Register local content plugin from separate package

Update the local content plugin to register itself in a consistent way
as other plugins. This also allows the separate package to define its
own configuration more cleanly.

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

cmd/containerd/builtins/builtins.go

@@ -19,6 +19,7 @@ package builtins
 // register containerd builtins here
 import (
 	_ "github.com/containerd/containerd/v2/core/runtime/v2"
+	_ "github.com/containerd/containerd/v2/plugins/content/local/plugin"
 	_ "github.com/containerd/containerd/v2/plugins/events"
 	_ "github.com/containerd/containerd/v2/plugins/gc"
 	_ "github.com/containerd/containerd/v2/plugins/imageverifier"

cmd/containerd/server/server.go

@@ -49,6 +49,11 @@ import (
 	diffapi "github.com/containerd/containerd/api/services/diff/v1"
 	sbapi "github.com/containerd/containerd/api/services/sandbox/v1"
 	ssapi "github.com/containerd/containerd/api/services/snapshots/v1"
+	"github.com/containerd/platforms"
+	"github.com/containerd/plugin"
+	"github.com/containerd/plugin/dynamic"
+	"github.com/containerd/plugin/registry"
+
 	srvconfig "github.com/containerd/containerd/v2/cmd/containerd/server/config"
 	csproxy "github.com/containerd/containerd/v2/core/content/proxy"
 	"github.com/containerd/containerd/v2/core/diff"
@@ -61,13 +66,8 @@ import (
 	"github.com/containerd/containerd/v2/pkg/sys"
 	"github.com/containerd/containerd/v2/pkg/timeout"
 	"github.com/containerd/containerd/v2/plugins"
-	"github.com/containerd/containerd/v2/plugins/content/local"
 	"github.com/containerd/containerd/v2/plugins/services/warning"
 	"github.com/containerd/containerd/v2/version"
-	"github.com/containerd/platforms"
-	"github.com/containerd/plugin"
-	"github.com/containerd/plugin/dynamic"
-	"github.com/containerd/plugin/registry"
 )
 
 // CreateTopLevelDirectories creates the top-level root and state directories.
@@ -482,16 +482,6 @@ func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]plugin.Regist
 		config.PluginDir = path //nolint:staticcheck
 		log.G(ctx).Warningf("loaded %d dynamic plugins. `go_plugin` is deprecated, please use `external plugins` instead", count)
 	}
-	// load additional plugins that don't automatically register themselves
-	registry.Register(&plugin.Registration{
-		Type: plugins.ContentPlugin,
-		ID:   "content",
-		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
-			root := ic.Properties[plugins.PropertyRootDir]
-			ic.Meta.Exports["root"] = root
-			return local.NewStore(root)
-		},
-	})
 
 	clients := &proxyClients{}
 	for name, pp := range config.ProxyPlugins {

integration/build_local_containerd_helper_test.go

@@ -36,6 +36,7 @@ import (
 
 	_ "github.com/containerd/containerd/api/types/runc/options"
 	_ "github.com/containerd/containerd/v2/core/runtime/v2"
+	_ "github.com/containerd/containerd/v2/plugins/content/local/plugin"
 	_ "github.com/containerd/containerd/v2/plugins/cri/images"
 	_ "github.com/containerd/containerd/v2/plugins/cri/runtime"
 	_ "github.com/containerd/containerd/v2/plugins/diff/walking/plugin"

plugins/content/local/plugin/plugin.go

@@ -0,0 +1,37 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package plugin
+
+import (
+	"github.com/containerd/plugin"
+	"github.com/containerd/plugin/registry"
+
+	"github.com/containerd/containerd/v2/plugins"
+	"github.com/containerd/containerd/v2/plugins/content/local"
+)
+
+func init() {
+	registry.Register(&plugin.Registration{
+		Type: plugins.ContentPlugin,
+		ID:   "content",
+		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
+			root := ic.Properties[plugins.PropertyRootDir]
+			ic.Meta.Exports["root"] = root
+			return local.NewStore(root)
+		},
+	})
+}