dap: add debug adapter implementation

build/build.go

@@ -313,9 +313,12 @@ func toRepoOnly(in string) (string, error) {
 	return strings.Join(out, ","), nil
 }
 
-type Handler struct {
-	Evaluate func(ctx context.Context, c gateway.Client, res *gateway.Result) error
-}
+type (
+	EvaluateFunc func(ctx context.Context, name string, c gateway.Client, res *gateway.Result) error
+	Handler      struct {
+		Evaluate EvaluateFunc
+	}
+)
 
 func Build(ctx context.Context, nodes []builder.Node, opts map[string]Options, docker *dockerutil.Client, cfg *confutil.Config, w progress.Writer) (resp map[string]*client.SolveResponse, err error) {
 	return BuildWithResultHandler(ctx, nodes, opts, docker, cfg, w, nil)
@@ -510,12 +513,25 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opts map[
 						rKey := resultKey(dp.driverIndex, k)
 						results.Set(rKey, res)
 
+						forceEval := false
 						if children := childTargets[rKey]; len(children) > 0 {
-							if err := waitForChildren(ctx, bh, c, res, results, children); err != nil {
+							// wait for the child targets to register their LLB before evaluating
+							_, err := results.Get(ctx, children...)
+							if err != nil {
 								return nil, err
 							}
-						} else if bh != nil && bh.Evaluate != nil {
-							if err := bh.Evaluate(ctx, c, res); err != nil {
+							forceEval = true
+						}
+
+						// invoke custom evaluate handler if it is present
+						if bh != nil && bh.Evaluate != nil {
+							if err := bh.Evaluate(ctx, k, c, res); err != nil {
+								return nil, err
+							}
+						} else if forceEval {
+							if err := res.EachRef(func(ref gateway.Reference) error {
+								return ref.Evaluate(ctx)
+							}); err != nil {
 								return nil, err
 							}
 						}
@@ -1199,29 +1215,6 @@ func solve(ctx context.Context, c gateway.Client, req gateway.SolveRequest) (*ga
 	return res, nil
 }
 
-func waitForChildren(ctx context.Context, bh *Handler, c gateway.Client, res *gateway.Result, results *waitmap.Map, children []string) error {
-	// wait for the child targets to register their LLB before evaluating
-	_, err := results.Get(ctx, children...)
-	if err != nil {
-		return err
-	}
-	// we need to wait until the child targets have completed before we can release
-	eg, ctx := errgroup.WithContext(ctx)
-	eg.Go(func() error {
-		if bh != nil && bh.Evaluate != nil {
-			return bh.Evaluate(ctx, c, res)
-		}
-		return res.EachRef(func(ref gateway.Reference) error {
-			return ref.Evaluate(ctx)
-		})
-	})
-	eg.Go(func() error {
-		_, err := results.Get(ctx, children...)
-		return err
-	})
-	return eg.Wait()
-}
-
 func catchFrontendError(retErr, frontendErr *error) {
 	*frontendErr = *retErr
 	if errors.Is(*retErr, ErrRestart) {

build/invoke.go

@@ -14,18 +14,18 @@ import (
 )
 
 type InvokeConfig struct {
-	Entrypoint []string
-	Cmd        []string
-	NoCmd      bool
-	Env        []string
-	User       string
-	NoUser     bool
-	Cwd        string
-	NoCwd      bool
-	Tty        bool
-	Rollback   bool
-	Initial    bool
-	SuspendOn  SuspendOn
+	Entrypoint []string  `json:"entrypoint,omitempty"`
+	Cmd        []string  `json:"cmd,omitempty"`
+	NoCmd      bool      `json:"noCmd,omitempty"`
+	Env        []string  `json:"env,omitempty"`
+	User       string    `json:"user,omitempty"`
+	NoUser     bool      `json:"noUser,omitempty"`
+	Cwd        string    `json:"cwd,omitempty"`
+	NoCwd      bool      `json:"noCwd,omitempty"`
+	Tty        bool      `json:"tty,omitempty"`
+	Rollback   bool      `json:"rollback,omitempty"`
+	Initial    bool      `json:"initial,omitempty"`
+	SuspendOn  SuspendOn `json:"suspendOn,omitempty"`
 }
 
 func (cfg *InvokeConfig) NeedsDebug(err error) bool {
@@ -43,6 +43,18 @@ func (s SuspendOn) DebugEnabled(err error) bool {
 	return err != nil || s == SuspendAlways
 }
 
