controller: move controllers out of commands into separate package

Signed-off-by: Justin Chadwell <me@jedevc.com>

controller/local/controller.go

@@ -0,0 +1,79 @@
+package local
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"github.com/containerd/console"
+	"github.com/docker/buildx/build"
+	cbuild "github.com/docker/buildx/controller/build"
+	"github.com/docker/buildx/controller/control"
+	controllerapi "github.com/docker/buildx/controller/pb"
+	"github.com/docker/cli/cli/command"
+)
+
+func NewLocalBuildxController(ctx context.Context, dockerCli command.Cli) control.BuildxController {
+	return &localController{
+		dockerCli: dockerCli,
+		ref:       "local",
+	}
+}
+
+type localController struct {
+	dockerCli command.Cli
+	ref       string
+	resultCtx *build.ResultContext
+}
+
+func (b *localController) Invoke(ctx context.Context, ref string, cfg controllerapi.ContainerConfig, ioIn io.ReadCloser, ioOut io.WriteCloser, ioErr io.WriteCloser) error {
+	if ref != b.ref {
+		return fmt.Errorf("unknown ref %q", ref)
+	}
+	if b.resultCtx == nil {
+		return fmt.Errorf("no build result is registered")
+	}
+	ccfg := build.ContainerConfig{
+		ResultCtx:  b.resultCtx,
+		Entrypoint: cfg.Entrypoint,
+		Cmd:        cfg.Cmd,
+		Env:        cfg.Env,
+		Tty:        cfg.Tty,
+		Stdin:      ioIn,
+		Stdout:     ioOut,
+		Stderr:     ioErr,
+	}
+	if !cfg.NoUser {
+		ccfg.User = &cfg.User
+	}
+	if !cfg.NoCwd {
+		ccfg.Cwd = &cfg.Cwd
+	}
+	return build.Invoke(ctx, ccfg)
+}
+
+func (b *localController) Build(ctx context.Context, options controllerapi.BuildOptions, in io.ReadCloser, w io.Writer, out console.File, progressMode string) (string, error) {
+	res, err := cbuild.RunBuild(ctx, b.dockerCli, options, in, progressMode, nil)
+	if err != nil {
+		return "", err
+	}
+	b.resultCtx = res
+	return b.ref, nil
+}
+
+func (b *localController) Kill(context.Context) error {
+	return nil // nop
+}
+
+func (b *localController) Close() error {
+	// TODO: cancel current build and invoke
+	return nil
+}
+
+func (b *localController) List(ctx context.Context) (res []string, _ error) {
+	return []string{b.ref}, nil
+}
+
+func (b *localController) Disconnect(ctx context.Context, key string) error {
+	return nil // nop
+}