feat: add Prometheus metrics with OTel sidecar

cloudbuild.yaml

@@ -1,39 +1,58 @@
 substitutions:
   _REGION: us-east1
   _SERVICE_NAME: speed-proxy
+  _MLAB_PROJECT: mlab-sandbox
   _ALLOWED_ORIGIN: https://speed.measurementlab.net
-  _TOKEN_EXCHANGE_URL: https://auth.mlab-sandbox.measurementlab.net/v0/token/integration
 
 steps:
-  # 1. Build the container image
+  # 1. Build the speed-proxy container image
   - name: "gcr.io/cloud-builders/docker"
     id: Build
+    waitFor: ['-']
     args: ["build", "-t", "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/${_SERVICE_NAME}:$BUILD_ID", "-t", "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/${_SERVICE_NAME}:latest", "."]
 
-  # 2. Push to Artifact Registry
+  # 2. Build the otel-collector sidecar image
+  - name: "gcr.io/cloud-builders/docker"
+    id: BuildOtel
+    waitFor: ['-']
+    args: ["build", "-t", "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/otel-collector:$BUILD_ID", "-t", "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/otel-collector:latest", "otel-collector"]
+
+  # 3. Push speed-proxy image to Artifact Registry
   - name: "gcr.io/cloud-builders/docker"
     id: Push
     args: ["push", "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/${_SERVICE_NAME}:${BUILD_ID}"]
     waitFor: ["Build"]
 
-  # 3. Deploy to Cloud Run
+  # 4. Push otel-collector image to Artifact Registry
+  - name: "gcr.io/cloud-builders/docker"
+    id: PushOtel
+    args: ["push", "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/otel-collector:${BUILD_ID}"]
+    waitFor: ["BuildOtel"]
+
+  # 5. Substitute placeholders in service.yaml and deploy
   - name: "gcr.io/google.com/cloudsdktool/cloud-sdk"
     id: Deploy
-    entrypoint: gcloud
-    args: [
-      "run", "deploy", "${_SERVICE_NAME}",
-      "--image", "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/${_SERVICE_NAME}:$BUILD_ID",
-      "--platform", "managed",
-      "--region", "${_REGION}",
-      "--allow-unauthenticated",
-      "--set-secrets=API_KEY=speed-proxy-api-key:latest",
-      "--set-env-vars=TOKEN_EXCHANGE_URL=${_TOKEN_EXCHANGE_URL},ALLOWED_ORIGIN=${_ALLOWED_ORIGIN}",
-      "--memory=256Mi",
-      "--cpu=1",
-      "--project=${PROJECT_ID}"
-    ]
-    waitFor: ["Push"]
+    entrypoint: bash
+    args:
+      - -c
+      - |
+        sed -e "s|OTEL_IMAGE_PLACEHOLDER|${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/otel-collector:${BUILD_ID}|g" \
+            -e "s|IMAGE_PLACEHOLDER|${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/${_SERVICE_NAME}:${BUILD_ID}|g" \
+            -e "s|MLAB_PROJECT_PLACEHOLDER|${_MLAB_PROJECT}|g" \
+            -e "s|ALLOWED_ORIGIN_PLACEHOLDER|${_ALLOWED_ORIGIN}|g" \
+            service.yaml > service-deploy.yaml
+        gcloud run services replace service-deploy.yaml \
+          --region=${_REGION} \
+          --project=${PROJECT_ID}
+        gcloud run services set-iam-policy ${_SERVICE_NAME} \
+          --region=${_REGION} \
+          --project=${PROJECT_ID} \
+          --quiet \
+          <(echo '{"bindings":[{"role":"roles/run.invoker","members":["allUsers"]}]}')
+    waitFor: ["Push", "PushOtel"]
 
 images:
   - "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/${_SERVICE_NAME}:$BUILD_ID"
   - "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/${_SERVICE_NAME}:latest"
+  - "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/otel-collector:$BUILD_ID"
+  - "${_REGION}-docker.pkg.dev/${PROJECT_ID}/m-lab/otel-collector:latest"

go.mod

@@ -2,9 +2,21 @@ module github.com/m-lab/speed-proxy
 
 go 1.25.5
 
-require github.com/m-lab/go v0.1.76
+require (
+	github.com/m-lab/go v0.1.76
+	github.com/prometheus/client_golang v1.7.1
+)
 
 require (
 	github.com/araddon/dateparse v0.0.0-20200409225146-d820a6159ab1 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.1.1 // indirect
+	github.com/golang/protobuf v1.4.2 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/common v0.10.0 // indirect
+	github.com/prometheus/procfs v0.1.3 // indirect
 	github.com/stretchr/testify v1.10.0 // indirect
+	golang.org/x/sys v0.0.0-20200615200032-f1bc736245b1 // indirect
+	google.golang.org/protobuf v1.23.0 // indirect
 )

go.sum

@@ -1,14 +1,118 @@
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+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
+google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
+google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
+google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE=
+google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
+google.golang.org/protobuf v1.23.0 h1:4MY060fB1DLGMB/7MBTLnwQUY6+F09GEiz6SsrNqyzM=
+google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
+gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.5/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

handler/handler.go

@@ -8,6 +8,10 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/m-lab/speed-proxy/metrics"
 )
 
