Add a no-op GRPC responder service to the podman system service

Add a bare minimum GRPC service to the podman system service socket.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

pkg/api/grpcpb/build.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -e
+cd $(dirname ${BASH_SOURCE[0]})
+TOP=../../..
+PATH=${TOP}/test/tools/build:${PATH}
+set -x
+for proto in *.proto ; do
+	protoc \
+		--go_opt=paths=source_relative --go_out . \
+		--go-grpc_opt=paths=source_relative --go-grpc_out . \
+	${proto}
+done

pkg/api/grpcpb/noop.pb.go

@@ -0,0 +1,174 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.36.10
+// 	protoc        v3.19.6
+// source: noop.proto
+
+package grpcpb
+
+import (
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	reflect "reflect"
+	sync "sync"
+	unsafe "unsafe"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+type NoopRequest struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Ignored       string                 `protobuf:"bytes,1,opt,name=ignored,proto3" json:"ignored,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *NoopRequest) Reset() {
+	*x = NoopRequest{}
+	mi := &file_noop_proto_msgTypes[0]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *NoopRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*NoopRequest) ProtoMessage() {}
+
+func (x *NoopRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_noop_proto_msgTypes[0]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use NoopRequest.ProtoReflect.Descriptor instead.
+func (*NoopRequest) Descriptor() ([]byte, []int) {
+	return file_noop_proto_rawDescGZIP(), []int{0}
+}
+
+func (x *NoopRequest) GetIgnored() string {
+	if x != nil {
+		return x.Ignored
+	}
+	return ""
+}
+
+type NoopResponse struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Ignored       string                 `protobuf:"bytes,1,opt,name=ignored,proto3" json:"ignored,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *NoopResponse) Reset() {
+	*x = NoopResponse{}
+	mi := &file_noop_proto_msgTypes[1]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *NoopResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*NoopResponse) ProtoMessage() {}
+
+func (x *NoopResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_noop_proto_msgTypes[1]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use NoopResponse.ProtoReflect.Descriptor instead.
+func (*NoopResponse) Descriptor() ([]byte, []int) {
+	return file_noop_proto_rawDescGZIP(), []int{1}
+}
+
+func (x *NoopResponse) GetIgnored() string {
+	if x != nil {
+		return x.Ignored
+	}
+	return ""
+}
+
+var File_noop_proto protoreflect.FileDescriptor
+
+const file_noop_proto_rawDesc = "" +
+	"\n" +
+	"\n" +
+	"noop.proto\x12\fio.podman.v1\"'\n" +
+	"\vNoopRequest\x12\x18\n" +
+	"\aignored\x18\x01 \x01(\tR\aignored\"(\n" +
+	"\fNoopResponse\x12\x18\n" +
+	"\aignored\x18\x01 \x01(\tR\aignored2E\n" +
+	"\x04Noop\x12=\n" +
+	"\x04Noop\x12\x19.io.podman.v1.NoopRequest\x1a\x1a.io.podman.v1.NoopResponseB0Z.github.com/containers/podman/v6/pkg/api/grpcpbb\x06proto3"
+
+var (
+	file_noop_proto_rawDescOnce sync.Once
+	file_noop_proto_rawDescData []byte
+)
+
+func file_noop_proto_rawDescGZIP() []byte {
+	file_noop_proto_rawDescOnce.Do(func() {
+		file_noop_proto_rawDescData = protoimpl.X.CompressGZIP(unsafe.Slice(unsafe.StringData(file_noop_proto_rawDesc), len(file_noop_proto_rawDesc)))
+	})
+	return file_noop_proto_rawDescData
+}
+
+var file_noop_proto_msgTypes = make([]protoimpl.MessageInfo, 2)
+var file_noop_proto_goTypes = []any{
+	(*NoopRequest)(nil),  // 0: io.podman.v1.NoopRequest
+	(*NoopResponse)(nil), // 1: io.podman.v1.NoopResponse
+}
+var file_noop_proto_depIdxs = []int32{
+	0, // 0: io.podman.v1.Noop.Noop:input_type -> io.podman.v1.NoopRequest
+	1, // 1: io.podman.v1.Noop.Noop:output_type -> io.podman.v1.NoopResponse
+	1, // [1:2] is the sub-list for method output_type
+	0, // [0:1] is the sub-list for method input_type
+	0, // [0:0] is the sub-list for extension type_name
+	0, // [0:0] is the sub-list for extension extendee
+	0, // [0:0] is the sub-list for field type_name
+}
+
+func init() { file_noop_proto_init() }
+func file_noop_proto_init() {
+	if File_noop_proto != nil {
+		return
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: unsafe.Slice(unsafe.StringData(file_noop_proto_rawDesc), len(file_noop_proto_rawDesc)),
+			NumEnums:      0,
+			NumMessages:   2,
+			NumExtensions: 0,
+			NumServices:   1,
+		},
+		GoTypes:           file_noop_proto_goTypes,
+		DependencyIndexes: file_noop_proto_depIdxs,
+		MessageInfos:      file_noop_proto_msgTypes,
+	}.Build()
+	File_noop_proto = out.File
+	file_noop_proto_goTypes = nil
+	file_noop_proto_depIdxs = nil
+}

