Add ttrpc support to content proxy

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

client/client.go

@@ -27,7 +27,6 @@ import (
 	"time"
 
 	containersapi "github.com/containerd/containerd/v2/api/services/containers/v1"
-	contentapi "github.com/containerd/containerd/v2/api/services/content/v1"
 	diffapi "github.com/containerd/containerd/v2/api/services/diff/v1"
 	imagesapi "github.com/containerd/containerd/v2/api/services/images/v1"
 	introspectionapi "github.com/containerd/containerd/v2/api/services/introspection/v1"
@@ -622,7 +621,7 @@ func (c *Client) ContentStore() content.Store {
 	}
 	c.connMu.Lock()
 	defer c.connMu.Unlock()
-	return contentproxy.NewContentStore(contentapi.NewContentClient(c.conn))
+	return contentproxy.NewContentStore(c.conn)
 }
 
 // SnapshotService returns the underlying snapshotter for the provided snapshotter name

cmd/containerd/server/server.go

@@ -46,7 +46,6 @@ import (
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/credentials/insecure"
 
-	csapi "github.com/containerd/containerd/v2/api/services/content/v1"
 	diffapi "github.com/containerd/containerd/v2/api/services/diff/v1"
 	sbapi "github.com/containerd/containerd/v2/api/services/sandbox/v1"
 	ssapi "github.com/containerd/containerd/v2/api/services/snapshots/v1"
@@ -507,7 +506,7 @@ func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]plugin.Regist
 		case string(plugins.ContentPlugin), "content":
 			t = plugins.ContentPlugin
 			f = func(conn *grpc.ClientConn) interface{} {
-				return csproxy.NewContentStore(csapi.NewContentClient(conn))
+				return csproxy.NewContentStore(conn)
 			}
 		case string(plugins.SandboxControllerPlugin), "sandbox":
 			t = plugins.SandboxControllerPlugin

core/content/proxy/content_reader.go

@@ -27,7 +27,7 @@ type remoteReaderAt struct {
 	ctx    context.Context
 	digest digest.Digest
 	size   int64
-	client contentapi.ContentClient
+	client contentapi.TTRPCContentClient
 }
 
 func (ra *remoteReaderAt) Size() int64 {

core/content/proxy/content_store.go

@@ -18,6 +18,7 @@ package proxy
 
 import (
 	"context"
+	"fmt"
 	"io"
 
 	contentapi "github.com/containerd/containerd/v2/api/services/content/v1"
@@ -25,19 +26,41 @@ import (
 	"github.com/containerd/containerd/v2/protobuf"
 	protobuftypes "github.com/containerd/containerd/v2/protobuf/types"
 	"github.com/containerd/errdefs"
+	"github.com/containerd/ttrpc"
 	digest "github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"google.golang.org/grpc"
+	"google.golang.org/protobuf/types/known/emptypb"
 )
 
 type proxyContentStore struct {
-	client contentapi.ContentClient
+	// client is the rpc content client
+	// NOTE: ttrpc is used because it is the smaller interface shared with grpc
+	client contentapi.TTRPCContentClient
 }
 
 // NewContentStore returns a new content store which communicates over a GRPC
 // connection using the containerd content GRPC API.
-func NewContentStore(client contentapi.ContentClient) content.Store {
+func NewContentStore(client any) content.Store {
-	return &proxyContentStore{
+	switch c := client.(type) {
-		client: client,
+	case contentapi.ContentClient:
+		return &proxyContentStore{
+			client: convertClient{c},
+		}
+	case grpc.ClientConnInterface:
+		return &proxyContentStore{
+			client: convertClient{contentapi.NewContentClient(c)},
+		}
+	case contentapi.TTRPCContentClient:
+		return &proxyContentStore{
+			client: c,
+		}
+	case *ttrpc.Client:
+		return &proxyContentStore{
+			client: contentapi.NewTTRPCContentClient(c),
+		}
+	default:
+		panic(fmt.Errorf("unsupported content client %T: %w", client, errdefs.ErrNotImplemented))
 	}
 }
 
@@ -191,7 +214,7 @@ func (pcs *proxyContentStore) Abort(ctx context.Context, ref string) error {
 	return nil
 }
 
-func (pcs *proxyContentStore) negotiate(ctx context.Context, ref string, size int64, expected digest.Digest) (contentapi.Content_WriteClient, int64, error) {
+func (pcs *proxyContentStore) negotiate(ctx context.Context, ref string, size int64, expected digest.Digest) (contentapi.TTRPCContent_WriteClient, int64, error) {
 	wrclient, err := pcs.client.Write(ctx)
 	if err != nil {
 		return nil, 0, err
@@ -214,6 +237,70 @@ func (pcs *proxyContentStore) negotiate(ctx context.Context, ref string, size in
 	return wrclient, resp.Offset, nil
 }
 
+type convertClient struct {
+	contentapi.ContentClient
+}
+
+func (c convertClient) Info(ctx context.Context, req *contentapi.InfoRequest) (*contentapi.InfoResponse, error) {
+	return c.ContentClient.Info(ctx, req)
+}
+
+func (c convertClient) Update(ctx context.Context, req *contentapi.UpdateRequest) (*contentapi.UpdateResponse, error) {
+	return c.ContentClient.Update(ctx, req)
+}
+
+type convertListClient struct {
+	contentapi.Content_ListClient
+}
+
+func (c convertClient) List(ctx context.Context, req *contentapi.ListContentRequest) (contentapi.TTRPCContent_ListClient, error) {
+	lc, err := c.ContentClient.List(ctx, req)
+	if lc == nil {
+		return nil, err
+	}
+	return convertListClient{lc}, err
+}
+
+func (c convertClient) Delete(ctx context.Context, req *contentapi.DeleteContentRequest) (*emptypb.Empty, error) {
+	return c.ContentClient.Delete(ctx, req)
+}
+
+type convertReadClient struct {
+	contentapi.Content_ReadClient
+}
+
+func (c convertClient) Read(ctx context.Context, req *contentapi.ReadContentRequest) (contentapi.TTRPCContent_ReadClient, error) {
+	rc, err := c.ContentClient.Read(ctx, req)
+	if rc == nil {
+		return nil, err
+	}
+	return convertReadClient{rc}, err
+}
+
+func (c convertClient) Status(ctx context.Context, req *contentapi.StatusRequest) (*contentapi.StatusResponse, error) {
+	return c.ContentClient.Status(ctx, req)
+}
+
+func (c convertClient) ListStatuses(ctx context.Context, req *contentapi.ListStatusesRequest) (*contentapi.ListStatusesResponse, error) {
+	return c.ContentClient.ListStatuses(ctx, req)
+}
+
+type convertWriteClient struct {
+	contentapi.Content_WriteClient
+}
+
+func (c convertClient) Write(ctx context.Context) (contentapi.TTRPCContent_WriteClient, error) {
+	wc, err := c.ContentClient.Write(ctx)
+	if wc == nil {
+		return nil, err
+	}
+	return convertWriteClient{wc}, err
+}
+
+func (c convertClient) Abort(ctx context.Context, req *contentapi.AbortRequest) (*emptypb.Empty, error) {
+	return c.ContentClient.Abort(ctx, req)
+}
+
 func infoToGRPC(info *content.Info) *contentapi.Info {
 	return &contentapi.Info{
 		Digest:    info.Digest.String(),

core/content/proxy/content_writer.go

@@ -30,7 +30,7 @@ import (
 
 type remoteWriter struct {
 	ref    string
-	client contentapi.Content_WriteClient
+	client contentapi.TTRPCContent_WriteClient
 	offset int64
 	digest digest.Digest
 }