daemon/extensions: Expose bootstrap configuration to extensions

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

daemon/daemon.go

@@ -956,7 +956,7 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S
 
 	// Build the host after installing the cleanup defer: this starts extension
 	// processes and must be covered if initialization fails.
-	d.extensionHost, err = newExtensionHost(ctx, config)
+	d.extensionHost, err = d.newExtensionHost(ctx)
 	if err != nil {
 		return nil, err
 	}

daemon/extensions.go

@@ -10,7 +10,6 @@ import (
 	"github.com/moby/extensions"
 	"github.com/moby/extensions/grpcproxy"
 	"github.com/moby/extensions/host"
-	"github.com/moby/extensions/serverpoint"
 	"github.com/moby/moby/v2/daemon/config"
 	"github.com/moby/moby/v2/daemon/internal/rootless"
 	servicegrpcv0 "github.com/moby/moby/v2/extpoints/servicegrpc/v0"
@@ -19,7 +18,8 @@ import (
 )
 
 // newExtensionHost builds the daemon's extension host.
-func newExtensionHost(ctx context.Context, cfg *config.Config) (*host.Host, error) {
+func (daemon *Daemon) newExtensionHost(ctx context.Context) (*host.Host, error) {
+	cfg := daemon.Config()
 	runtimeDir := filepath.Join(cfg.ExecRoot, "extensions")
 	if err := os.MkdirAll(runtimeDir, 0o700); err != nil {
 		return nil, fmt.Errorf("create extension runtime directory: %w", err)
@@ -29,22 +29,18 @@ func newExtensionHost(ctx context.Context, cfg *config.Config) (*host.Host, erro
 	}
 	return host.New(ctx,
 		host.WithRuntimeDir(runtimeDir),
-		host.WithExtensions(builtinExtensions(cfg)...),
-		host.WithDirs(extensionDirs(cfg)...),
+		host.WithExtensions(builtinExtensions...),
+		host.WithExtensions(daemon.daemonExtensions()...),
+		host.WithDirs(extensionDirs(&cfg)...),
 		host.WithClientProviders(clientProviders()...),
 		host.WithProviderPolicy(host.PointPolicyFunc(func(extensions.ExtensionIdentity, extensions.PointID) host.PointPolicyResult {
 			return host.Allow()
 		})),
 		host.WithDependencyProviders(dependencyProviders()...),
-		host.WithExtensionConfig(extensionConfig(cfg)),
+		host.WithExtensionConfig(extensionConfig(&cfg)),
 	)
 }
 
-// dependencyProviders lists points that launched extensions may call back into.
-func dependencyProviders() []serverpoint.Registration {
-	return nil
-}
-
 // extensionConfig converts daemon.json's extension-config entries to host form.
 func extensionConfig(cfg *config.Config) map[extensions.ExtensionID]extensions.Config {
 	if len(cfg.ExtensionConfig) == 0 {

daemon/extensions_default.go

@@ -3,14 +3,36 @@ package daemon
 import (
 	"github.com/moby/extensions"
 	"github.com/moby/extensions/clientpoint"
-	"github.com/moby/moby/v2/daemon/config"
+	"github.com/moby/extensions/serverpoint"
+	"github.com/moby/moby/v2/daemon/internal/extensionconfig"
+
 	containernamegeneratorpb "github.com/moby/moby/v2/extpoints/containernamegenerator/v0/protogen"
+	daemonconfigpb "github.com/moby/moby/v2/extpoints/daemonconfig/v0/protogen"
 	servicenamegeneratorpb "github.com/moby/moby/v2/extpoints/servicenamegenerator/v0/protogen"
 	namesgeneratorlegacy "github.com/moby/moby/v2/internal/namesgenerator/legacy"
 )
 
