Generalize the plugin package

Remove containerd specific parts of the plugin package to prepare its
move out of the main repository. Separate the plugin registration
singleton into a separate package.

Separating out the plugin package and registration makes it easier to
implement external plugins without creating a dependency loop.

Signed-off-by: Derek McGowan <derek@mcg.dev>

services/containers/local.go

@@ -27,6 +27,7 @@ import (
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -38,7 +39,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.ContainersService,
 		Requires: []plugin.Type{

services/containers/service.go

@@ -23,6 +23,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/containers/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -30,7 +31,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "containers",
 		Requires: []plugin.Type{

services/content/service.go

@@ -21,13 +21,14 @@ import (
 
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 	"github.com/containerd/containerd/services/content/contentserver"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "content",
 		Requires: []plugin.Type{

services/content/store.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 	digest "github.com/opencontainers/go-digest"
@@ -36,7 +37,7 @@ type store struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.ContentService,
 		Requires: []plugin.Type{

services/diff/local.go

@@ -26,6 +26,7 @@ import (
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/oci"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 	"github.com/containerd/typeurl/v2"
@@ -49,7 +50,7 @@ type differ interface {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.DiffService,
 		Requires: []plugin.Type{

services/diff/service.go

@@ -22,13 +22,14 @@ import (
 
 	diffapi "github.com/containerd/containerd/api/services/diff/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 	"google.golang.org/grpc"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "diff",
 		Requires: []plugin.Type{

services/events/service.go

@@ -26,6 +26,7 @@ import (
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/events/exchange"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	ptypes "github.com/containerd/containerd/protobuf/types"
@@ -34,7 +35,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "events",
 		Requires: []plugin.Type{

services/healthcheck/service.go

@@ -18,6 +18,7 @@ package healthcheck
 
 import (
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 
 	"google.golang.org/grpc"
@@ -30,7 +31,7 @@ type service struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "healthcheck",
 		InitFn: func(*plugin.InitContext) (interface{}, error) {

services/images/local.go

@@ -28,6 +28,7 @@ import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/pkg/epoch"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -38,7 +39,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.ImagesService,
 		Requires: []plugin.Type{

services/images/service.go

@@ -22,6 +22,7 @@ import (
 
 	imagesapi "github.com/containerd/containerd/api/services/images/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -29,7 +30,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "images",
 		Requires: []plugin.Type{

services/introspection/local.go

@@ -28,6 +28,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/filters"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -39,7 +40,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:     plugins.ServicePlugin,
 		ID:       services.IntrospectionService,
 		Requires: []plugin.Type{},
@@ -47,7 +48,7 @@ func init() {
 			// this service fetches all plugins through the plugin set of the plugin context
 			return &Local{
 				plugins: ic.Plugins(),
-				root:    ic.Root,
+				root:    ic.Properties[plugins.PropertyRootDir],
 			}, nil
 		},
 	})

services/introspection/service.go

@@ -22,6 +22,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/introspection/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -29,7 +30,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:     plugins.GRPCPlugin,
 		ID:       "introspection",
 		Requires: []plugin.Type{plugins.ServicePlugin},
@@ -52,7 +53,7 @@ func init() {
 			if !ok {
 				return nil, errors.New("could not create a local client for introspection service")
 			}
-			localClient.UpdateLocal(ic.Root)
+			localClient.UpdateLocal(ic.Properties[plugins.PropertyRootDir])
 
 			return &server{
 				local: localClient,

services/leases/service.go

@@ -23,6 +23,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/leases"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	ptypes "github.com/containerd/containerd/protobuf/types"
@@ -30,7 +31,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "leases",
 		Requires: []plugin.Type{

services/namespaces/local.go

@@ -27,6 +27,7 @@ import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/namespaces"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -37,7 +38,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.NamespacesService,
 		Requires: []plugin.Type{

services/namespaces/service.go

@@ -22,6 +22,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/namespaces/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -29,7 +30,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "namespaces",
 		Requires: []plugin.Type{

services/opt/service.go

@@ -22,6 +22,7 @@ import (
 	"path/filepath"
 
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
@@ -32,7 +33,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.InternalPlugin,
 		ID:   "opt",
 		Config: &Config{

services/sandbox/controller_service.go

@@ -27,6 +27,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	"github.com/containerd/containerd/sandbox"
@@ -34,7 +35,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "sandbox-controllers",
 		Requires: []plugin.Type{

services/sandbox/store_service.go

@@ -25,13 +25,14 @@ import (
 	"github.com/containerd/containerd/api/types"
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/sandbox"
 	"github.com/containerd/log"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "sandboxes",
 		Requires: []plugin.Type{

services/server/config/config.go

@@ -239,11 +239,10 @@ type ProxyPlugin struct {
 }
 
 // Decode unmarshals a plugin specific configuration by plugin id
-func (c *Config) Decode(ctx context.Context, p *plugin.Registration) (interface{}, error) {
-	id := p.URI()
+func (c *Config) Decode(ctx context.Context, id string, config interface{}) (interface{}, error) {
 	data, ok := c.Plugins[id]
 	if !ok {
-		return p.Config, nil
+		return config, nil
 	}
 
 	b, err := toml.Marshal(data)
@@ -251,7 +250,7 @@ func (c *Config) Decode(ctx context.Context, p *plugin.Registration) (interface{
 		return nil, err
 	}
 
