Added examples

counter_example_test.go

@@ -0,0 +1,41 @@
+package metrics_test
+
+import (
+	"fmt"
+	"github.com/VictoriaMetrics/metrics"
+)
+
+func ExampleCounter() {
+	// Define a counter in global scope.
+	var c = metrics.NewCounter(`metric_total{label1="value1", label2="value2"}`)
+
+	// Increment the counter when needed.
+	for i := 0; i < 10; i++ {
+		c.Inc()
+	}
+	n := c.Get()
+	fmt.Println(n)
+
+	// Output:
+	// 10
+}
+
+func ExampleCounter_vec() {
+	for i := 0; i < 3; i++ {
+		// Dynamically construct metric name and pass it to GetOrCreateCounter.
+		name := fmt.Sprintf(`metric_total{label1=%q, label2="%d"}`, "value1", i)
+		metrics.GetOrCreateCounter(name).Add(i + 1)
+	}
+
+	// Read counter values.
+	for i := 0; i < 3; i++ {
+		name := fmt.Sprintf(`metric_total{label1=%q, label2="%d"}`, "value1", i)
+		n := metrics.GetOrCreateCounter(name).Get()
+		fmt.Println(n)
+	}
+
+	// Output:
+	// 1
+	// 2
+	// 3
+}

gauge_example_test.go

@@ -0,0 +1,18 @@
+package metrics_test
+
+import (
+	"fmt"
+	"runtime"
+
+	"github.com/VictoriaMetrics/metrics"
+)
+
+func ExampleGauge() {
+	// Define a gauge exporting the number of goroutines.
+	var g = metrics.NewGauge(`goroutines_count`, func() float64 {
+		return float64(runtime.NumGoroutine())
+	})
+
+	// Obtain gauge value.
+	fmt.Println(g.Get())
+}

metrics_example_test.go

@@ -0,0 +1,14 @@
+package metrics_test
+
+import (
+	"net/http"
+
+	"github.com/VictoriaMetrics/metrics"
+)
+
+func ExampleWritePrometheus() {
+	// Export all the registered metrics in Prometheus format at `/metrics` http path.
+	http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {
+		metrics.WritePrometheus(w, true)
+	})
+}

summary_example_test.go

@@ -0,0 +1,31 @@
+package metrics_test
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/VictoriaMetrics/metrics"
+)
+
+func ExampleSummary() {
+	// Define a summary in global scope.
+	var s = metrics.NewSummary(`request_duration_seconds{path="/foo/bar"}`)
+
+	// Update the summary with the duration of processRequest call.
+	startTime := time.Now()
+	processRequest()
+	s.UpdateDuration(startTime)
+}
+
+func ExampleSummary_vec() {
+	for i := 0; i < 3; i++ {
+		// Dynamically construct metric name and pass it to GetOrCreateSummary.
+		name := fmt.Sprintf(`response_size_bytes{path=%q}`, "/foo/bar")
+		response := processRequest()
+		metrics.GetOrCreateSummary(name).Update(float64(len(response)))
+	}
+}
+
+func processRequest() string {
+	return "foobar"
+}