pkg/api/grpcpb/noop.proto

@@ -0,0 +1,17 @@
+syntax = "proto3";
+
+package io.podman.v1;
+
+option go_package = "github.com/containers/podman/v6/pkg/api/grpcpb";
+
+service Noop {
+  rpc Noop(NoopRequest) returns (NoopResponse);
+}
+
+message NoopRequest {
+  string ignored = 1;
+}
+
+message NoopResponse {
+  string ignored = 1;
+}

pkg/api/grpcpb/noop_grpc.pb.go

@@ -0,0 +1,121 @@
+// Code generated by protoc-gen-go-grpc. DO NOT EDIT.
+// versions:
+// - protoc-gen-go-grpc v1.5.1
+// - protoc             v3.19.6
+// source: noop.proto
+
+package grpcpb
+
+import (
+	context "context"
+	grpc "google.golang.org/grpc"
+	codes "google.golang.org/grpc/codes"
+	status "google.golang.org/grpc/status"
+)
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the grpc package it is being compiled against.
+// Requires gRPC-Go v1.64.0 or later.
+const _ = grpc.SupportPackageIsVersion9
+
+const (
+	Noop_Noop_FullMethodName = "/io.podman.v1.Noop/Noop"
+)
+
+// NoopClient is the client API for Noop service.
+//
+// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://pkg.go.dev/google.golang.org/grpc/?tab=doc#ClientConn.NewStream.
+type NoopClient interface {
+	Noop(ctx context.Context, in *NoopRequest, opts ...grpc.CallOption) (*NoopResponse, error)
+}
+
+type noopClient struct {
+	cc grpc.ClientConnInterface
+}
+
+func NewNoopClient(cc grpc.ClientConnInterface) NoopClient {
+	return &noopClient{cc}
+}
+
+func (c *noopClient) Noop(ctx context.Context, in *NoopRequest, opts ...grpc.CallOption) (*NoopResponse, error) {
+	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
+	out := new(NoopResponse)
+	err := c.cc.Invoke(ctx, Noop_Noop_FullMethodName, in, out, cOpts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// NoopServer is the server API for Noop service.
+// All implementations must embed UnimplementedNoopServer
+// for forward compatibility.
+type NoopServer interface {
+	Noop(context.Context, *NoopRequest) (*NoopResponse, error)
+	mustEmbedUnimplementedNoopServer()
+}
+
+// UnimplementedNoopServer must be embedded to have
+// forward compatible implementations.
+//
+// NOTE: this should be embedded by value instead of pointer to avoid a nil
+// pointer dereference when methods are called.
+type UnimplementedNoopServer struct{}
+
+func (UnimplementedNoopServer) Noop(context.Context, *NoopRequest) (*NoopResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Noop not implemented")
+}
+func (UnimplementedNoopServer) mustEmbedUnimplementedNoopServer() {}
+func (UnimplementedNoopServer) testEmbeddedByValue()              {}
+
+// UnsafeNoopServer may be embedded to opt out of forward compatibility for this service.
+// Use of this interface is not recommended, as added methods to NoopServer will
+// result in compilation errors.
+type UnsafeNoopServer interface {
+	mustEmbedUnimplementedNoopServer()
+}
+
+func RegisterNoopServer(s grpc.ServiceRegistrar, srv NoopServer) {
+	// If the following call pancis, it indicates UnimplementedNoopServer was
+	// embedded by pointer and is nil.  This will cause panics if an
+	// unimplemented method is ever invoked, so we test this at initialization
+	// time to prevent it from happening at runtime later due to I/O.
+	if t, ok := srv.(interface{ testEmbeddedByValue() }); ok {
+		t.testEmbeddedByValue()
+	}
+	s.RegisterService(&Noop_ServiceDesc, srv)
+}
+
+func _Noop_Noop_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(NoopRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(NoopServer).Noop(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: Noop_Noop_FullMethodName,
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(NoopServer).Noop(ctx, req.(*NoopRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+// Noop_ServiceDesc is the grpc.ServiceDesc for Noop service.
+// It's only intended for direct use with grpc.RegisterService,
+// and not to be introspected or modified (even as a copy)
+var Noop_ServiceDesc = grpc.ServiceDesc{
+	ServiceName: "io.podman.v1.Noop",
+	HandlerType: (*NoopServer)(nil),
+	Methods: []grpc.MethodDesc{
+		{
+			MethodName: "Noop",
+			Handler:    _Noop_Noop_Handler,
+		},
+	},
+	Streams:  []grpc.StreamDesc{},
+	Metadata: "noop.proto",
+}