 // Config contains the configuration for the token handler.
@@ -91,12 +95,20 @@ func (h *Handler) exchangeToken(ctx context.Context, apiKey string) (string, err
 	}
 	req.Header.Set("Content-Type", "application/json")
 
+	start := time.Now()
 	resp, err := h.config.HTTPClient.Do(req)
+	duration := time.Since(start).Seconds()
+
 	if err != nil {
+		metrics.UpstreamRequestDuration.WithLabelValues("error").Observe(duration)
+		metrics.UpstreamRequestsTotal.WithLabelValues("error").Inc()
 		return "", fmt.Errorf("failed to send request: %w", err)
 	}
 	defer resp.Body.Close()
 
+	metrics.UpstreamRequestDuration.WithLabelValues("success").Observe(duration)
+	metrics.UpstreamRequestsTotal.WithLabelValues(strconv.Itoa(resp.StatusCode)).Inc()
+
 	if resp.StatusCode != http.StatusOK {
 		body, _ := io.ReadAll(resp.Body)
 		return "", fmt.Errorf("token exchange failed with status %d: %s", resp.StatusCode, string(body))

main.go

@@ -11,8 +11,11 @@ import (
 	"time"
 
 	"github.com/m-lab/go/flagx"
+	"github.com/m-lab/go/prometheusx"
 	"github.com/m-lab/go/rtx"
 	"github.com/m-lab/speed-proxy/handler"
+	"github.com/m-lab/speed-proxy/metrics"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 var (
@@ -30,6 +33,8 @@ func main() {
 		log.Fatal("-api-key is required")
 	}
 
+	prometheusx.MustServeMetrics()
+
 	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 	defer stop()
 
@@ -41,8 +46,17 @@ func main() {
 		HTTPClient:       &http.Client{Timeout: 10 * time.Second},
 	})
 
+	// Wrap handler with promhttp instrumentation.
+	tokenHandler := promhttp.InstrumentHandlerDuration(
+		metrics.TokenRequestDuration,
+		promhttp.InstrumentHandlerCounter(
+			metrics.TokenRequestsTotal,
+			http.HandlerFunc(h.Token),
+		),
+	)
+
 	mux := http.NewServeMux()
-	mux.HandleFunc("/v0/token", h.Token)
+	mux.Handle("/v0/token", tokenHandler)
 	mux.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusOK)
 		w.Write([]byte("ok"))

metrics/metrics.go

@@ -0,0 +1,48 @@
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	// TokenRequestsTotal counts incoming token requests.
+	// Used with promhttp.InstrumentHandlerCounter.
+	TokenRequestsTotal = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "speedproxy_token_requests_total",
+			Help: "Total number of token requests.",
+		},
+		[]string{"code", "method"},
+	)
+
+	// TokenRequestDuration measures incoming token request latency.
+	// Used with promhttp.InstrumentHandlerDuration.
+	TokenRequestDuration = promauto.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name:    "speedproxy_token_request_duration_seconds",
+			Help:    "Duration of token requests.",
+			Buckets: prometheus.DefBuckets,
+		},
+		[]string{"code", "method"},
+	)
+
+	// UpstreamRequestsTotal counts upstream token exchange requests.
+	UpstreamRequestsTotal = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "speedproxy_upstream_requests_total",
+			Help: "Total number of upstream token exchange requests.",
+		},
+		[]string{"code"},
+	)
+
+	// UpstreamRequestDuration measures upstream token exchange latency.
+	UpstreamRequestDuration = promauto.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name:    "speedproxy_upstream_request_duration_seconds",
+			Help:    "Duration of upstream token exchange requests.",
+			Buckets: prometheus.DefBuckets,
+		},
+		[]string{"result"},
+	)
+)

metrics/metrics_test.go

@@ -0,0 +1,11 @@
+package metrics
+
+import (
+	"testing"
+
+	"github.com/m-lab/go/prometheusx/promtest"
+)
+
+func TestLintMetrics(t *testing.T) {
+	promtest.LintMetrics(t)
+}

otel-collector/Dockerfile

@@ -0,0 +1,2 @@
+FROM otel/opentelemetry-collector-contrib:latest
+COPY config.yaml /etc/otelcol-contrib/config.yaml