Add request duration metric

Author: Laurie T. Malau

components/public-api-server/pkg/proxy/conn.go

@@ -10,6 +10,7 @@ import (
 	gitpod "github.com/gitpod-io/gitpod/gitpod-protocol"
 	"github.com/grpc-ecosystem/go-grpc-middleware/logging/logrus/ctxlogrus"
 	"net/url"
+	"time"
 )
 
 type ServerConnectionPool interface {
@@ -26,6 +27,10 @@ type NoConnectionPool struct {
 func (p *NoConnectionPool) Get(ctx context.Context, token string) (gitpod.APIInterface, error) {
 	logger := ctxlogrus.Extract(ctx)
 
+	start := time.Now()
+	defer func() {
+		reportConnectionDuration(time.Since(start))
+	}()
 	server, err := gitpod.ConnectToServer(p.ServerAPI.String(), gitpod.ConnectToServerOpts{
 		Context: ctx,
 		Token:   token,

components/public-api-server/pkg/proxy/prometheusmetrics.go

@@ -0,0 +1,24 @@
+// Copyright (c) 2022 Gitpod GmbH. All rights reserved.
+// Licensed under the GNU Affero General Public License (AGPL).
+// See License-AGPL.txt in the project root for license information.
+
+package proxy
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"time"
+)
+
+func reportConnectionDuration(d time.Duration) {
+	proxyConnectionCreateDurationSeconds.Observe(d.Seconds())
+}
+
+var proxyConnectionCreateDurationSeconds = prometheus.NewHistogram(prometheus.HistogramOpts{
+	Namespace: "gitpod",
+	Name:      "public_api_proxy_connection_create_duration_seconds",
+	Help:      "Histogram of connection time in seconds",
+})
+
+func RegisterMetrics(registry *prometheus.Registry) {
+	registry.MustRegister(proxyConnectionCreateDurationSeconds)
+}

components/public-api-server/pkg/proxy/prometheusmetrics_test.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2022 Gitpod GmbH. All rights reserved.
+// Licensed under the GNU Affero General Public License (AGPL).
+// See License-AGPL.txt in the project root for license information.
+
+package proxy
+
+import (
+	"context"
+	"github.com/gitpod-io/gitpod/common-go/baseserver"
+	v1 "github.com/gitpod-io/gitpod/public-api/v1"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/stretchr/testify/assert"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/metadata"
+	"testing"
+)
+
+func TestConnectionCreationWasTracked(t *testing.T) {
+	// Set up server
+	srv := baseserver.NewForTests(t)
+	baseserver.StartServerForTests(t, srv)
+
+	// Set up Prometheus registry
+	registry := prometheus.NewRegistry()
+	registry.MustRegister(proxyConnectionCreateDurationSeconds)
+
+	// Set up Workspace client
+	ctx := metadata.AppendToOutgoingContext(context.Background(), "authorization", "some-token")
+	conn, _ := grpc.Dial(srv.GRPCAddress(), grpc.WithTransportCredentials(insecure.NewCredentials()))
+	client := v1.NewWorkspacesServiceClient(conn)
+
+	// Call GetWorkspace
+	client.GetWorkspace(ctx, &v1.GetWorkspaceRequest{
+		WorkspaceId: "some-ID",
+	})
+
+	count, err := testutil.GatherAndCount(registry)
+	assert.NoError(t, err)
+	assert.Equal(t, 1, count)
+}

components/public-api-server/pkg/server/integration_test.go

@@ -8,6 +8,7 @@ import (
 	"context"
 	"github.com/gitpod-io/gitpod/common-go/baseserver"
 	v1 "github.com/gitpod-io/gitpod/public-api/v1"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
@@ -21,11 +22,12 @@ import (
 func TestPublicAPIServer_v1_WorkspaceService(t *testing.T) {
 	ctx := metadata.AppendToOutgoingContext(context.Background(), "authorization", "some-token")
 	srv := baseserver.NewForTests(t)
+	registry := prometheus.NewRegistry()
 
 	gitpodAPI, err := url.Parse("wss://main.preview.gitpod-dev.com/api/v1")
 	require.NoError(t, err)
 
-	require.NoError(t, register(srv, Config{GitpodAPI: gitpodAPI}))
+	require.NoError(t, register(srv, Config{GitpodAPI: gitpodAPI}, registry))
 	baseserver.StartServerForTests(t, srv)
 
 	conn, err := grpc.Dial(srv.GRPCAddress(), grpc.WithTransportCredentials(insecure.NewCredentials()))
@@ -67,11 +69,12 @@ func TestPublicAPIServer_v1_WorkspaceService(t *testing.T) {
 func TestPublicAPIServer_v1_PrebuildService(t *testing.T) {
 	ctx := context.Background()
 	srv := baseserver.NewForTests(t)
+	registry := prometheus.NewRegistry()
 
 	gitpodAPI, err := url.Parse("wss://main.preview.gitpod-dev.com/api/v1")
 	require.NoError(t, err)
 
-	require.NoError(t, register(srv, Config{GitpodAPI: gitpodAPI}))
+	require.NoError(t, register(srv, Config{GitpodAPI: gitpodAPI}, registry))
 
 	baseserver.StartServerForTests(t, srv)
 

components/public-api-server/pkg/server/server.go

@@ -12,21 +12,25 @@ import (
 	"github.com/gitpod-io/gitpod/public-api-server/pkg/apiv1"
 	"github.com/gitpod-io/gitpod/public-api-server/pkg/proxy"
 	v1 "github.com/gitpod-io/gitpod/public-api/v1"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/sirupsen/logrus"
 	"net/http"
 )
 
 func Start(logger *logrus.Entry, cfg Config) error {
+	registry := prometheus.NewRegistry()
+
 	srv, err := baseserver.New("public_api_server",
 		baseserver.WithLogger(logger),
 		baseserver.WithHTTPPort(cfg.HTTPPort),
 		baseserver.WithGRPCPort(cfg.GRPCPort),
+		baseserver.WithMetricsRegistry(registry),
 	)
 	if err != nil {
 		return fmt.Errorf("failed to initialize public api server: %w", err)
 	}
 
-	if registerErr := register(srv, cfg); registerErr != nil {
+	if registerErr := register(srv, cfg, registry); registerErr != nil {
 		return fmt.Errorf("failed to register services: %w", registerErr)
 	}
 
@@ -37,7 +41,9 @@ func Start(logger *logrus.Entry, cfg Config) error {
 	return nil
 }
 
-func register(srv *baseserver.Server, cfg Config) error {
+func register(srv *baseserver.Server, cfg Config, registry *prometheus.Registry) error {
+	proxy.RegisterMetrics(registry)
+
 	logger := log.New()
 	m := middleware.NewLoggingMiddleware(logger)
 	srv.HTTPMux().Handle("/", m(http.HandlerFunc(HelloWorldHandler)))