solver: attach causing vertex in an error

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

cmd/buildctl/build.go

@@ -299,6 +299,11 @@ func buildAction(clicontext *cli.Context) error {
 	// temp test
 	if os.Getenv("BUILDCTL_DEBUG_ERROR_UNSTABLE") == "1" {
 		log.Printf("%+v", errdefs.StackFormatter(err))
+
+		var ve *errdefs.VertexError
+		if errors.As(err, &ve) {
+			log.Printf("error-vertex: %s", ve.Digest)
+		}
 	}
 
 	return err

cmd/buildkitd/main.go

@@ -342,7 +342,7 @@ func defaultConfigPath() string {
 func defaultConf() (config.Config, *toml.MetaData, error) {
 	cfg, md, err := LoadFile(defaultConfigPath())
 	if err != nil {
-		var pe os.PathError
+		var pe *os.PathError
 		if !errors.As(err, &pe) {
 			return config.Config{}, nil, err
 		}

frontend/dockerfile/parser/errors.go

@@ -25,7 +25,7 @@ func withLocation(err error, startLine, endLine int) error {
 	if err == nil {
 		return nil
 	}
-	var el ErrorLocation
+	var el *ErrorLocation
 	if errors.As(err, &el) {
 		return err
 	}

solver/errdefs/errdefs.proto

@@ -2,10 +2,6 @@ syntax = "proto3";
 
 package errdefs;
 
-import "github.com/gogo/protobuf/gogoproto/gogo.proto";
-
-option (gogoproto.stable_marshaler_all) = true;
-
 message Stack {
     repeated Frame frames = 1;
     repeated string cmdline = 2;
@@ -21,7 +17,7 @@ message Frame {
 }
 
 message Vertex {
-    string digest = 1 [(gogoproto.customtype) = "github.com/opencontainers/go-digest.Digest", (gogoproto.nullable) = false];
+    string digest = 1;
 }
 
 message Source {

solver/errdefs/grpc.go

@@ -3,6 +3,7 @@ package errdefs
 import (
 	"github.com/golang/protobuf/proto"
 	"github.com/golang/protobuf/ptypes"
+	"github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
 	spb "google.golang.org/genproto/googleapis/rpc/status"
 	"google.golang.org/grpc/codes"
@@ -29,6 +30,11 @@ func ToGRPC(err error) error {
 		details = append(details, st)
 	}
 
+	var ve *VertexError
+	if errors.As(err, &ve) {
+		details = append(details, &ve.Vertex)
+	}
+
 	if len(details) > 0 {
 		if st2, err := st.WithDetails(details...); err == nil {
 			st = st2
@@ -105,7 +111,7 @@ func FromGRPC(err error) error {
 			continue
 		}
 		switch detail.Message.(type) {
-		case *Stack:
+		case *Stack, *Vertex:
 			details = append(details, detail.Message)
 		default:
 			n.Details = append(n.Details, d)
@@ -120,6 +126,8 @@ func FromGRPC(err error) error {
 			if v != nil {
 				err = &withStack{stack: *v, error: err}
 			}
+		case *Vertex:
+			err = WrapVertex(err, digest.Digest(v.Digest))
 		}
 	}
 

solver/errdefs/stack.go

@@ -18,11 +18,6 @@ func SetVersionInfo(v, r string) {
 	revision = r
 }
 
-type VertexError struct {
-	Vertex
-	error
-}
-
 func Traces(err error) []*Stack {
 	var st []*Stack
 

solver/errdefs/vertex.go

@@ -0,0 +1,19 @@
+package errdefs
+
+import "github.com/opencontainers/go-digest"
+
+type VertexError struct {
+	Vertex
+	error
+}
+
+func (e *VertexError) Unwrap() error {
+	return e.error
+}
+
+func WrapVertex(err error, dgst digest.Digest) error {
+	if err == nil {
+		return nil
+	}
+	return &VertexError{Vertex: Vertex{Digest: dgst.String()}, error: err}
+}

solver/jobs.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/session"
+	"github.com/moby/buildkit/solver/errdefs"
 	"github.com/moby/buildkit/util/flightcontrol"
 	"github.com/moby/buildkit/util/progress"
 	"github.com/moby/buildkit/util/tracing"
@@ -53,6 +54,7 @@ type state struct {
 
 	vtx          Vertex
 	clientVertex client.Vertex
+	origDigest   digest.Digest // original LLB digest. TODO: probably better to use string ID so this isn't needed
 
 	mu    sync.Mutex
 	op    *sharedOp
@@ -318,6 +320,7 @@ func (jl *Solver) loadUnlocked(v, parent Vertex, j *Job, cache map[Vertex]Vertex
 			mainCache:    jl.opts.DefaultCache,
 			cache:        map[string]CacheManager{},
 			solver:       jl,
+			origDigest:   origVtx.Digest(),
 		}
 		jl.actives[dgst] = st
 	}
@@ -564,7 +567,10 @@ func (s *sharedOp) LoadCache(ctx context.Context, rec *CacheRecord) (Result, err
 	return res, err
 }
 
-func (s *sharedOp) CalcSlowCache(ctx context.Context, index Index, f ResultBasedCacheFunc, res Result) (digest.Digest, error) {
+func (s *sharedOp) CalcSlowCache(ctx context.Context, index Index, f ResultBasedCacheFunc, res Result) (dgst digest.Digest, err error) {
+	defer func() {
+		err = errdefs.WrapVertex(err, s.st.origDigest)
+	}()
 	key, err := s.g.Do(ctx, fmt.Sprintf("slow-compute-%d", index), func(ctx context.Context) (interface{}, error) {
 		s.slowMu.Lock()
 		// TODO: add helpers for these stored values
@@ -609,7 +615,10 @@ func (s *sharedOp) CalcSlowCache(ctx context.Context, index Index, f ResultBased
 	return key.(digest.Digest), nil
 }
 
-func (s *sharedOp) CacheMap(ctx context.Context, index int) (*cacheMapResp, error) {
+func (s *sharedOp) CacheMap(ctx context.Context, index int) (resp *cacheMapResp, err error) {
+	defer func() {
+		err = errdefs.WrapVertex(err, s.st.origDigest)
+	}()
 	op, err := s.getOp()
 	if err != nil {
 		return nil, err
@@ -665,6 +674,9 @@ func (s *sharedOp) CacheMap(ctx context.Context, index int) (*cacheMapResp, erro
 }
 
 func (s *sharedOp) Exec(ctx context.Context, inputs []Result) (outputs []Result, exporters []ExportableCacheKey, err error) {
+	defer func() {
+		err = errdefs.WrapVertex(err, s.st.origDigest)
+	}()
 	op, err := s.getOp()
 	if err != nil {
 		return nil, nil, err