Adds Health gRPC Server and Refactors Main() (kubernetes-sigs#148)

* Add health gRPC server and refactors main()

- Introduced a health gRPC server to handle liveness and readiness probes.
- Refactored main() to manage server goroutines.
- Added graceful shutdown for servers and controller manager.
- Improved logging consistency and ensured.
- Validates CLI flags.

Signed-off-by: Daneyon Hansen <[email protected]>

* Refactors health server to use data store

Signed-off-by: Daneyon Hansen <[email protected]>

---------

Signed-off-by: Daneyon Hansen <[email protected]>

Author: danehans

pkg/ext-proc/backend/datastore.go

@@ -52,8 +52,8 @@ func (ds *K8sDatastore) setInferencePool(pool *v1alpha1.InferencePool) {
 func (ds *K8sDatastore) getInferencePool() (*v1alpha1.InferencePool, error) {
 	ds.poolMu.RLock()
 	defer ds.poolMu.RUnlock()
-	if ds.inferencePool == nil {
-		return nil, errors.New("InferencePool hasn't been initialized yet")
+	if !ds.HasSynced() {
+		return nil, errors.New("InferencePool is not initialized in data store")
 	}
 	return ds.inferencePool, nil
 }
@@ -75,6 +75,13 @@ func (s *K8sDatastore) FetchModelData(modelName string) (returnModel *v1alpha1.I
 	return
 }
 
+// HasSynced returns true if InferencePool is set in the data store.
+func (ds *K8sDatastore) HasSynced() bool {
+	ds.poolMu.RLock()
+	defer ds.poolMu.RUnlock()
+	return ds.inferencePool != nil
+}
+
 func RandomWeightedDraw(model *v1alpha1.InferenceModel, seed int64) string {
 	var weights int32
 

pkg/ext-proc/backend/datastore_test.go

@@ -4,8 +4,47 @@ import (
 	"testing"
 
 	"inference.networking.x-k8s.io/gateway-api-inference-extension/api/v1alpha1"
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
+func TestHasSynced(t *testing.T) {
+	tests := []struct {
+		name          string
+		inferencePool *v1alpha1.InferencePool
+		hasSynced     bool
+	}{
+		{
+			name: "Ready when InferencePool exists in data store",
+			inferencePool: &v1alpha1.InferencePool{
+				ObjectMeta: v1.ObjectMeta{
+					Name:      "test-pool",
+					Namespace: "default",
+				},
+			},
+			hasSynced: true,
+		},
+		{
+			name:          "Not ready when InferencePool is nil in data store",
+			inferencePool: nil,
+			hasSynced:     false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			datastore := NewK8sDataStore()
+			// Set the inference pool
+			if tt.inferencePool != nil {
+				datastore.setInferencePool(tt.inferencePool)
+			}
+			// Check if the data store has been initialized
+			hasSynced := datastore.HasSynced()
+			if hasSynced != tt.hasSynced {
+				t.Errorf("IsInitialized() = %v, want %v", hasSynced, tt.hasSynced)
+			}
+		})
+	}
+}
+
 func TestRandomWeightedDraw(t *testing.T) {
 	tests := []struct {
 		name  string

pkg/ext-proc/health.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"context"
+
+	"google.golang.org/grpc/codes"
+	healthPb "google.golang.org/grpc/health/grpc_health_v1"
+	"google.golang.org/grpc/status"
+	"inference.networking.x-k8s.io/gateway-api-inference-extension/pkg/ext-proc/backend"
+	klog "k8s.io/klog/v2"
+)
+
+type healthServer struct {
+	datastore *backend.K8sDatastore
+}
+
+func (s *healthServer) Check(ctx context.Context, in *healthPb.HealthCheckRequest) (*healthPb.HealthCheckResponse, error) {
+	if !s.datastore.HasSynced() {
+		klog.Infof("gRPC health check not serving: %s", in.String())
+		return &healthPb.HealthCheckResponse{Status: healthPb.HealthCheckResponse_NOT_SERVING}, nil
+	}
+	klog.Infof("gRPC health check serving: %s", in.String())
+	return &healthPb.HealthCheckResponse{Status: healthPb.HealthCheckResponse_SERVING}, nil
+}
+
+func (s *healthServer) Watch(in *healthPb.HealthCheckRequest, srv healthPb.Health_WatchServer) error {
+	return status.Error(codes.Unimplemented, "Watch is not implemented")
+}

pkg/ext-proc/main.go

@@ -1,20 +1,14 @@
 package main
 
 import (
-	"context"
 	"flag"
 	"fmt"
 	"net"
-	"os"
-	"os/signal"
-	"syscall"
 	"time"
 
 	extProcPb "github.com/envoyproxy/go-control-plane/envoy/service/ext_proc/v3"
 	"google.golang.org/grpc"
-	"google.golang.org/grpc/codes"
 	healthPb "google.golang.org/grpc/health/grpc_health_v1"
-	"google.golang.org/grpc/status"
 	"inference.networking.x-k8s.io/gateway-api-inference-extension/api/v1alpha1"
 	"inference.networking.x-k8s.io/gateway-api-inference-extension/pkg/ext-proc/backend"
 	"inference.networking.x-k8s.io/gateway-api-inference-extension/pkg/ext-proc/backend/vllm"
@@ -29,10 +23,14 @@ import (
 )
 
