Support for Metrics and Prometheus.

middlewares/metrics.go

@@ -0,0 +1,51 @@
+package middlewares
+
+import (
+	"github.com/go-kit/kit/metrics"
+	"net/http"
+	"strconv"
+	"time"
+)
+
+// Metrics is an Interface that must be satisfied by any system that
+// wants to expose and monitor metrics
+type Metrics interface {
+	getReqsCounter() metrics.Counter
+	getLatencyHistogram() metrics.Histogram
+	handler() http.Handler
+}
+
+// MetricsWrapper is a Negroni compatible Handler which relies on a
+// given Metrics implementation to expose and monitor Traefik metrics
+type MetricsWrapper struct {
+	Impl Metrics
+}
+
+// NewMetricsWrapper return a MetricsWrapper struct with
+// a given Metrics implementation e.g Prometheuss
+func NewMetricsWrapper(impl Metrics) *MetricsWrapper {
+	var metricsWrapper = MetricsWrapper{
+		Impl: impl,
+	}
+
+	return &metricsWrapper
+}
+
+func (m *MetricsWrapper) ServeHTTP(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
+	start := time.Now()
+	prw := &responseRecorder{rw, http.StatusOK}
+	next(prw, r)
+	labels := []string{"code", strconv.Itoa(prw.StatusCode()), "method", r.Method}
+	m.Impl.getReqsCounter().With(labels...).Add(1)
+	m.Impl.getLatencyHistogram().With(labels...).Observe(float64(time.Since(start).Nanoseconds()) / 1000000)
+}
+
+func (rw *responseRecorder) StatusCode() int {
+	return rw.statusCode
+}
+
+// Handler is the chance for the Metrics implementation
+// to expose its metrics on a server endpoint
+func (m *MetricsWrapper) Handler() http.Handler {
+	return m.Impl.handler()
+}

middlewares/prometheus.go

@@ -0,0 +1,65 @@
+package middlewares
+
+import (
+	"github.com/containous/traefik/types"
+	"github.com/go-kit/kit/metrics"
+	"github.com/go-kit/kit/metrics/prometheus"
+	stdprometheus "github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"net/http"
+)
+
+const (
+	reqsName    = "requests_total"
+	latencyName = "request_duration_milliseconds"
+)
+
+// Prometheus is an Implementation for Metrics that exposes prometheus metrics for the number of requests,
+// the latency and the response size, partitioned by status code and method.
+type Prometheus struct {
+	reqsCounter      metrics.Counter
+	latencyHistogram metrics.Histogram
+}
+
+func (p *Prometheus) getReqsCounter() metrics.Counter {
+	return p.reqsCounter
+}
+
+func (p *Prometheus) getLatencyHistogram() metrics.Histogram {
+	return p.latencyHistogram
+}
+
+// NewPrometheus returns a new prometheus Metrics implementation.
+func NewPrometheus(name string, config *types.Prometheus) *Prometheus {
+	var m Prometheus
+	m.reqsCounter = prometheus.NewCounterFrom(
+		stdprometheus.CounterOpts{
+			Name:        reqsName,
+			Help:        "How many HTTP requests processed, partitioned by status code and method.",
+			ConstLabels: stdprometheus.Labels{"service": name},
+		},
+		[]string{"code", "method"},
+	)
+
+	var buckets []float64
+	if config.Buckets != nil {
+		buckets = config.Buckets
+	} else {
+		buckets = []float64{100, 300, 1200, 5000}
+	}
+
+	m.latencyHistogram = prometheus.NewHistogramFrom(
+		stdprometheus.HistogramOpts{
+			Name:        latencyName,
+			Help:        "How long it took to process the request, partitioned by status code and method.",
+			ConstLabels: stdprometheus.Labels{"service": name},
+			Buckets:     buckets,
+		},
+		[]string{"code", "method"},
+	)
+	return &m
+}
+
+func (p *Prometheus) handler() http.Handler {
+	return promhttp.Handler()
+}

middlewares/prometheus_test.go

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+package middlewares
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/codegangsta/negroni"
+	"github.com/containous/traefik/types"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+func TestPrometheus(t *testing.T) {
+	recorder := httptest.NewRecorder()
+
+	n := negroni.New()
+	metricsMiddlewareBackend := NewMetricsWrapper(NewPrometheus("test", &types.Prometheus{}))
+	n.Use(metricsMiddlewareBackend)
+	r := http.NewServeMux()
+	r.Handle("/metrics", promhttp.Handler())
+	r.HandleFunc(`/ok`, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		fmt.Fprintln(w, "ok")
+	})
+	n.UseHandler(r)
+
+	req1, err := http.NewRequest("GET", "http://localhost:3000/ok", nil)
+	if err != nil {
+		t.Error(err)
+	}
+	req2, err := http.NewRequest("GET", "http://localhost:3000/metrics", nil)
+	if err != nil {
+		t.Error(err)
+	}
+
+	n.ServeHTTP(recorder, req1)
+	n.ServeHTTP(recorder, req2)
+	body := recorder.Body.String()
+	if !strings.Contains(body, reqsName) {
+		t.Errorf("body does not contain request total entry '%s'", reqsName)
+	}
+	if !strings.Contains(body, latencyName) {
+		t.Errorf("body does not contain request duration entry '%s'", reqsName)
+	}
+}