monitor: breakpoint debugger on terminal and on IDEs (via DAP)

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>

build/build.go

@@ -677,6 +677,12 @@ type ContainerConfig struct {
 	Cwd        *string
 
 	Initial bool
+
+	SignalCh <-chan syscall.Signal
+	ResizeCh <-chan gateway.WinSize
+
+	Image           string
+	ResultMountPath string
 }
 
 // ResultContext is a build result with the client that built it.
@@ -748,6 +754,29 @@ func Invoke(ctx context.Context, cfg ContainerConfig) error {
 			containerCfg, processCfg = *ccfg, *pcfg
 		}
 
+		if img := cfg.Image; img != "" {
+			def, err := llb.Image(img).Marshal(ctx)
+			if err != nil {
+				return nil, err
+			}
+			r, err := c.Solve(ctx, gateway.SolveRequest{
+				Definition: def.ToPB(),
+			})
+			if err != nil {
+				return nil, err
+			}
+			for i := range containerCfg.Mounts {
+				containerCfg.Mounts[i].Dest = filepath.Join(cfg.ResultMountPath, containerCfg.Mounts[i].Dest)
+			}
+			containerCfg.Mounts = append([]gateway.Mount{
+				{
+					Dest:      "/",
+					MountType: pb.MountType_BIND,
+					Ref:       r.Ref,
+				},
+			}, containerCfg.Mounts...)
+		}
+
 		ctr, err := c.NewContainer(ctx, containerCfg)
 		if err != nil {
 			return nil, err
@@ -758,8 +787,34 @@ func Invoke(ctx context.Context, cfg ContainerConfig) error {
 		if err != nil {
 			return nil, errors.Errorf("failed to start container: %v", err)
 		}
+		signalCh := cfg.SignalCh
+		if signalCh == nil {
+			signalCh = make(chan syscall.Signal)
+		}
+		resizeCh := cfg.ResizeCh
+		if resizeCh == nil {
+			resizeCh = make(chan gateway.WinSize)
+		}
 		errCh := make(chan error)
 		doneCh := make(chan struct{})
+		go func() {
+			for {
+				select {
+				case s := <-signalCh:
+					if err := proc.Signal(ctx, s); err != nil {
+						logrus.Warnf("failed to send signal %v %v", s, err)
+					}
+				case w := <-resizeCh:
+					if err := proc.Resize(ctx, w); err != nil {
+						logrus.Warnf("failed to resize %v: %v", w, err)
+					}
+				case <-ctx.Done():
+					return
+				case <-doneCh:
+					return
+				}
+			}
+		}()
 		go func() {
 			defer close(doneCh)
 			if err := proc.Wait(); err != nil {
@@ -1016,7 +1071,7 @@ func Build(ctx context.Context, nodes []builder.Node, opt map[string]Options, do
 	return BuildWithResultHandler(ctx, nodes, opt, docker, configDir, w, nil)
 }
 
-func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[string]Options, docker *dockerutil.Client, configDir string, w progress.Writer, resultHandleFunc func(driverIndex int, rCtx *ResultContext)) (resp map[string]*client.SolveResponse, err error) {
+func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[string]Options, docker *dockerutil.Client, configDir string, w progress.Writer, resultHandleFunc func(driverIndex int, rCtx *ResultContext) error) (resp map[string]*client.SolveResponse, err error) {
 	if len(nodes) == 0 {
 		return nil, errors.Errorf("driver required for build")
 	}
@@ -1279,7 +1334,9 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 							}
 							results.Set(resultKey(dp.driverIndex, k), res)
 							if resultHandleFunc != nil {
-								resultHandleFunc(dp.driverIndex, &ResultContext{Client: cc, Res: res})
+								if err := resultHandleFunc(dp.driverIndex, &ResultContext{Client: cc, Res: res}); err != nil {
+									return nil, err
+								}
 							}
 							return res, nil
 						}

cmd/buildx/main.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"os"
 
-	"github.com/containerd/containerd/pkg/seed"
+	"github.com/containerd/containerd/pkg/seed" //nolint:staticcheck // Global math/rand seed is deprecated, but still used by external dependencies
 	"github.com/docker/buildx/commands"
 	"github.com/docker/buildx/version"
 	"github.com/docker/cli/cli"
@@ -28,6 +28,7 @@ import (
 )
 
 func init() {
+	//nolint:staticcheck // Global math/rand seed is deprecated, but still used by external dependencies
 	seed.WithTimeAndRand()
 	stack.SetVersionInfo(version.Version, version.Revision)
 }

commands/build.go

@@ -32,6 +32,7 @@ import (
 	"github.com/docker/docker/pkg/ioutils"
 	"github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
+	solverpb "github.com/moby/buildkit/solver/pb"
 	"github.com/moby/buildkit/util/appcontext"
 	"github.com/moby/buildkit/util/grpcerrors"
 	"github.com/pkg/errors"
@@ -500,6 +501,7 @@ func launchControllerAndRunBuild(dockerCli command.Cli, options buildOptions) er
 	}
 
 	var ref string
+	var def *solverpb.Definition
 	var retErr error
 	f := ioset.NewSingleForwarder()
 	f.SetReader(os.Stdin)
@@ -518,12 +520,20 @@ func launchControllerAndRunBuild(dockerCli command.Cli, options buildOptions) er
 			}
 		}
 
