Add initial set of metrics for BBR

Author: rramkumar1

Diff for: cmd/body-based-routing/main.go

@@ -18,18 +18,26 @@ package main
 
 import (
 	"flag"
+	"net"
+	"net/http"
 	"os"
+	"strconv"
 
 	"github.com/go-logr/logr"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	uberzap "go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 	"google.golang.org/grpc"
 	healthPb "google.golang.org/grpc/health/grpc_health_v1"
+	"k8s.io/client-go/rest"
+	"k8s.io/component-base/metrics/legacyregistry"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/log/zap"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
+	"sigs.k8s.io/controller-runtime/pkg/metrics/filters"
 	"sigs.k8s.io/gateway-api-inference-extension/internal/runnable"
 	runserver "sigs.k8s.io/gateway-api-inference-extension/pkg/body-based-routing/server"
+	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/metrics"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/util/logging"
 )
 
@@ -42,6 +50,8 @@ var (
 		"grpcHealthPort",
 		9003,
 		"The port used for gRPC liveness and readiness probes")
+	metricsPort = flag.Int(
+		"metricsPort", 9090, "The metrics port")
 	logVerbosity = flag.Int("v", logging.DEFAULT, "number for the log level verbosity")
 
 	setupLog = ctrl.Log.WithName("setup")
@@ -95,6 +105,11 @@ func run() error {
 		return err
 	}
 
+	// Register metrics handler.
+	if err := registerMetricsHandler(mgr, *metricsPort, cfg); err != nil {
+		return err
+	}
+
 	// Start the manager. This blocks until a signal is received.
 	setupLog.Info("Manager starting")
 	if err := mgr.Start(ctx); err != nil {
@@ -135,3 +150,58 @@ func initLogging(opts *zap.Options) {
 	logger := zap.New(zap.UseFlagOptions(opts), zap.RawZapOpts(uberzap.AddCaller()))
 	ctrl.SetLogger(logger)
 }
+
+const metricsEndpoint = "/metrics"
+
+// registerMetricsHandler adds the metrics HTTP handler as a Runnable to the given manager.
+func registerMetricsHandler(mgr manager.Manager, port int, cfg *rest.Config) error {
+	metrics.Register()
+
+	// Init HTTP server.
+	h, err := metricsHandlerWithAuthenticationAndAuthorization(cfg)
+	if err != nil {
+		return err
+	}
+
+	mux := http.NewServeMux()
+	mux.Handle(metricsEndpoint, h)
+
+	srv := &http.Server{
+		Addr:    net.JoinHostPort("", strconv.Itoa(port)),
+		Handler: mux,
+	}
+
+	if err := mgr.Add(&manager.Server{
+		Name:   "metrics",
+		Server: srv,
+	}); err != nil {
+		setupLog.Error(err, "Failed to register metrics HTTP handler")
+		return err
+	}
+	return nil
+}
+
+func metricsHandlerWithAuthenticationAndAuthorization(cfg *rest.Config) (http.Handler, error) {
+	h := promhttp.HandlerFor(
+		legacyregistry.DefaultGatherer,
+		promhttp.HandlerOpts{},
+	)
+	httpClient, err := rest.HTTPClientFor(cfg)
+	if err != nil {
+		setupLog.Error(err, "Failed to create http client for metrics auth")
+		return nil, err
+	}
+
+	filter, err := filters.WithAuthenticationAndAuthorization(cfg, httpClient)
+	if err != nil {
+		setupLog.Error(err, "Failed to create metrics filter for auth")
+		return nil, err
+	}
+	metricsLogger := ctrl.Log.WithName("metrics").WithValues("path", metricsEndpoint)
+	metricsAuthHandler, err := filter(metricsLogger, h)
+	if err != nil {
+		setupLog.Error(err, "Failed to create metrics auth handler")
+		return nil, err
+	}
+	return metricsAuthHandler, nil
+}

Diff for: pkg/body-based-routing/handlers/request.go

@@ -24,6 +24,7 @@ import (
 	basepb "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
 	eppb "github.com/envoyproxy/go-control-plane/envoy/service/ext_proc/v3"
 	"sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/gateway-api-inference-extension/pkg/body-based-routing/metrics"
 	logutil "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/util/logging"
 )
 
@@ -38,6 +39,7 @@ func (s *Server) HandleRequestBody(ctx context.Context, body *eppb.HttpBody) (*e
 
 	modelVal, ok := data["model"]
 	if !ok {
+		metrics.RecordModelNotInBodyCounter()
 		logger.V(logutil.DEFAULT).Info("Request body does not contain model parameter")
 		return &eppb.ProcessingResponse{
 			Response: &eppb.ProcessingResponse_RequestBody{
@@ -48,6 +50,7 @@ func (s *Server) HandleRequestBody(ctx context.Context, body *eppb.HttpBody) (*e
 
 	modelStr, ok := modelVal.(string)
 	if !ok {
+		metrics.RecordModelNotParsedCounter()
 		logger.V(logutil.DEFAULT).Info("Model parameter value is not a string")
 		return &eppb.ProcessingResponse{
 			Response: &eppb.ProcessingResponse_RequestBody{
@@ -56,6 +59,7 @@ func (s *Server) HandleRequestBody(ctx context.Context, body *eppb.HttpBody) (*e
 		}, fmt.Errorf("the model parameter value %v is not a string", modelVal)
 	}
 