 var (
-	port = flag.Int(
-		"port",
+	grpcPort = flag.Int(
+		"grpcPort",
 		9002,
-		"gRPC port")
+		"The gRPC port used for communicating with Envoy proxy")
+	grpcHealthPort = flag.Int(
+		"grpcHealthPort",
+		9003,
+		"The port used for gRPC liveness and readiness probes")
 	targetPodHeader = flag.String(
 		"targetPodHeader",
 		"target-pod",
@@ -65,55 +63,39 @@ var (
 	scheme = runtime.NewScheme()
 )
 
-type healthServer struct{}
-
-func (s *healthServer) Check(
-	ctx context.Context,
-	in *healthPb.HealthCheckRequest,
-) (*healthPb.HealthCheckResponse, error) {
-	klog.Infof("Handling grpc Check request + %s", in.String())
-	return &healthPb.HealthCheckResponse{Status: healthPb.HealthCheckResponse_SERVING}, nil
-}
-
-func (s *healthServer) Watch(in *healthPb.HealthCheckRequest, srv healthPb.Health_WatchServer) error {
-	return status.Error(codes.Unimplemented, "Watch is not implemented")
-}
-
 func init() {
 	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
 	utilruntime.Must(v1alpha1.AddToScheme(scheme))
 }
 
 func main() {
-
 	klog.InitFlags(nil)
 	flag.Parse()
 
 	ctrl.SetLogger(klog.TODO())
 
+	// Validate flags
+	if err := validateFlags(); err != nil {
+		klog.Fatalf("Failed to validate flags: %v", err)
+	}
+
 	// Print all flag values
 	flags := "Flags: "
 	flag.VisitAll(func(f *flag.Flag) {
 		flags += fmt.Sprintf("%s=%v; ", f.Name, f.Value)
 	})
 	klog.Info(flags)
 
-	klog.Infof("Listening on %q", fmt.Sprintf(":%d", *port))
-	lis, err := net.Listen("tcp", fmt.Sprintf(":%d", *port))
+	// Create a new manager to manage controllers
+	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{Scheme: scheme})
 	if err != nil {
-		klog.Fatalf("failed to listen: %v", err)
+		klog.Fatalf("Failed to create controller manager: %v", err)
 	}
 
+	// Create the data store used to cache watched resources
 	datastore := backend.NewK8sDataStore()
 
-	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
-		Scheme: scheme,
-	})
-	if err != nil {
-		klog.Error(err, "unable to start manager")
-		os.Exit(1)
-	}
-
+	// Create the controllers and register them with the manager
 	if err := (&backend.InferencePoolReconciler{
 		Datastore: datastore,
 		Scheme:    mgr.GetScheme(),
@@ -124,7 +106,7 @@ func main() {
 		},
 		Record: mgr.GetEventRecorderFor("InferencePool"),
 	}).SetupWithManager(mgr); err != nil {
-		klog.Error(err, "Error setting up InferencePoolReconciler")
+		klog.Fatalf("Failed setting up InferencePoolReconciler: %v", err)
 	}
 
 	if err := (&backend.InferenceModelReconciler{
@@ -137,7 +119,7 @@ func main() {
 		},
 		Record: mgr.GetEventRecorderFor("InferenceModel"),
 	}).SetupWithManager(mgr); err != nil {
-		klog.Error(err, "Error setting up InferenceModelReconciler")
+		klog.Fatalf("Failed setting up InferenceModelReconciler: %v", err)
 	}
 
 	if err := (&backend.EndpointSliceReconciler{
@@ -148,53 +130,105 @@ func main() {
 		ServiceName: *serviceName,
 		Zone:        *zone,
 	}).SetupWithManager(mgr); err != nil {
-		klog.Error(err, "Error setting up EndpointSliceReconciler")
+		klog.Fatalf("Failed setting up EndpointSliceReconciler: %v", err)
+	}
+
+	// Start health and ext-proc servers in goroutines
+	healthSvr := startHealthServer(datastore, *grpcHealthPort)
+	extProcSvr := startExternalProcessorServer(
+		datastore,
+		*grpcPort,
+		*refreshPodsInterval,
+		*refreshMetricsInterval,
+		*targetPodHeader,
+	)
+
+	// Start the controller manager. Blocking and will return when shutdown is complete.
+	klog.Infof("Starting controller manager")
+	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
+		klog.Fatalf("Error starting controller manager: %v", err)
+	}
+	klog.Info("Controller manager shutting down")
+
+	// Gracefully shutdown servers
+	if healthSvr != nil {
+		klog.Info("Health server shutting down")
+		healthSvr.GracefulStop()
 	}
+	if extProcSvr != nil {
+		klog.Info("Ext-proc server shutting down")
+		extProcSvr.GracefulStop()
+	}
+
+	klog.Info("All components shutdown")
+}
+
+// startHealthServer starts the gRPC health probe server in a goroutine.
+func startHealthServer(ds *backend.K8sDatastore, port int) *grpc.Server {
+	svr := grpc.NewServer()
+	healthPb.RegisterHealthServer(svr, &healthServer{datastore: ds})
 
