests processed, partitioned by status code and http method.",
			[]string{"code", "method"}, nil,
		),
	})
	prometheus.MustRegister(expvarCollector)

	// The Prometheus part is done here. But to show that this example is
	// doing anything, we have to manually export something via expvar.  In
	// real-life use-cases, some library would already have exported via
	// expvar what we want to re-export as Prometheus metrics.
	expvar.NewInt("lone-int").Set(42)
	expvarMap := expvar.NewMap("http-request-map")
	var (
		expvarMap1, expvarMap2                             expvar.Map
		expvarInt11, expvarInt12, expvarInt21, expvarInt22 expvar.Int
	)
	expvarMap1.Init()
	expvarMap2.Init()
	expvarInt11.Set(3)
	expvarInt12.Set(13)
	expvarInt21.Set(11)
	expvarInt22.Set(212)
	expvarMap1.Set("POST", &expvarInt11)
	expvarMap1.Set("GET", &expvarInt12)
	expvarMap2.Set("POST", &expvarInt21)
	expvarMap2.Set("GET", &expvarInt22)
	expvarMap.Set("404", &expvarMap1)
	expvarMap.Set("200", &expvarMap2)
	// Results in the following expvar map:
	// "http-request-count": {"200": {"POST": 11, "GET": 212}, "404": {"POST": 3, "GET": 13}}

	// Let's see what the scrape would yield, but exclude the memstats metrics.
	metricStrings := []string{}
	metric := dto.Metric{}
	metricChan := make(chan prometheus.Metric)
	go func() {
		expvarCollector.Collect(metricChan)
		close(metricChan)
	}()
	for m := range metricChan {
		if strings.Index(m.Desc().String(), "expvar_memstats") == -1 {
			metric.Reset()
			m.Write(&metric)
			metricStrings = append(metricStrings, metric.String())
		}
	}
	sort.Strings(metricStrings)
	for _, s := range metricStrings {
		fmt.Println(strings.TrimRight(s, " "))
	}
	// Output:
	// label:<name:"code" value:"200" > label:<name:"method" value:"GET" > untyped:<value:212 >
	// label:<name:"code" value:"200" > label:<name:"method" value:"POST" > untyped:<value:11 >
	// label:<name:"code" value:"404" > label:<name:"method" value:"GET" > untyped:<value:13 >
	// label:<name:"code" value:"404" > label:<name:"method" value:"POST" > untyped:<value:3 >
	// untyped:<value:42 >
}