+		if options.invoke == "debug-step" {
+			// Special mode where we don't get the result but get only the build definition.
+			// In this mode, Build() doesn't perform the build therefore always fails.
+			// The error returned by Build() contains *pb.Definition wrapped with *controllererror.BuildError.
+			opts.Debug = true
+		}
+
 		var resp *client.SolveResponse
-		ref, resp, err = c.Build(ctx, opts, pr, os.Stdout, os.Stderr, progress)
+		ref, resp, def, err = c.Build(ctx, opts, pr, os.Stdout, os.Stderr, progress)
 		if err != nil {
 			var be *controllererrors.BuildError
 			if errors.As(err, &be) {
 				ref = be.Ref
+				def = be.Definition
 				retErr = err
 				// We can proceed to monitor
 			} else {
@@ -564,7 +574,7 @@ func launchControllerAndRunBuild(dockerCli command.Cli, options buildOptions) er
 			}
 			return errors.Errorf("failed to configure terminal: %v", err)
 		}
-		err = monitor.RunMonitor(ctx, ref, &opts, invokeConfig, c, progress, pr2, os.Stdout, os.Stderr)
+		err = monitor.RunMonitor(ctx, ref, def, &opts, invokeConfig, c, progress, pr2, os.Stdout, os.Stderr)
 		con.Reset()
 		if err := pw2.Close(); err != nil {
 			logrus.Debug("failed to close monitor stdin pipe reader")
@@ -577,12 +587,12 @@ func launchControllerAndRunBuild(dockerCli command.Cli, options buildOptions) er
 			logrus.Warnf("disconnect error: %v", err)
 		}
 	}
-	return nil
+	return retErr
 }
 
 func needsMonitor(invokeFlag string, retErr error) bool {
 	switch invokeFlag {
-	case "debug-shell":
+	case "debug-shell", "debug-step":
 		return true
 	case "on-error":
 		return retErr != nil
@@ -596,8 +606,7 @@ func parseInvokeConfig(invoke string) (cfg controllerapi.ContainerConfig, err er
 	switch invoke {
 	case "default", "debug-shell":
 		return cfg, nil
-	case "on-error":
-		// NOTE: we overwrite the command to run because the original one should fail on the failed step.
+	case "on-error", "debug-step":
 		// TODO: make this configurable.
 		cfg.Cmd = []string{"/bin/sh"}
 		return cfg, nil

commands/debug-shell.go

@@ -38,7 +38,7 @@ func debugShellCmd(dockerCli command.Cli) *cobra.Command {
 			if err := con.SetRaw(); err != nil {
 				return errors.Errorf("failed to configure terminal: %v", err)
 			}
-			err = monitor.RunMonitor(ctx, "", nil, controllerapi.ContainerConfig{
+			err = monitor.RunMonitor(ctx, "", nil, nil, controllerapi.ContainerConfig{
 				Tty: true,
 			}, c, progress, os.Stdin, os.Stdout, os.Stderr)
 			con.Reset()

commands/root.go

@@ -5,6 +5,7 @@ import (
 
 	imagetoolscmd "github.com/docker/buildx/commands/imagetools"
 	"github.com/docker/buildx/controller/remote"
+	"github.com/docker/buildx/monitor/dap"
 	"github.com/docker/buildx/util/logutil"
 	"github.com/docker/cli-docs-tool/annotation"
 	"github.com/docker/cli/cli"
@@ -91,6 +92,7 @@ func addCommands(cmd *cobra.Command, dockerCli command.Cli) {
 		remote.AddControllerCommands(cmd, dockerCli)
 		addDebugShellCommand(cmd, dockerCli)
 	}
+	dap.AddDAPCommands(cmd, dockerCli) // hidden command; we need it for emacs DAP support
 }
 
 func rootFlags(options *rootOptions, flags *pflag.FlagSet) {

controller/build/build.go

@@ -175,15 +175,15 @@ func RunBuild(ctx context.Context, dockerCli command.Cli, in controllerapi.Build
 		return nil, nil, err
 	}
 
-	resp, res, err := buildTargets(ctx, dockerCli, b.NodeGroup, nodes, map[string]build.Options{defaultTargetName: opts}, progressMode, in.Opts.MetadataFile, statusChan)
+	resp, res, err := buildTargets(ctx, dockerCli, b.NodeGroup, nodes, map[string]build.Options{defaultTargetName: opts}, progressMode, in.Opts.MetadataFile, statusChan, in.Debug)
 	err = wrapBuildError(err, false)
 	if err != nil {
 		return nil, nil, err
 	}
 	return resp, res, nil
 }
 
