driver: add client method

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

Dockerfile

@@ -60,10 +60,6 @@ COPY ./hack/demo-env/tmux.conf /root/.tmux.conf
 COPY --from=dockerd-release /usr/local/bin /usr/local/bin
 COPY --from=docker-cli-build /go/src/github.com/docker/cli/build/docker /usr/local/bin
 
-# Temporary buildkitd binaries. To be removed.
-COPY --from=moby/buildkit /usr/bin/build* /usr/local/bin
-VOLUME /var/lib/buildkit
-
 WORKDIR /work
 COPY ./hack/demo-env/examples .
 COPY --from=binaries / /usr/local/bin/

commands/build.go

@@ -94,7 +94,7 @@ func runBuild(dockerCli command.Cli, in buildOptions) error {
 	}
 	opts.Exports = outputs
 
-	d, err := driver.GetDriver(ctx, "buildkit.default", nil, dockerCli.Client())
+	d, err := driver.GetDriver(ctx, "buildx-buildkit-default", nil, dockerCli.Client())
 	if err != nil {
 		return err
 	}

driver/docker/driver.go

@@ -4,18 +4,24 @@ import (
 	"context"
 	"io"
 	"io/ioutil"
+	"net"
+	"os"
+	"time"
 
 	"github.com/docker/docker/api/types"
 	dockertypes "github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/api/types/network"
 	dockerclient "github.com/docker/docker/client"
+	"github.com/docker/docker/pkg/stdcopy"
 	"github.com/moby/buildkit/client"
 	"github.com/pkg/errors"
 	"github.com/tonistiigi/buildx/driver"
 	"github.com/tonistiigi/buildx/util/progress"
 )
 
+var buildkitImage = "moby/buildkit:master" // TODO: make this verified and configuratble
+
 type Driver struct {
 	driver.InitConfig
 	version dockertypes.Version
@@ -30,13 +36,21 @@ func (d *Driver) Bootstrap(ctx context.Context, l progress.Logger) error {
 			}
 			return err
 		}
-		return d.start(ctx, sub)
+		return sub.Wrap("starting container "+d.Name, func() error {
+			if err := d.start(ctx, sub); err != nil {
+				return err
+			}
+			if err := d.wait(ctx); err != nil {
+				return err
+			}
+			return nil
+		})
 	})
 }
 
 func (d *Driver) create(ctx context.Context, l progress.SubLogger) error {
-	if err := l.Wrap("pulling image moby/buildkit", func() error {
-		rc, err := d.DockerAPI.ImageCreate(ctx, "moby/buildkit", types.ImageCreateOptions{})
+	if err := l.Wrap("pulling image "+buildkitImage, func() error {
+		rc, err := d.DockerAPI.ImageCreate(ctx, buildkitImage, types.ImageCreateOptions{})
 		if err != nil {
 			return err
 		}
@@ -47,7 +61,7 @@ func (d *Driver) create(ctx context.Context, l progress.SubLogger) error {
 	}
 	if err := l.Wrap("creating container "+d.Name, func() error {
 		_, err := d.DockerAPI.ContainerCreate(ctx, &container.Config{
-			Image: "moby/buildkit",
+			Image: buildkitImage,
 		}, &container.HostConfig{
 			Privileged: true,
 		}, &network.NetworkingConfig{}, d.Name)
@@ -57,6 +71,9 @@ func (d *Driver) create(ctx context.Context, l progress.SubLogger) error {
 		if err := d.start(ctx, l); err != nil {
 			return err
 		}
+		if err := d.wait(ctx); err != nil {
+			return err
+		}
 		return nil
 	}); err != nil {
 		return err
@@ -64,6 +81,68 @@ func (d *Driver) create(ctx context.Context, l progress.SubLogger) error {
 	return nil
 }
 
+func (d *Driver) wait(ctx context.Context) error {
+	try := 0
+	for {
+		if err := d.run(ctx, []string{"buildctl", "debug", "workers"}); err != nil {
+			if try > 10 {
+				return err
+			}
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			case <-time.After(time.Duration(100+try*20) * time.Millisecond):
+				try++
+				continue
+			}
+		}
+		return nil
+	}
+}
+
+func (d *Driver) exec(ctx context.Context, cmd []string) (string, net.Conn, error) {
+	execConfig := types.ExecConfig{
+		Cmd:          cmd,
+		AttachStdin:  true,
+		AttachStdout: true,
+		AttachStderr: true,
+	}
+	response, err := d.DockerAPI.ContainerExecCreate(ctx, d.Name, execConfig)
+	if err != nil {
+		return "", nil, err
+	}
+
+	execID := response.ID
+	if execID == "" {
+		return "", nil, errors.New("exec ID empty")
+	}
+
+	resp, err := d.DockerAPI.ContainerExecAttach(ctx, execID, types.ExecStartCheck{})
+	if err != nil {
+		return "", nil, err
+	}
+	return execID, resp.Conn, nil
+}
+
+func (d *Driver) run(ctx context.Context, cmd []string) error {
+	id, conn, err := d.exec(ctx, cmd)
+	if err != nil {
+		return err
+	}
+	if _, err := io.Copy(ioutil.Discard, conn); err != nil {
+		return err
+	}
+	conn.Close()
+	resp, err := d.DockerAPI.ContainerExecInspect(ctx, id)
+	if err != nil {
+		return err
+	}
+	if resp.ExitCode != 0 {
+		return errors.Errorf("exit code %d", resp.ExitCode)
+	}
+	return nil
+}
+
 func (d *Driver) start(ctx context.Context, l progress.SubLogger) error {
 	return d.DockerAPI.ContainerStart(ctx, d.Name, types.ContainerStartOptions{})
 }
@@ -99,5 +178,33 @@ func (d *Driver) Rm(ctx context.Context, force bool) error {
 }
 
 func (d *Driver) Client(ctx context.Context) (*client.Client, error) {
-	return nil, errors.Errorf("client not implemented for %T", d)
+	_, conn, err := d.exec(ctx, []string{"buildctl", "dial-stdio"})
+	if err != nil {
+		return nil, err
+	}
+
+	conn = demuxConn(conn)
+
+	return client.New(ctx, "", client.WithDialer(func(string, time.Duration) (net.Conn, error) {
+		return conn, nil
+	}))
+}
+
+func demuxConn(c net.Conn) net.Conn {
+	pr, pw := io.Pipe()
+	// TODO: rewrite parser with Reader() to avoid goroutine switch
+	go stdcopy.StdCopy(pw, os.Stdout, c)
+	return &demux{
+		Conn:   c,
+		Reader: pr,
+	}
+}
+
+type demux struct {
+	net.Conn
+	io.Reader
+}
+
+func (d *demux) Read(dt []byte) (int, error) {
+	return d.Reader.Read(dt)
 }