Support gRPC probe

config/core/300-resources/configuration.yaml

@@ -247,6 +247,19 @@ spec:
                                     description: Minimum consecutive failures for the probe to be considered failed after having succeeded. Defaults to 3. Minimum value is 1.
                                     type: integer
                                     format: int32
+                                  grpc:
+                                    description: GRPC specifies an action involving a GRPC port. This is a beta field and requires enabling GRPCContainerProbe feature gate.
+                                    type: object
+                                    required:
+                                      - port
+                                    properties:
+                                      port:
+                                        description: Port number of the gRPC service. Number must be in the range 1 to 65535.
+                                        type: integer
+                                        format: int32
+                                      service:
+                                        description: "Service is the name of the service to place in the gRPC HealthCheckRequest (see https://github.com/grpc/grpc/blob/master/doc/health-checking.md). \n If this is not specified, the default behavior is defined by gRPC."
+                                        type: string
                                   httpGet:
                                     description: HTTPGet specifies the http request to perform.
                                     type: object
@@ -355,6 +368,19 @@ spec:
                                     description: Minimum consecutive failures for the probe to be considered failed after having succeeded. Defaults to 3. Minimum value is 1.
                                     type: integer
                                     format: int32
+                                  grpc:
+                                    description: GRPC specifies an action involving a GRPC port. This is a beta field and requires enabling GRPCContainerProbe feature gate.
+                                    type: object
+                                    required:
+                                      - port
+                                    properties:
+                                      port:
+                                        description: Port number of the gRPC service. Number must be in the range 1 to 65535.
+                                        type: integer
+                                        format: int32
+                                      service:
+                                        description: "Service is the name of the service to place in the gRPC HealthCheckRequest (see https://github.com/grpc/grpc/blob/master/doc/health-checking.md). \n If this is not specified, the default behavior is defined by gRPC."
+                                        type: string
                                   httpGet:
                                     description: HTTPGet specifies the http request to perform.
                                     type: object

config/core/300-resources/revision.yaml

@@ -226,6 +226,19 @@ spec:
                             description: Minimum consecutive failures for the probe to be considered failed after having succeeded. Defaults to 3. Minimum value is 1.
                             type: integer
                             format: int32
+                          grpc:
+                            description: GRPC specifies an action involving a GRPC port. This is a beta field and requires enabling GRPCContainerProbe feature gate.
+                            type: object
+                            required:
+                              - port
+                            properties:
+                              port:
+                                description: Port number of the gRPC service. Number must be in the range 1 to 65535.
+                                type: integer
+                                format: int32
+                              service:
+                                description: "Service is the name of the service to place in the gRPC HealthCheckRequest (see https://github.com/grpc/grpc/blob/master/doc/health-checking.md). \n If this is not specified, the default behavior is defined by gRPC."
+                                type: string
                           httpGet:
                             description: HTTPGet specifies the http request to perform.
                             type: object
@@ -334,6 +347,19 @@ spec:
                             description: Minimum consecutive failures for the probe to be considered failed after having succeeded. Defaults to 3. Minimum value is 1.
                             type: integer
                             format: int32
+                          grpc:
+                            description: GRPC specifies an action involving a GRPC port. This is a beta field and requires enabling GRPCContainerProbe feature gate.
+                            type: object
+                            required:
+                              - port
+                            properties:
+                              port:
+                                description: Port number of the gRPC service. Number must be in the range 1 to 65535.
+                                type: integer
+                                format: int32
+                              service:
+                                description: "Service is the name of the service to place in the gRPC HealthCheckRequest (see https://github.com/grpc/grpc/blob/master/doc/health-checking.md). \n If this is not specified, the default behavior is defined by gRPC."
+                                type: string
                           httpGet:
                             description: HTTPGet specifies the http request to perform.
                             type: object