+func (s *SuspendOn) UnmarshalText(text []byte) error {
+	switch string(text) {
+	case "error":
+		*s = SuspendError
+	case "always":
+		*s = SuspendAlways
+	default:
+		return errors.Errorf("unknown suspend name: %s", string(text))
+	}
+	return nil
+}
+
 type Container struct {
 	cancelOnce      sync.Once
 	containerCancel func(error)

build/result.go

@@ -16,17 +16,18 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-// NewResultHandle stores a gateway client, gateway result, and the error from
+// NewResultHandle stores a gateway client, gateway reference, and the error from
 // an evaluate call if it is present.
 //
 // This ResultHandle can be used to execute additional build steps in the same
 // context as the build occurred, which can allow easy debugging of build
 // failures and successes.
 //
 // If the returned ResultHandle is not nil, the caller must call Done() on it.
-func NewResultHandle(ctx context.Context, c gateway.Client, res *gateway.Result, err error) *ResultHandle {
+func NewResultHandle(ctx context.Context, c gateway.Client, ref gateway.Reference, meta map[string][]byte, err error) *ResultHandle {
 	rCtx := &ResultHandle{
-		res:      res,
+		ref:      ref,
+		meta:     meta,
 		gwClient: c,
 	}
 	if err != nil && !errors.As(err, &rCtx.solveErr) {
@@ -37,8 +38,9 @@ func NewResultHandle(ctx context.Context, c gateway.Client, res *gateway.Result,
 
 // ResultHandle is a build result with the client that built it.
 type ResultHandle struct {
-	res      *gateway.Result
+	ref      gateway.Reference
 	solveErr *errdefs.SolveError
+	meta     map[string][]byte
 	gwClient gateway.Client
 
 	doneOnce sync.Once
@@ -74,9 +76,9 @@ func (r *ResultHandle) NewContainer(ctx context.Context, cfg *InvokeConfig) (gat
 }
 
 func (r *ResultHandle) getContainerConfig(cfg *InvokeConfig) (containerCfg gateway.NewContainerRequest, _ error) {
-	if r.res != nil && r.solveErr == nil {
+	if r.ref != nil && r.solveErr == nil {
 		logrus.Debugf("creating container from successful build")
-		ccfg, err := containerConfigFromResult(r.res, cfg)
+		ccfg, err := containerConfigFromResult(r.ref, cfg)
 		if err != nil {
 			return containerCfg, err
 		}
@@ -94,9 +96,9 @@ func (r *ResultHandle) getContainerConfig(cfg *InvokeConfig) (containerCfg gatew
 
 func (r *ResultHandle) getProcessConfig(cfg *InvokeConfig, stdin io.ReadCloser, stdout io.WriteCloser, stderr io.WriteCloser) (_ gateway.StartRequest, err error) {
 	processCfg := newStartRequest(stdin, stdout, stderr)
-	if r.res != nil && r.solveErr == nil {
+	if r.ref != nil && r.solveErr == nil {
 		logrus.Debugf("creating container from successful build")
-		if err := populateProcessConfigFromResult(&processCfg, r.res, cfg); err != nil {
+		if err := populateProcessConfigFromResult(&processCfg, r.meta, cfg); err != nil {
 			return processCfg, err
 		}
 	} else {
@@ -108,20 +110,11 @@ func (r *ResultHandle) getProcessConfig(cfg *InvokeConfig, stdin io.ReadCloser,
 	return processCfg, nil
 }
 
-func containerConfigFromResult(res *gateway.Result, cfg *InvokeConfig) (*gateway.NewContainerRequest, error) {
+func containerConfigFromResult(ref gateway.Reference, cfg *InvokeConfig) (*gateway.NewContainerRequest, error) {
 	if cfg.Initial {
 		return nil, errors.Errorf("starting from the container from the initial state of the step is supported only on the failed steps")
 	}
 
-	ps, err := exptypes.ParsePlatforms(res.Metadata)
-	if err != nil {
-		return nil, err
-	}
-	ref, ok := res.FindRef(ps.Platforms[0].ID)
-	if !ok {
-		return nil, errors.Errorf("no reference found")
-	}
-
 	return &gateway.NewContainerRequest{
 		Mounts: []gateway.Mount{
 			{
@@ -133,8 +126,8 @@ func containerConfigFromResult(res *gateway.Result, cfg *InvokeConfig) (*gateway
 	}, nil
 }
 
-func populateProcessConfigFromResult(req *gateway.StartRequest, res *gateway.Result, cfg *InvokeConfig) error {
-	imgData := res.Metadata[exptypes.ExporterImageConfigKey]
+func populateProcessConfigFromResult(req *gateway.StartRequest, meta map[string][]byte, cfg *InvokeConfig) error {
+	imgData := meta[exptypes.ExporterImageConfigKey]
 	var img *ocispecs.Image
 	if len(imgData) > 0 {
 		img = &ocispecs.Image{}