-	if err := toml.NewDecoder(bytes.NewReader(b)).DisallowUnknownFields().Decode(p.Config); err != nil {
+	if err := toml.NewDecoder(bytes.NewReader(b)).DisallowUnknownFields().Decode(config); err != nil {
 		var serr *toml.StrictMissingError
 		if errors.As(err, &serr) {
 			for _, derr := range serr.Errors {
@@ -260,7 +259,7 @@ func (c *Config) Decode(ctx context.Context, p *plugin.Registration) (interface{
 					"key":    strings.Join(derr.Key(), " "),
 				}).WithError(err).Warn("Ignoring unknown key in TOML for plugin")
 			}
-			err = toml.Unmarshal(b, p.Config)
+			err = toml.Unmarshal(b, config)
 		}
 		if err != nil {
 			return nil, err
@@ -268,7 +267,7 @@ func (c *Config) Decode(ctx context.Context, p *plugin.Registration) (interface{
 
 	}
 
-	return p.Config, nil
+	return config, nil
 }
 
 // LoadConfig loads the containerd server config from the provided path

services/server/config/config_test.go

@@ -25,7 +25,6 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
-	"github.com/containerd/containerd/plugin"
 	"github.com/containerd/log/logtest"
 )
 
@@ -201,7 +200,7 @@ func TestDecodePlugin(t *testing.T) {
 	ctx := logtest.WithT(context.Background(), t)
 	data := `
 version = 2
-[plugins."io.containerd.runtime.v1.linux"]
+[plugins."io.containerd.runtime.v2.task"]
   shim_debug = true
 `
 
@@ -216,7 +215,7 @@ version = 2
 	assert.NoError(t, err)
 
 	pluginConfig := map[string]interface{}{}
-	_, err = out.Decode(ctx, &plugin.Registration{Type: "io.containerd.runtime.v1", ID: "linux", Config: &pluginConfig})
+	_, err = out.Decode(ctx, "io.containerd.runtime.v2.task", &pluginConfig)
 	assert.NoError(t, err)
 	assert.Equal(t, true, pluginConfig["shim_debug"])
 }
@@ -226,7 +225,7 @@ version = 2
 func TestDecodePluginInV1Config(t *testing.T) {
 	ctx := logtest.WithT(context.Background(), t)
 	data := `
-[plugins.linux]
+[plugins.task]
   shim_debug = true
 `
 
@@ -244,7 +243,7 @@ func TestDecodePluginInV1Config(t *testing.T) {
 	assert.Equal(t, 3, out.Version)
 
 	pluginConfig := map[string]interface{}{}
-	_, err = out.Decode(ctx, &plugin.Registration{Type: "io.containerd.runtime.v1", ID: "linux", Config: &pluginConfig})
+	_, err = out.Decode(ctx, "io.containerd.runtime.v2.task", &pluginConfig)
 	assert.NoError(t, err)
 	assert.Equal(t, true, pluginConfig["shim_debug"])
 }

services/server/server.go

@@ -46,6 +46,7 @@ import (
 	"github.com/containerd/containerd/pkg/timeout"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	srvconfig "github.com/containerd/containerd/services/server/config"
 	ssproxy "github.com/containerd/containerd/snapshots/proxy"
@@ -245,13 +246,14 @@ func New(ctx context.Context, config *srvconfig.Config) (*Server, error) {
 
 		initContext := plugin.NewContext(
 			ctx,
-			p,
 			initialized,
-			config.Root,
-			config.State,
+			map[string]string{
+				plugins.PropertyRootDir:      filepath.Join(config.Root, id),
+				plugins.PropertyStateDir:     filepath.Join(config.State, id),
+				plugins.PropertyGRPCAddress:  config.GRPC.Address,
+				plugins.PropertyTTRPCAddress: config.TTRPC.Address,
+			},
 		)
-		initContext.Address = config.GRPC.Address
-		initContext.TTRPCAddress = config.TTRPC.Address
 		initContext.RegisterReadiness = func() func() {
 			atomic.StoreInt32(&mustSucceed, 1)
 			return s.RegisterReadiness()
@@ -259,7 +261,7 @@ func New(ctx context.Context, config *srvconfig.Config) (*Server, error) {
 