-	errChan := make(chan error)
 	go func() {
-		if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
-			klog.Error(err, "Error running manager")
-			errChan <- err
+		lis, err := net.Listen("tcp", fmt.Sprintf(":%d", port))
+		if err != nil {
+			klog.Fatalf("Health server failed to listen: %v", err)
 		}
+		klog.Infof("Health server listening on port: %d", port)
+
+		// Blocking and will return when shutdown is complete.
+		if err := svr.Serve(lis); err != nil && err != grpc.ErrServerStopped {
+			klog.Fatalf("Health server failed: %v", err)
+		}
+		klog.Info("Health server shutting down")
 	}()
+	return svr
+}
 
-	s := grpc.NewServer()
+// startExternalProcessorServer starts the Envoy external processor server in a goroutine.
+func startExternalProcessorServer(
+	datastore *backend.K8sDatastore,
+	port int,
+	refreshPodsInterval, refreshMetricsInterval time.Duration,
+	targetPodHeader string,
+) *grpc.Server {
+	svr := grpc.NewServer()
 
-	pp := backend.NewProvider(&vllm.PodMetricsClientImpl{}, datastore)
-	if err := pp.Init(*refreshPodsInterval, *refreshMetricsInterval); err != nil {
-		klog.Fatalf("failed to initialize: %v", err)
-	}
-	extProcPb.RegisterExternalProcessorServer(
-		s,
-		handlers.NewServer(
-			pp,
-			scheduling.NewScheduler(pp),
-			*targetPodHeader,
-			datastore))
-	healthPb.RegisterHealthServer(s, &healthServer{})
-
-	klog.Infof("Starting gRPC server on port :%v", *port)
-
-	// shutdown
-	var gracefulStop = make(chan os.Signal, 1)
-	signal.Notify(gracefulStop, syscall.SIGTERM)
-	signal.Notify(gracefulStop, syscall.SIGINT)
 	go func() {
-		select {
-		case sig := <-gracefulStop:
-			klog.Infof("caught sig: %+v", sig)
-			os.Exit(0)
-		case err := <-errChan:
-			klog.Infof("caught error in controller: %+v", err)
-			os.Exit(0)
+		lis, err := net.Listen("tcp", fmt.Sprintf(":%d", port))
+		if err != nil {
+			klog.Fatalf("Ext-proc server failed to listen: %v", err)
 		}
+		klog.Infof("Ext-proc server listening on port: %d", port)
 
+		// Initialize backend provider
+		pp := backend.NewProvider(&vllm.PodMetricsClientImpl{}, datastore)
+		if err := pp.Init(refreshPodsInterval, refreshMetricsInterval); err != nil {
+			klog.Fatalf("Failed to initialize backend provider: %v", err)
+		}
+
+		// Register ext_proc handlers
+		extProcPb.RegisterExternalProcessorServer(
+			svr,
+			handlers.NewServer(pp, scheduling.NewScheduler(pp), targetPodHeader, datastore),
+		)
+
+		// Blocking and will return when shutdown is complete.
+		if err := svr.Serve(lis); err != nil && err != grpc.ErrServerStopped {
+			klog.Fatalf("Ext-proc server failed: %v", err)
+		}
+		klog.Info("Ext-proc server shutting down")
 	}()
+	return svr
+}
 
-	err = s.Serve(lis)
-	if err != nil {
-		klog.Fatalf("Ext-proc failed with the err: %v", err)
+func validateFlags() error {
+	if *poolName == "" {
+		return fmt.Errorf("required %q flag not set", "poolName")
+	}
+
+	if *serviceName == "" {
+		return fmt.Errorf("required %q flag not set", "serviceName")
 	}
 
+	return nil
 }

pkg/manifests/ext_proc.yaml

@@ -28,7 +28,6 @@ roleRef:
   kind: ClusterRole
   name: pod-read
 ---
-
 apiVersion: apps/v1
 kind: Deployment
 metadata:
@@ -57,8 +56,25 @@ spec:
         - "3"
         - -serviceName
         - "vllm-llama2-7b-pool"
+        - -grpcPort
+        - "9002"
+        - -grpcHealthPort
+        - "9003"
         ports:
         - containerPort: 9002
+        - containerPort: 9003
+        livenessProbe:
+          grpc:
+            port: 9003
+            service: inference-extension
+          initialDelaySeconds: 5
+          periodSeconds: 10
+        readinessProbe:
+          grpc:
+            port: 9003
+            service: inference-extension
+          initialDelaySeconds: 5
+          periodSeconds: 10
 ---
 apiVersion: v1
 kind: Service