+// builtinExtensions lists in-tree extensions that should be available in the
+// engine by default.
+var builtinExtensions = []extensions.Extension{
+	namesgeneratorlegacy.Extension,
+}
+
+// daemonExtensions declares extensions that need daemon-owned state.
+// Ordinary builtin definitions obtain their bootstrap settings through points.
+func (daemon *Daemon) daemonExtensions() []extensions.Extension {
+	cfg := daemon.Config()
+	return []extensions.Extension{
+		extensionconfig.New(&cfg),
+	}
+}
+
 // clientProviders lists generated client wiring for points that launched
-// extensions may provide. Socket exposure is resolved locally and is not listed.
+// extensions may provide.
+//
+// A point that's simply exposed as a service by an extension DOES NOT need to
+// be in this list.
+// This list only contains points that the daemon calls directly.
 func clientProviders() []clientpoint.Registration {
 	return []clientpoint.Registration{
 		containernamegeneratorpb.ClientPoint,
@@ -18,9 +40,11 @@ func clientProviders() []clientpoint.Registration {
 	}
 }
 
-// builtinExtensions returns the in-process extensions selected by daemon config.
-func builtinExtensions(*config.Config) []extensions.Extension {
-	return []extensions.Extension{
-		namesgeneratorlegacy.Extension,
+// dependencyProviders lists points that external extensions may call back
+// into.
+// Points not in this list will not be able to used as dependencies.
+func dependencyProviders() []serverpoint.Registration {
+	return []serverpoint.Registration{
+		daemonconfigpb.ServerPoint,
 	}
 }

daemon/internal/extensionconfig/config.go

@@ -0,0 +1,28 @@
+// Package extensionconfig provides the daemon configuration snapshot to extensions.
+package extensionconfig
+
+import (
+	"context"
+
+	"github.com/moby/extensions"
+	"github.com/moby/moby/v2/daemon/config"
+	daemonconfigv0 "github.com/moby/moby/v2/extpoints/daemonconfig/v0"
+)
+
+// New declares a config provider with an immutable persistent-root snapshot.
+func New(cfg *config.Config) extensions.Extension {
+	return extensions.New(extensions.Declaration{
+		ID: "org.mobyproject.daemon.config.v0",
+		Providers: []extensions.Provider{
+			daemonconfigv0.Point.Provide(snapshot{rootDir: cfg.Root}),
+		},
+	})
+}
+
+type snapshot struct {
+	rootDir string
+}
+
+func (s snapshot) Get(context.Context, *daemonconfigv0.GetRequest) (*daemonconfigv0.GetResponse, error) {
+	return &daemonconfigv0.GetResponse{RootDir: s.rootDir}, nil
+}

extpoints/daemonconfig/v0/daemon_config.proto

@@ -0,0 +1,18 @@
+// Code generated by mobyextgen. DO NOT EDIT.
+
+syntax = "proto3";
+
+package org.mobyproject.extension.daemon.config.v0;
+
+option go_package = "github.com/moby/moby/v2/extpoints/daemonconfig/v0/protogen";
+
+service DaemonConfig {
+  rpc Get(GetRequest) returns (GetResponse);
+}
+
+message GetRequest {
+}
+
+message GetResponse {
+  string root_dir = 1;
+}

extpoints/daemonconfig/v0/daemonconfig.go

@@ -0,0 +1,34 @@
+//go:generate go tool mobyextgen
+
+// Package daemonconfigv0 defines the read-only daemon configuration snapshot
+// available to Moby extensions.
+package daemonconfigv0
+
+import (
+	"context"
+
+	"github.com/moby/extensions"
+)
+
+// DaemonConfig provides an immutable snapshot of extension bootstrap settings.
+// It does not expose the daemon's full configuration or a generic lookup API.
+type DaemonConfig interface {
+	// Get returns a fresh copy of the snapshot.
+	Get(ctx context.Context, req *GetRequest) (*GetResponse, error)
+}
+
+// Point is single-cardinality for the daemon configuration snapshot.
+// The daemon registers its builtin provider for extension dependencies,
+// including out-of-process extensions, but does not publish it on the public
+// daemon socket.
+var Point = extensions.DefineSinglePoint[DaemonConfig]("org.mobyproject.extension.daemon.config.v0")
+
+// GetRequest requests the daemon configuration snapshot.
+type GetRequest struct{}
+
+// GetResponse contains the immutable extension bootstrap settings.
+type GetResponse struct {
+	// RootDir is the absolute path to the daemon's persistent data root,
+	// not its execution root.
+	RootDir string `pb:"1"`
+}