 		// load the plugin specific configuration if it is provided
 		if p.Config != nil {
-			pc, err := config.Decode(ctx, p)
+			pc, err := config.Decode(ctx, id, p.Config)
 			if err != nil {
 				return nil, err
 			}
@@ -426,7 +428,7 @@ func (s *Server) Wait() {
 
 // LoadPlugins loads all plugins into containerd and generates an ordered graph
 // of all plugins.
-func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Registration, error) {
+func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]plugin.Registration, error) {
 	// load all plugins into containerd
 	path := config.PluginDir
 	if path == "" {
@@ -436,12 +438,13 @@ func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Regis
 		return nil, err
 	}
 	// load additional plugins that don't automatically register themselves
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ContentPlugin,
 		ID:   "content",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
-			ic.Meta.Exports["root"] = ic.Root
-			return local.NewStore(ic.Root)
+			root := ic.Properties[plugins.PropertyRootDir]
+			ic.Meta.Exports["root"] = root
+			return local.NewStore(root)
 		},
 	})
 
@@ -486,7 +489,7 @@ func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Regis
 			p = platforms.DefaultSpec()
 		}
 
-		plugin.Register(&plugin.Registration{
+		registry.Register(&plugin.Registration{
 			Type: t,
 			ID:   name,
 			InitFn: func(ic *plugin.InitContext) (interface{}, error) {
@@ -504,7 +507,7 @@ func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Regis
 
 	filter := srvconfig.V2DisabledFilter
 	// return the ordered graph for plugins
-	return plugin.Graph(filter(config.DisabledPlugins)), nil
+	return registry.Graph(filter(config.DisabledPlugins)), nil
 }
 
 type proxyClients struct {

services/server/server_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	srvconfig "github.com/containerd/containerd/services/server/config"
 	"github.com/stretchr/testify/assert"
 )
@@ -57,8 +58,8 @@ func TestCreateTopLevelDirectoriesWithEmptyRootPath(t *testing.T) {
 }
 
 func TestMigration(t *testing.T) {
-	plugin.Reset()
-	defer plugin.Reset()
+	registry.Reset()
+	defer registry.Reset()
 
 	version := srvconfig.CurrentConfigVersion - 1
 
@@ -67,7 +68,7 @@ func TestMigration(t *testing.T) {
 		NotMigrated string `toml:"notmigrated"`
 	}
 
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   "io.containerd.test",
 		ID:     "t1",
 		Config: &testConfig{},
@@ -86,7 +87,7 @@ func TestMigration(t *testing.T) {
 			return nil, nil
 		},
 	})
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: "io.containerd.new",
 		Requires: []plugin.Type{
 			"io.containerd.test", // Ensure this test runs second

services/snapshots/service.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -33,7 +34,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "snapshots",
 		Requires: []plugin.Type{

services/snapshots/snapshotters.go

@@ -19,12 +19,13 @@ package snapshots
 import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.SnapshotsService,
 		Requires: []plugin.Type{

services/streaming/service.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/pkg/streaming"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	ptypes "github.com/containerd/containerd/protobuf/types"
@@ -42,7 +43,7 @@ func init() {
 		panic(err)
 	}
 
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "streaming",
 		Requires: []plugin.Type{

services/tasks/local.go

@@ -19,6 +19,7 @@ package tasks
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -41,6 +42,7 @@ import (
 	"github.com/containerd/containerd/pkg/rdt"
 	"github.com/containerd/containerd/pkg/timeout"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	"github.com/containerd/containerd/protobuf/proto"
@@ -75,7 +77,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:     plugins.ServicePlugin,
 		ID:       services.TasksService,
 		Requires: tasksServiceRequires,
@@ -106,7 +108,7 @@ func initFunc(ic *plugin.InitContext) (interface{}, error) {
 
 	monitor, err := ic.Get(plugins.TaskMonitorPlugin)
 	if err != nil {
-		if !errdefs.IsNotFound(err) {
+		if !errors.Is(err, plugin.ErrPluginNotFound) {
 			return nil, err
 		}
 		monitor = runtime.NewNoopMonitor()

services/tasks/service.go

@@ -22,6 +22,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/tasks/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -33,7 +34,7 @@ var (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "tasks",
 		Requires: []plugin.Type{

services/transfer/service.go

@@ -26,6 +26,7 @@ import (
 	"github.com/containerd/containerd/pkg/transfer"
 	tplugins "github.com/containerd/containerd/pkg/transfer/plugins"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/log"
@@ -37,7 +38,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "transfer",
 		Requires: []plugin.Type{

services/version/service.go

@@ -21,6 +21,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/version/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	ctrdversion "github.com/containerd/containerd/version"
@@ -30,7 +31,7 @@ import (
 var _ api.VersionServer = &service{}
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.GRPCPlugin,
 		ID:     "version",
 		InitFn: initFunc,