+	metrics.RecordSuccessCounter()
 	return &eppb.ProcessingResponse{
 		Response: &eppb.ProcessingResponse_RequestBody{
 			RequestBody: &eppb.BodyResponse{

Diff for: pkg/body-based-routing/handlers/request_test.go

@@ -18,12 +18,16 @@ package handlers
 
 import (
 	"context"
+	"strings"
 	"testing"
 
 	basepb "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
 	extProcPb "github.com/envoyproxy/go-control-plane/envoy/service/ext_proc/v3"
 	"github.com/google/go-cmp/cmp"
 	"google.golang.org/protobuf/testing/protocmp"
+	"k8s.io/component-base/metrics/legacyregistry"
+	metricsutils "k8s.io/component-base/metrics/testutil"
+	"sigs.k8s.io/gateway-api-inference-extension/pkg/body-based-routing/metrics"
 	logutil "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/util/logging"
 )
 
@@ -48,6 +52,7 @@ const (
 )
 
 func TestHandleRequestBody(t *testing.T) {
+	metrics.Register()
 	ctx := logutil.NewTestLoggerIntoContext(context.Background())
 
 	tests := []struct {
@@ -125,4 +130,20 @@ func TestHandleRequestBody(t *testing.T) {
 			}
 		})
 	}
+
+	wantMetrics := `
+	# HELP bbr_model_not_in_body_total [ALPHA] Count of times the model was not present in the request body.
+	# TYPE bbr_model_not_in_body_total counter
+	bbr_model_not_in_body_total{} 1
+	# HELP bbr_model_not_parsed_total [ALPHA] Count of times the model was in the request body but we could not parse it.
+	# TYPE bbr_model_not_parsed_total counter
+	bbr_model_not_parsed_total{} 1
+	# HELP bbr_success_total [ALPHA] Count of successes pulling model name from body and injecting it in the request headers.
+	# TYPE bbr_success_total counter
+	bbr_success_total{} 1
+	`
+
+	if err := metricsutils.GatherAndCompare(legacyregistry.DefaultGatherer, strings.NewReader(wantMetrics), "inference_model_request_total"); err != nil {
+		t.Error(err)
+	}
 }

Diff for: pkg/body-based-routing/metrics/metrics.go

@@ -0,0 +1,103 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package metrics
+
+import (
+	"sync"
+
+	compbasemetrics "k8s.io/component-base/metrics"
+	"k8s.io/component-base/metrics/legacyregistry"
+)
+
+const component = "bbr"
+
+var (
+	successCounter = compbasemetrics.NewCounterVec(
+		&compbasemetrics.CounterOpts{
+			Subsystem:      component,
+			Name:           "success_total",
+			Help:           "Count of successes pulling model name from body and injecting it in the request headers.",
+			StabilityLevel: compbasemetrics.ALPHA,
+		},
+		[]string{},
+	)
+	modelNotInBodyCounter = compbasemetrics.NewCounterVec(
+		&compbasemetrics.CounterOpts{
+			Subsystem:      component,
+			Name:           "model_not_in_body_total",
+			Help:           "Count of times the model was not present in the request body.",
+			StabilityLevel: compbasemetrics.ALPHA,
+		},
+		[]string{},
+	)
+	modelNotParsedCounter = compbasemetrics.NewCounterVec(
+		&compbasemetrics.CounterOpts{
+			Subsystem:      component,
+			Name:           "model_not_parsed_total",
+			Help:           "Count of times the model was in the request body but we could not parse it.",
+			StabilityLevel: compbasemetrics.ALPHA,
+		},
+		[]string{},
+	)
+
+	// TODO: Uncomment and use this metrics once the core server implementation has handling to skip body parsing if header exists.
+	/*
+		modelAlreadyPresentInHeaderCounter = compbasemetrics.NewCounterVec(
+			&compbasemetrics.CounterOpts{
+				Subsystem:      component,
+				Name:           "model_already_present_in_header_total",
+				Help:           "Count of times the model was already present in request headers.",
+				StabilityLevel: compbasemetrics.ALPHA,
+			},
+			[]string{},
+		)
+	*/
+)
+
+var registerMetrics sync.Once
+
+// Register all metrics.
+func Register() {
+	registerMetrics.Do(func() {
+		legacyregistry.MustRegister(successCounter)
+		legacyregistry.MustRegister(modelNotInBodyCounter)
+		legacyregistry.MustRegister(modelNotParsedCounter)
+		// legacyregistry.MustRegister(modelAlreadyPresentInHeaderCounter)
+	})
+}
+
+// RecordSuccessCounter records the number of successful requests to inject the model name into request headers.
+func RecordSuccessCounter() {
+	successCounter.WithLabelValues().Inc()
+}
+
+// RecordModelNotInBodyCounter records the number of times the model was not found in the request body.
+func RecordModelNotInBodyCounter() {
+	modelNotInBodyCounter.WithLabelValues().Inc()
+}
+
+// RecordModelNotParsedCounter records the number of times the model was found in the body but it could not be parsed.
+func RecordModelNotParsedCounter() {
+	modelNotParsedCounter.WithLabelValues().Inc()
+}
+
+/*
+// RecordModelAlreadyInHeaderCounter records the number of times the model was already found in the request headers.
+func RecordModelAlreadyInHeaderCounter() {
+	modelAlreadyPresentInHeaderCounter.WithLabelValues().Inc()
+}
+*/