-func buildTargets(ctx context.Context, dockerCli command.Cli, ng *store.NodeGroup, nodes []builder.Node, opts map[string]build.Options, progressMode string, metadataFile string, statusChan chan *client.SolveStatus) (*client.SolveResponse, *build.ResultContext, error) {
+func buildTargets(ctx context.Context, dockerCli command.Cli, ng *store.NodeGroup, nodes []builder.Node, opts map[string]build.Options, progressMode string, metadataFile string, statusChan chan *client.SolveStatus, debug bool) (*client.SolveResponse, *build.ResultContext, error) {
 	ctx2, cancel := context.WithCancel(context.TODO())
 	defer cancel()
 
@@ -198,12 +198,16 @@ func buildTargets(ctx context.Context, dockerCli command.Cli, ng *store.NodeGrou
 	var res *build.ResultContext
 	var mu sync.Mutex
 	var idx int
-	resp, err := build.BuildWithResultHandler(ctx, nodes, opts, dockerutil.NewClient(dockerCli), confutil.ConfigDir(dockerCli), progress.Tee(printer, statusChan), func(driverIndex int, gotRes *build.ResultContext) {
+	resp, err := build.BuildWithResultHandler(ctx, nodes, opts, dockerutil.NewClient(dockerCli), confutil.ConfigDir(dockerCli), progress.Tee(printer, statusChan), func(driverIndex int, gotRes *build.ResultContext) error {
 		mu.Lock()
 		defer mu.Unlock()
 		if res == nil || driverIndex < idx {
 			idx, res = driverIndex, gotRes
 		}
+		if debug {
+			return errors.Errorf("debug mode")
+		}
+		return nil
 	})
 	err1 := printer.Wait()
 	if err == nil {
@@ -386,6 +390,7 @@ func controllerUlimitOpt2DockerUlimit(u *controllerapi.UlimitOpt) *dockeropts.Ul
 
 type ResultContextError struct {
 	ResultContext *build.ResultContext
+	Definition    *solverpb.Definition
 	error
 }
 
@@ -408,7 +413,7 @@ func wrapResultContext(wErr error, res *build.ResultContext) error {
 		return wErr
 	}
 	res.Done()
-	return &ResultContextError{ResultContext: res2, error: wErr}
+	return &ResultContextError{ResultContext: res2, Definition: def, error: wErr}
 }
 
 func DefinitionFromResultContext(ctx context.Context, res *build.ResultContext) (*solverpb.Definition, error) {

controller/control/controller.go

@@ -3,24 +3,32 @@ package control
 import (
 	"context"
 	"io"
+	"syscall"
 
 	"github.com/containerd/console"
 	controllerapi "github.com/docker/buildx/controller/pb"
 	"github.com/moby/buildkit/client"
+	solverpb "github.com/moby/buildkit/solver/pb"
 )
 
 type BuildxController interface {
-	Build(ctx context.Context, options controllerapi.BuildOptions, in io.ReadCloser, w io.Writer, out console.File, progressMode string) (ref string, resp *client.SolveResponse, err error)
-	Invoke(ctx context.Context, ref string, options controllerapi.ContainerConfig, ioIn io.ReadCloser, ioOut io.WriteCloser, ioErr io.WriteCloser) (err error)
+	Invoke(ctx context.Context, ref string, options controllerapi.ContainerConfig, ioIn io.ReadCloser, ioOut io.WriteCloser, ioErr io.WriteCloser, signalCh <-chan syscall.Signal, resizeCh <-chan WinSize) error
+	Build(ctx context.Context, options controllerapi.BuildOptions, in io.ReadCloser, w io.Writer, out console.File, progressMode string) (ref string, resp *client.SolveResponse, def *solverpb.Definition, err error)
 	Kill(ctx context.Context) error
 	Close() error
 	List(ctx context.Context) (refs []string, _ error)
 	Disconnect(ctx context.Context, ref string) error
 	Inspect(ctx context.Context, ref string) (*controllerapi.InspectResponse, error)
+	Continue(ctx context.Context, ref string, def *solverpb.Definition, w io.Writer, out console.File, progressMode string) error
 }
 
 type ControlOptions struct {
 	ServerConfig string
 	Root         string
 	Detach       bool
 }
+
+type WinSize struct {
+	Rows uint32
+	Cols uint32
+}

controller/errdefs/build.go

@@ -1,7 +1,8 @@
 package errdefs
 
 import (
-	"github.com/containerd/typeurl"
+	"github.com/containerd/typeurl/v2"
+	"github.com/moby/buildkit/solver/pb"
 	"github.com/moby/buildkit/util/grpcerrors"
 )
 
@@ -22,11 +23,11 @@ func (e *BuildError) ToProto() grpcerrors.TypedErrorProto {
 	return &e.Build
 }
 
-func WrapBuild(err error, ref string) error {
+func WrapBuild(err error, ref string, def *pb.Definition) error {
 	if err == nil {
 		return nil
 	}
-	return &BuildError{Build: Build{Ref: ref}, error: err}
+	return &BuildError{Build: Build{Ref: ref, Definition: def}, error: err}
 }
 
 func (b *Build) WrapError(err error) error {

controller/errdefs/errdefs.proto

@@ -6,4 +6,5 @@ import "github.com/moby/buildkit/solver/pb/ops.proto";
 
 message Build {
   string Ref = 1;
+  pb.Definition Definition = 2;
 }