extpoints/daemonconfig/v0/protogen/daemon_config.pb.go

@@ -0,0 +1,165 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.36.12
+// 	protoc        (unknown)
+// source: extpoints/daemonconfig/v0/daemon_config.proto
+
+package protogen
+
+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 GetRequest struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *GetRequest) Reset() {
+	*x = GetRequest{}
+	mi := &file_extpoints_daemonconfig_v0_daemon_config_proto_msgTypes[0]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *GetRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*GetRequest) ProtoMessage() {}
+
+func (x *GetRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_extpoints_daemonconfig_v0_daemon_config_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 GetRequest.ProtoReflect.Descriptor instead.
+func (*GetRequest) Descriptor() ([]byte, []int) {
+	return file_extpoints_daemonconfig_v0_daemon_config_proto_rawDescGZIP(), []int{0}
+}
+
+type GetResponse struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	RootDir       string                 `protobuf:"bytes,1,opt,name=root_dir,json=rootDir,proto3" json:"root_dir,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *GetResponse) Reset() {
+	*x = GetResponse{}
+	mi := &file_extpoints_daemonconfig_v0_daemon_config_proto_msgTypes[1]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *GetResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*GetResponse) ProtoMessage() {}
+
+func (x *GetResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_extpoints_daemonconfig_v0_daemon_config_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 GetResponse.ProtoReflect.Descriptor instead.
+func (*GetResponse) Descriptor() ([]byte, []int) {
+	return file_extpoints_daemonconfig_v0_daemon_config_proto_rawDescGZIP(), []int{1}
+}
+
+func (x *GetResponse) GetRootDir() string {
+	if x != nil {
+		return x.RootDir
+	}
+	return ""
+}
+
+var File_extpoints_daemonconfig_v0_daemon_config_proto protoreflect.FileDescriptor
+
+const file_extpoints_daemonconfig_v0_daemon_config_proto_rawDesc = "" +
+	"\n" +
+	"-extpoints/daemonconfig/v0/daemon_config.proto\x12*org.mobyproject.extension.daemon.config.v0\"\f\n" +
+	"\n" +
+	"GetRequest\"(\n" +
+	"\vGetResponse\x12\x19\n" +
+	"\broot_dir\x18\x01 \x01(\tR\arootDir2\x86\x01\n" +
+	"\fDaemonConfig\x12v\n" +
+	"\x03Get\x126.org.mobyproject.extension.daemon.config.v0.GetRequest\x1a7.org.mobyproject.extension.daemon.config.v0.GetResponseB<Z:github.com/moby/moby/v2/extpoints/daemonconfig/v0/protogenb\x06proto3"
+
+var (
+	file_extpoints_daemonconfig_v0_daemon_config_proto_rawDescOnce sync.Once
+	file_extpoints_daemonconfig_v0_daemon_config_proto_rawDescData []byte
+)
+
+func file_extpoints_daemonconfig_v0_daemon_config_proto_rawDescGZIP() []byte {
+	file_extpoints_daemonconfig_v0_daemon_config_proto_rawDescOnce.Do(func() {
+		file_extpoints_daemonconfig_v0_daemon_config_proto_rawDescData = protoimpl.X.CompressGZIP(unsafe.Slice(unsafe.StringData(file_extpoints_daemonconfig_v0_daemon_config_proto_rawDesc), len(file_extpoints_daemonconfig_v0_daemon_config_proto_rawDesc)))
+	})
+	return file_extpoints_daemonconfig_v0_daemon_config_proto_rawDescData
+}
+
+var file_extpoints_daemonconfig_v0_daemon_config_proto_msgTypes = make([]protoimpl.MessageInfo, 2)
+var file_extpoints_daemonconfig_v0_daemon_config_proto_goTypes = []any{
+	(*GetRequest)(nil),  // 0: org.mobyproject.extension.daemon.config.v0.GetRequest
+	(*GetResponse)(nil), // 1: org.mobyproject.extension.daemon.config.v0.GetResponse
+}
+var file_extpoints_daemonconfig_v0_daemon_config_proto_depIdxs = []int32{
+	0, // 0: org.mobyproject.extension.daemon.config.v0.DaemonConfig.Get:input_type -> org.mobyproject.extension.daemon.config.v0.GetRequest
+	1, // 1: org.mobyproject.extension.daemon.config.v0.DaemonConfig.Get:output_type -> org.mobyproject.extension.daemon.config.v0.GetResponse
+	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_extpoints_daemonconfig_v0_daemon_config_proto_init() }
+func file_extpoints_daemonconfig_v0_daemon_config_proto_init() {
+	if File_extpoints_daemonconfig_v0_daemon_config_proto != nil {
+		return
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeFor[x]().PkgPath(),
+			RawDescriptor: unsafe.Slice(unsafe.StringData(file_extpoints_daemonconfig_v0_daemon_config_proto_rawDesc), len(file_extpoints_daemonconfig_v0_daemon_config_proto_rawDesc)),
+			NumEnums:      0,
+			NumMessages:   2,
+			NumExtensions: 0,
+			NumServices:   1,
+		},
+		GoTypes:           file_extpoints_daemonconfig_v0_daemon_config_proto_goTypes,
+		DependencyIndexes: file_extpoints_daemonconfig_v0_daemon_config_proto_depIdxs,
+		MessageInfos:      file_extpoints_daemonconfig_v0_daemon_config_proto_msgTypes,
+	}.Build()
+	File_extpoints_daemonconfig_v0_daemon_config_proto = out.File
+	file_extpoints_daemonconfig_v0_daemon_config_proto_goTypes = nil
+	file_extpoints_daemonconfig_v0_daemon_config_proto_depIdxs = nil
+}

