Move client to subpackage

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

client/transfer.go

@@ -0,0 +1,109 @@
+/*
+   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 client
+
+import (
+	"context"
+	"errors"
+	"io"
+
+	streamingapi "github.com/containerd/containerd/v2/api/services/streaming/v1"
+	transferapi "github.com/containerd/containerd/v2/api/services/transfer/v1"
+	"github.com/containerd/containerd/v2/errdefs"
+	"github.com/containerd/containerd/v2/pkg/streaming"
+	"github.com/containerd/containerd/v2/pkg/transfer"
+	"github.com/containerd/containerd/v2/pkg/transfer/proxy"
+	"github.com/containerd/containerd/v2/protobuf"
+	"github.com/containerd/typeurl/v2"
+)
+
+func (c *Client) Transfer(ctx context.Context, src interface{}, dest interface{}, opts ...transfer.Opt) error {
+	ctx, done, err := c.WithLease(ctx)
+	if err != nil {
+		return err
+	}
+	defer done(ctx)
+
+	return proxy.NewTransferrer(transferapi.NewTransferClient(c.conn), c.streamCreator()).Transfer(ctx, src, dest, opts...)
+}
+
+func (c *Client) streamCreator() streaming.StreamCreator {
+	return &streamCreator{
+		client: streamingapi.NewStreamingClient(c.conn),
+	}
+}
+
+type streamCreator struct {
+	client streamingapi.StreamingClient
+}
+
+func (sc *streamCreator) Create(ctx context.Context, id string) (streaming.Stream, error) {
+	stream, err := sc.client.Stream(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	a, err := typeurl.MarshalAny(&streamingapi.StreamInit{
+		ID: id,
+	})
+	if err != nil {
+		return nil, err
+	}
+	err = stream.Send(protobuf.FromAny(a))
+	if err != nil {
+		if !errors.Is(err, io.EOF) {
+			err = errdefs.FromGRPC(err)
+		}
+		return nil, err
+	}
+
+	// Receive an ack that stream is init and ready
+	if _, err = stream.Recv(); err != nil {
+		if !errors.Is(err, io.EOF) {
+			err = errdefs.FromGRPC(err)
+		}
+		return nil, err
+	}
+
+	return &clientStream{
+		s: stream,
+	}, nil
+}
+
+type clientStream struct {
+	s streamingapi.Streaming_StreamClient
+}
+
+func (cs *clientStream) Send(a typeurl.Any) (err error) {
+	err = cs.s.Send(protobuf.FromAny(a))
+	if !errors.Is(err, io.EOF) {
+		err = errdefs.FromGRPC(err)
+	}
+	return
+}
+
+func (cs *clientStream) Recv() (a typeurl.Any, err error) {
+	a, err = cs.s.Recv()
+	if !errors.Is(err, io.EOF) {
+		err = errdefs.FromGRPC(err)
+	}
+	return
+}
+
+func (cs *clientStream) Close() error {
+	return cs.s.CloseSend()
+}