Add prometheus stats to server http handlers

Signed-off-by: Ying Li <ying.li@docker.com>

server/server.go

@@ -9,13 +9,13 @@ import (
 	"github.com/Sirupsen/logrus"
 	"github.com/docker/distribution/health"
 	"github.com/docker/distribution/registry/auth"
+	"github.com/docker/notary/server/handlers"
 	"github.com/docker/notary/tuf/data"
 	"github.com/docker/notary/tuf/signed"
-	"github.com/gorilla/mux"
-	"golang.org/x/net/context"
-
-	"github.com/docker/notary/server/handlers"
 	"github.com/docker/notary/utils"
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus"
+	"golang.org/x/net/context"
 )
 
 func init() {
@@ -26,6 +26,14 @@ func init() {
 	)
 }
 
+func prometheusOpts(operation string) prometheus.SummaryOpts {
+	return prometheus.SummaryOpts{
+		Namespace:   "notary_server",
+		Subsystem:   "http",
+		ConstLabels: prometheus.Labels{"operation": operation},
+	}
+}
+
 // Run sets up and starts a TLS server that can be cancelled using the
 // given configuration. The context it is passed is the context it should
 // use directly for the TLS server, and generate children off for requests
@@ -57,24 +65,10 @@ func Run(ctx context.Context, addr string, tlsConfig *tls.Config, trust signed.C
 			return err
 		}
 	}
-	hand := utils.RootHandlerFactory(ac, ctx, trust)
 
-	r := mux.NewRouter()
-	r.Methods("GET").Path("/v2/").Handler(hand(handlers.MainHandler))
-	r.Methods("POST").Path("/v2/{imageName:.*}/_trust/tuf/").Handler(hand(handlers.AtomicUpdateHandler, "push", "pull"))
-	r.Methods("GET").Path("/v2/{imageName:.*}/_trust/tuf/{tufRole:(root|targets|snapshot)}.json").Handler(hand(handlers.GetHandler, "pull"))
-	r.Methods("GET").Path("/v2/{imageName:.*}/_trust/tuf/timestamp.json").Handler(hand(handlers.GetTimestampHandler, "pull"))
-	r.Methods("GET").Path("/v2/{imageName:.*}/_trust/tuf/timestamp.key").Handler(hand(handlers.GetTimestampKeyHandler, "push", "pull"))
-	r.Methods("DELETE").Path("/v2/{imageName:.*}/_trust/tuf/").Handler(hand(handlers.DeleteHandler, "push", "pull"))
-	r.Methods("GET").Path("/_notary_server/health").Handler(hand(
-		func(ctx context.Context, w http.ResponseWriter, r *http.Request) error {
-			health.StatusHandler(w, r)
-			return nil
-		}))
-	r.Methods("GET", "POST", "PUT", "HEAD", "DELETE").Path("/{other:.*}").Handler(hand(utils.NotFoundHandler))
 	svr := http.Server{
 		Addr:    addr,
-		Handler: r,
+		Handler: RootHandler(ac, ctx, trust),
 	}
 
 	logrus.Info("Starting on ", addr)
@@ -83,3 +77,41 @@ func Run(ctx context.Context, addr string, tlsConfig *tls.Config, trust signed.C
 
 	return err
 }
+
+// RootHandler returns the handler that routes all the paths from / for the
+// server.
+func RootHandler(ac auth.AccessController, ctx context.Context, trust signed.CryptoService) http.Handler {
+	hand := utils.RootHandlerFactory(ac, ctx, trust)
+
+	r := mux.NewRouter()
+	r.Methods("GET").Path("/v2/").Handler(hand(handlers.MainHandler))
+	r.Methods("POST").Path("/v2/{imageName:.*}/_trust/tuf/").Handler(
+		prometheus.InstrumentHandlerWithOpts(
+			prometheusOpts("UpdateTuf"),
+			hand(handlers.AtomicUpdateHandler, "push", "pull")))
+	r.Methods("GET").Path("/v2/{imageName:.*}/_trust/tuf/{tufRole:(root|targets|snapshot)}.json").Handler(
+		prometheus.InstrumentHandlerWithOpts(
+			prometheusOpts("GetRole"),
+			hand(handlers.GetHandler, "pull")))
+	r.Methods("GET").Path("/v2/{imageName:.*}/_trust/tuf/timestamp.json").Handler(
+		prometheus.InstrumentHandlerWithOpts(
+			prometheusOpts("GetTimestamp"),
+			hand(handlers.GetTimestampHandler, "pull")))
+	r.Methods("GET").Path("/v2/{imageName:.*}/_trust/tuf/timestamp.key").Handler(
+		prometheus.InstrumentHandlerWithOpts(
+			prometheusOpts("GetTimestampKey"),
+			hand(handlers.GetTimestampKeyHandler, "push", "pull")))
+	r.Methods("DELETE").Path("/v2/{imageName:.*}/_trust/tuf/").Handler(
+		prometheus.InstrumentHandlerWithOpts(
+			prometheusOpts("DeleteTuf"),
+			hand(handlers.DeleteHandler, "push", "pull")))
+	r.Methods("GET").Path("/_notary_server/health").Handler(hand(
+		func(ctx context.Context, w http.ResponseWriter, r *http.Request) error {
+			health.StatusHandler(w, r)
+			return nil
+		}))
+	r.Methods("GET").Path("/_notary_server/metrics").Handler(prometheus.Handler())
+	r.Methods("GET", "POST", "PUT", "HEAD", "DELETE").Path("/{other:.*}").Handler(hand(utils.NotFoundHandler))
+
+	return r
+}

server/server_test.go

@@ -2,11 +2,14 @@ package server
 
 import (
 	"net"
+	"net/http"
+	"net/http/httptest"
 	"strings"
 	"testing"
 
 	_ "github.com/docker/distribution/registry/auth/silly"
 	"github.com/docker/notary/tuf/signed"
+	"github.com/stretchr/testify/assert"
 	"golang.org/x/net/context"
 )
 
@@ -43,3 +46,13 @@ func TestRunReservedPort(t *testing.T) {
 		t.Fatalf("Received unexpected err: %s", err.Error())
 	}
 }
+
+func TestMetricsEndpoint(t *testing.T) {
+	handler := RootHandler(nil, context.Background(), signed.NewEd25519())
+	ts := httptest.NewServer(handler)
+	defer ts.Close()
+
+	res, err := http.Get(ts.URL + "/_notary_server/metrics")
+	assert.NoError(t, err)
+	assert.Equal(t, http.StatusOK, res.StatusCode)
+}