extpoints/daemonconfig/v0/protogen/wire.gen.go

@@ -0,0 +1,156 @@
+// Code generated by mobyextgen. DO NOT EDIT.
+package protogen
+
+import (
+	context "context"
+	extensions "github.com/moby/extensions"
+	clientpoint "github.com/moby/extensions/clientpoint"
+	serverpoint "github.com/moby/extensions/serverpoint"
+	daemonconfigv0 "github.com/moby/moby/v2/extpoints/daemonconfig/v0"
+	grpc "google.golang.org/grpc"
+)
+
+// serviceName is the point's fully-qualified gRPC service name.
+const serviceName = "org.mobyproject.extension.daemon.config.v0.DaemonConfig"
+
+const (
+	methodGet = "/" + serviceName + "/Get"
+)
+
+// DaemonConfigServer is the server side of the point's gRPC service. It is the
+// proto-level shape of the point, not the point's Go interface: a contract
+// method returning a bare error returns an empty response message here.
+type DaemonConfigServer interface {
+	Get(context.Context, *GetRequest) (*GetResponse, error)
+}
+
+// serviceDesc describes the point's gRPC service to a server. HandlerType is
+// what a registrar type-checks an implementation against, so registering the
+// wrong provider for this point is caught at registration.
+var serviceDesc = grpc.ServiceDesc{
+	ServiceName: serviceName,
+	HandlerType: (*DaemonConfigServer)(nil),
+	Metadata:    "extpoints/daemonconfig/v0/daemon_config.proto",
+	Methods: []grpc.MethodDesc{
+		{MethodName: "Get", Handler: handleGet},
+	},
+}
+
+func handleGet(srv any, ctx context.Context, dec func(any) error, interceptor grpc.UnaryServerInterceptor) (any, error) {
+	in := new(GetRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(DaemonConfigServer).Get(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{Server: srv, FullMethod: methodGet}
+	return interceptor(ctx, in, info, func(ctx context.Context, req any) (any, error) {
+		return srv.(DaemonConfigServer).Get(ctx, req.(*GetRequest))
+	})
+}
+
+// DaemonConfigClient calls the point's gRPC service. It is exported so a client
+// outside the framework - one calling a service an extension publishes on the
+// API socket - can reach it with a plain gRPC client.
+type DaemonConfigClient interface {
+	Get(ctx context.Context, in *GetRequest, opts ...grpc.CallOption) (*GetResponse, error)
+}
+
+// NewDaemonConfigClient returns a client for the point's gRPC service on cc.
+func NewDaemonConfigClient(cc grpc.ClientConnInterface) DaemonConfigClient {
+	return &serviceClient{cc: cc}
+}
+
+type serviceClient struct{ cc grpc.ClientConnInterface }
+
+func (c *serviceClient) Get(ctx context.Context, in *GetRequest, opts ...grpc.CallOption) (*GetResponse, error) {
+	out := new(GetResponse)