pkg/api/handlers/grpc/noop.go

@@ -0,0 +1,26 @@
+//go:build !remote
+
+package grpc
+
+import (
+	"context"
+
+	"github.com/containers/podman/v6/libpod"
+	"github.com/containers/podman/v6/pkg/api/grpcpb"
+)
+
+type noopServer struct {
+	grpcpb.UnimplementedNoopServer
+	runtime *libpod.Runtime
+}
+
+func (noopServer) Noop(_ context.Context, req *grpcpb.NoopRequest) (*grpcpb.NoopResponse, error) {
+	resp := &grpcpb.NoopResponse{
+		Ignored: req.GetIgnored(),
+	}
+	return resp, nil
+}
+
+func NewNoopServer(runtime *libpod.Runtime) grpcpb.NoopServer {
+	return &noopServer{runtime: runtime}
+}

pkg/api/server/server.go

@@ -19,7 +19,9 @@ import (
 
 	"github.com/containers/podman/v6/libpod"
 	"github.com/containers/podman/v6/libpod/shutdown"
+	"github.com/containers/podman/v6/pkg/api/grpcpb"
 	"github.com/containers/podman/v6/pkg/api/handlers"
+	grpchandlers "github.com/containers/podman/v6/pkg/api/handlers/grpc"
 	"github.com/containers/podman/v6/pkg/api/server/idle"
 	"github.com/containers/podman/v6/pkg/api/types"
 	"github.com/containers/podman/v6/pkg/domain/entities"
@@ -28,12 +30,13 @@ import (
 	"github.com/gorilla/mux"
 	"github.com/gorilla/schema"
 	"github.com/sirupsen/logrus"
-	_ "google.golang.org/grpc"
-	_ "google.golang.org/grpc/reflection"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/reflection"
 )
 
 type APIServer struct {
-	http.Server                      // The  HTTP work happens here
+	http.Server                      // The HTTP work happens here
+	grpc               *grpc.Server  // GRPC stuff happens here
 	net.Listener                     // mux for routing HTTP API calls to libpod routines
 	*libpod.Runtime                  // Where the real work happens
 	*schema.Decoder                  // Decoder for Query parameters to structs
@@ -73,6 +76,10 @@ func newServer(runtime *libpod.Runtime, listener net.Listener, opts entities.Ser
 	router := mux.NewRouter().UseEncodedPath()
 	tracker := idle.NewTracker(opts.Timeout)
 
+	serverProtocols := &http.Protocols{}
+	serverProtocols.SetHTTP1(true)
+	serverProtocols.SetHTTP2(true)
+
 	server := APIServer{
 		Server: http.Server{
 			ConnContext: func(ctx context.Context, c net.Conn) context.Context {
@@ -82,7 +89,9 @@ func newServer(runtime *libpod.Runtime, listener net.Listener, opts entities.Ser
 			ErrorLog:    log.New(logrus.StandardLogger().Out, "", 0),
 			Handler:     router,
 			IdleTimeout: opts.Timeout * 2,
+			Protocols:   serverProtocols,
 		},
+		grpc:            grpc.NewServer(),
 		CorsHeaders:     opts.CorsHeaders,
 		Listener:        listener,
 		PProfAddr:       opts.PProfAddr,
@@ -92,6 +101,9 @@ func newServer(runtime *libpod.Runtime, listener net.Listener, opts entities.Ser
 		tlsClientCAFile: opts.TLSClientCAFile,
 	}
 
+	router.NewRoute().HeadersRegexp("Content-Type", "application/grpc(\\+.*)?").Handler(server.grpc)
+	reflection.Register(server.grpc)
+
 	server.BaseContext = func(_ net.Listener) context.Context {
 		ctx := context.WithValue(context.Background(), types.DecoderKey, handlers.NewAPIDecoder())
 		ctx = context.WithValue(ctx, types.CompatDecoderKey, handlers.NewCompatAPIDecoder())
@@ -163,6 +175,8 @@ func newServer(runtime *libpod.Runtime, listener net.Listener, opts entities.Ser
 		}
 	}
 
+	grpcpb.RegisterNoopServer(server.grpc, grpchandlers.NewNoopServer(runtime)) // TODO: make this table-driven instead of a one-off?
+
 	if logrus.IsLevelEnabled(logrus.TraceLevel) {
 		// If in trace mode log request and response bodies
 		router.Use(loggingHandler())
@@ -213,6 +227,7 @@ func (s *APIServer) Serve() error {
 	s.setupPprof()
 
 	if err := shutdown.Register("service", func(_ os.Signal) error {
+		s.grpc.GracefulStop()
 		err := s.Shutdown(true)
 		if err == nil {
 			// For `systemctl stop podman.service` support, exit code should be 0
@@ -247,6 +262,7 @@ func (s *APIServer) Serve() error {
 			}
 			err = s.Server.ServeTLS(s.Listener, s.tlsCertFile, s.tlsKeyFile)
 		} else {
+			s.Server.Protocols.SetUnencryptedHTTP2(true)
 			err = s.Server.Serve(s.Listener)
 		}
 		if err != nil && err != http.ErrServerClosed {