config/core/300-resources/service.yaml

@@ -251,6 +251,19 @@ spec:
                                     description: Minimum consecutive failures for the probe to be considered failed after having succeeded. Defaults to 3. Minimum value is 1.
                                     type: integer
                                     format: int32
+                                  grpc:
+                                    description: GRPC specifies an action involving a GRPC port. This is a beta field and requires enabling GRPCContainerProbe feature gate.
+                                    type: object
+                                    required:
+                                      - port
+                                    properties:
+                                      port:
+                                        description: Port number of the gRPC service. Number must be in the range 1 to 65535.
+                                        type: integer
+                                        format: int32
+                                      service:
+                                        description: "Service is the name of the service to place in the gRPC HealthCheckRequest (see https://github.com/grpc/grpc/blob/master/doc/health-checking.md). \n If this is not specified, the default behavior is defined by gRPC."
+                                        type: string
                                   httpGet:
                                     description: HTTPGet specifies the http request to perform.
                                     type: object
@@ -359,6 +372,19 @@ spec:
                                     description: Minimum consecutive failures for the probe to be considered failed after having succeeded. Defaults to 3. Minimum value is 1.
                                     type: integer
                                     format: int32
+                                  grpc:
+                                    description: GRPC specifies an action involving a GRPC port. This is a beta field and requires enabling GRPCContainerProbe feature gate.
+                                    type: object
+                                    required:
+                                      - port
+                                    properties:
+                                      port:
+                                        description: Port number of the gRPC service. Number must be in the range 1 to 65535.
+                                        type: integer
+                                        format: int32
+                                      service:
+                                        description: "Service is the name of the service to place in the gRPC HealthCheckRequest (see https://github.com/grpc/grpc/blob/master/doc/health-checking.md). \n If this is not specified, the default behavior is defined by gRPC."
+                                        type: string
                                   httpGet:
                                     description: HTTPGet specifies the http request to perform.
                                     type: object

go.mod

@@ -22,6 +22,7 @@ require (
 	go.uber.org/zap v1.25.0
 	golang.org/x/net v0.15.0
 	golang.org/x/sync v0.3.0
+	golang.org/x/sys v0.12.0
 	golang.org/x/time v0.3.0
 	google.golang.org/api v0.140.0
 	google.golang.org/grpc v1.58.0
@@ -139,7 +140,6 @@ require (
 	golang.org/x/crypto v0.13.0 // indirect
 	golang.org/x/mod v0.12.0 // indirect
 	golang.org/x/oauth2 v0.12.0 // indirect
-	golang.org/x/sys v0.12.0 // indirect
 	golang.org/x/term v0.12.0 // indirect
 	golang.org/x/text v0.13.0 // indirect
 	golang.org/x/tools v0.13.0 // indirect

hack/schemapatch-config.yaml

@@ -198,6 +198,11 @@ k8s.io/api/core/v1.ProbeHandler:
     - Exec
     - HTTPGet
     - TCPSocket
+    - GRPC
+k8s.io/api/core/v1.GRPCAction:
+  fieldMask:
+    - Port
+    - Service
 k8s.io/api/core/v1.ExecAction:
   fieldMask:
     - Command

pkg/apis/serving/fieldmask.go

@@ -374,6 +374,7 @@ func HandlerMask(in *corev1.ProbeHandler) *corev1.ProbeHandler {
 	out.Exec = in.Exec
 	out.HTTPGet = in.HTTPGet
 	out.TCPSocket = in.TCPSocket
+	out.GRPC = in.GRPC
 
 	return out
 
@@ -429,6 +430,22 @@ func TCPSocketActionMask(in *corev1.TCPSocketAction) *corev1.TCPSocketAction {
 	return out
 }
 
+// GRPCActionMask performs a _shallow_ copy of the Kubernetes GRPCAction object to a new
+// Kubernetes GRPCAction object bringing over only the fields allowed in the Knative API. This
+// does not validate the contents or the bounds of the provided fields.
+func GRPCActionMask(in *corev1.GRPCAction) *corev1.GRPCAction {
+	if in == nil {
+		return nil
+	}
+	out := new(corev1.GRPCAction)
+
+	// Allowed fields
+	out.Port = in.Port
+	out.Service = in.Service
+
+	return out
+}
+
 // ContainerPortMask performs a _shallow_ copy of the Kubernetes ContainerPort object to a new
 // Kubernetes ContainerPort object bringing over only the fields allowed in the Knative API. This
 // does not validate the contents or the bounds of the provided fields.

pkg/apis/serving/fieldmask_test.go

@@ -318,6 +318,7 @@ func TestHandlerMask(t *testing.T) {
 		Exec:      &corev1.ExecAction{},
 		HTTPGet:   &corev1.HTTPGetAction{},
 		TCPSocket: &corev1.TCPSocketAction{},
+		GRPC:      &corev1.GRPCAction{},
 	}
 	in := want
 