+	if err := c.cc.Invoke(ctx, methodGet, in, out, append([]grpc.CallOption{grpc.StaticMethod()}, opts...)...); err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// ServerPoint serves the DaemonConfig point: it registers the point's gRPC service for
+// a provider with an SDK server. A binary passes it to (*sdk.Server).Register.
+var ServerPoint = serverpoint.Registration{
+	Point: daemonconfigv0.Point.ID(),
+	Register: func(r grpc.ServiceRegistrar, impl any) {
+		r.RegisterService(&serviceDesc, &grpcServer{impl: impl.(daemonconfigv0.DaemonConfig)})
+	},
+}
+
+// ClientProvider builds a broker provider for the DaemonConfig point from an
+// out-of-process gRPC connection.
+func ClientProvider(conn grpc.ClientConnInterface) extensions.Provider {
+	return daemonconfigv0.Point.Provide(NewClient(conn))
+}
+
+// ClientPoint registers ClientProvider for the DaemonConfig point with a host.
+// Single carries the contract's cardinality: the point admits one provider.
+var ClientPoint = clientpoint.Registration{Point: daemonconfigv0.Point.ID(), Provider: ClientProvider, Single: true}
+
+// NewClient returns a daemonconfigv0.DaemonConfig that calls the DaemonConfig point over conn.
+func NewClient(conn grpc.ClientConnInterface) daemonconfigv0.DaemonConfig {
+	return &grpcClient{client: NewDaemonConfigClient(conn)}
+}
+
+// grpcServer serves an implementation of the contract's Go interface.
+type grpcServer struct {
+	impl daemonconfigv0.DaemonConfig
+}
+
+func (s *grpcServer) Get(ctx context.Context, req *GetRequest) (*GetResponse, error) {
+	resp, err := s.impl.Get(ctx, getRequestFromProto(req))
+	if err != nil {
+		return nil, err
+	}
+	return getResponseToProto(resp), nil
+}
+
+type grpcClient struct {
+	client DaemonConfigClient
+}
+
+func (c *grpcClient) Get(ctx context.Context, req *daemonconfigv0.GetRequest) (*daemonconfigv0.GetResponse, error) {
+	resp, err := c.client.Get(ctx, getRequestToProto(req))
+	if err != nil {
+		return nil, err
+	}
+	return getResponseFromProto(resp), nil
+}
+
+func getRequestToProto(in *daemonconfigv0.GetRequest) *GetRequest {
+	if in == nil {
+		return nil
+	}
+	out := &GetRequest{}
+	return out
+}
+
+func getRequestFromProto(in *GetRequest) *daemonconfigv0.GetRequest {
+	if in == nil {
+		return nil
+	}
+	out := &daemonconfigv0.GetRequest{}
+	return out
+}
+
+func getResponseToProto(in *daemonconfigv0.GetResponse) *GetResponse {
+	if in == nil {
+		return nil
+	}
+	out := &GetResponse{}
+	out.RootDir = in.RootDir
+	return out
+}
+
+func getResponseFromProto(in *GetResponse) *daemonconfigv0.GetResponse {
+	if in == nil {
+		return nil
+	}
+	out := &daemonconfigv0.GetResponse{}
+	out.RootDir = in.GetRootDir()
+	return out
+}