@@ -421,6 +422,33 @@ func TestTCPSocketActionMask(t *testing.T) {
 	}
 }
 
+func TestGRPCActionMask(t *testing.T) {
+	want := &corev1.GRPCAction{
+		Port:    42,
+		Service: ptr.String("foo"),
+	}
+	in := &corev1.GRPCAction{
+		Port:    42,
+		Service: ptr.String("foo"),
+	}
+
+	got := GRPCActionMask(in)
+
+	if &want == &got {
+		t.Error("Input and output share addresses. Want different addresses")
+	}
+
+	if diff, err := kmp.SafeDiff(want, got); err != nil {
+		t.Error("Got error comparing output, err =", err)
+	} else if diff != "" {
+		t.Error("GRPCActionMask (-want, +got):", diff)
+	}
+
+	if got = GRPCActionMask(nil); got != nil {
+		t.Errorf("GRPCActionMask(nil) = %v, want: nil", got)
+	}
+}
+
 func TestContainerPortMask(t *testing.T) {
 	want := &corev1.ContainerPort{
 		ContainerPort: 42,

pkg/apis/serving/k8s_validation.go

@@ -832,9 +832,13 @@ func validateProbe(p *corev1.Probe, port corev1.ContainerPort) *apis.FieldError
 		handlers = append(handlers, "exec")
 		errs = errs.Also(apis.CheckDisallowedFields(*h.Exec, *ExecActionMask(h.Exec))).ViaField("exec")
 	}
+	if h.GRPC != nil {
+		handlers = append(handlers, "gRPC")
+		errs = errs.Also(apis.CheckDisallowedFields(*h.GRPC, *GRPCActionMask(h.GRPC))).ViaField("grpc")
+	}
 
 	if len(handlers) == 0 {
-		errs = errs.Also(apis.ErrMissingOneOf("httpGet", "tcpSocket", "exec"))
+		errs = errs.Also(apis.ErrMissingOneOf("httpGet", "tcpSocket", "exec", "grpc"))
 	} else if len(handlers) > 1 {
 		errs = errs.Also(apis.ErrMultipleOneOf(handlers...))
 	}

pkg/apis/serving/k8s_validation_test.go

@@ -1654,7 +1654,7 @@ func TestContainerValidation(t *testing.T) {
 					ProbeHandler: corev1.ProbeHandler{},
 				},
 			},
-			want: apis.ErrMissingOneOf("livenessProbe.httpGet", "livenessProbe.tcpSocket", "livenessProbe.exec"),
+			want: apis.ErrMissingOneOf("livenessProbe.httpGet", "livenessProbe.tcpSocket", "livenessProbe.exec", "livenessProbe.grpc"),
 		}, {
 			name: "invalid with multiple handlers",
 			c: corev1.Container{
@@ -1888,6 +1888,39 @@ func TestContainerValidation(t *testing.T) {
 			},
 			want: apis.ErrDisallowedFields("lifecycle").Also(
 				apis.ErrMissingField("image")),
+		}, {
+			name: "valid grpc probe",
+			c: corev1.Container{
+				Image: "foo",
+				ReadinessProbe: &corev1.Probe{
+					PeriodSeconds:    1,
+					TimeoutSeconds:   1,
+					SuccessThreshold: 1,
+					FailureThreshold: 3,
+					ProbeHandler: corev1.ProbeHandler{
+						GRPC: &corev1.GRPCAction{
+							Port: 46,
+						},
+					},
+				},
+			},
+		}, {
+			name: "valid grpc probe with service",
+			c: corev1.Container{
+				Image: "foo",
+				ReadinessProbe: &corev1.Probe{
+					PeriodSeconds:    1,
+					TimeoutSeconds:   1,
+					SuccessThreshold: 1,
+					FailureThreshold: 3,
+					ProbeHandler: corev1.ProbeHandler{
+						GRPC: &corev1.GRPCAction{
+							Port:    46,
+							Service: ptr.String("foo"),
+						},
+					},
+				},
+			},
 		},
 	}
 	tests = append(tests, getCommonContainerValidationTestCases()...)

pkg/apis/serving/v1/revision_defaults.go

@@ -143,10 +143,15 @@ func (*RevisionSpec) applyProbes(container *corev1.Container) {
 	}
 	if container.ReadinessProbe.TCPSocket == nil &&
 		container.ReadinessProbe.HTTPGet == nil &&
-		container.ReadinessProbe.Exec == nil {
+		container.ReadinessProbe.Exec == nil &&
+		container.ReadinessProbe.GRPC == nil {
 		container.ReadinessProbe.TCPSocket = &corev1.TCPSocketAction{}
 	}
 
+	if container.ReadinessProbe.GRPC != nil && container.ReadinessProbe.GRPC.Service == nil {
+		container.ReadinessProbe.GRPC.Service = ptr.String("")
+	}
+
 	if container.ReadinessProbe.SuccessThreshold == 0 {
 		container.ReadinessProbe.SuccessThreshold = 1
 	}