dap: add ability to keep ops unique when marshaling

client/llb/marshal.go

@@ -7,6 +7,7 @@ import (
 
 	cerrdefs "github.com/containerd/errdefs"
 	"github.com/containerd/platforms"
+	"github.com/moby/buildkit/identity"
 	"github.com/moby/buildkit/solver/pb"
 	digest "github.com/opencontainers/go-digest"
 	"google.golang.org/protobuf/proto"
@@ -109,12 +110,16 @@ func MarshalConstraints(base, override *Constraints) (*pb.Op, *pb.OpMetadata) {
 		opPlatform.OSFeatures = slices.Clone(c.Platform.OSFeatures)
 	}
 
-	return &pb.Op{
+	op := &pb.Op{
 		Platform: &opPlatform,
 		Constraints: &pb.WorkerConstraints{
 			Filter: c.WorkerConstraints,
 		},
-	}, c.Metadata.ToPB()
+	}
+	if c.GenerateIdentities {
+		op.Identity = identity.NewID()
+	}
+	return op, c.Metadata.ToPB()
 }
 
 type MarshalCache struct {

client/llb/state.go

@@ -644,6 +644,14 @@ func WithCaps(caps apicaps.CapSet) ConstraintsOpt {
 	})
 }
 
+// WithIdentities will add an identity to this operation that
+// will force it to be unique.
+func WithIdentities() ConstraintsOpt {
+	return constraintsOptFunc(func(c *Constraints) {
+		c.GenerateIdentities = true
+	})
+}
+
 type constraintsWrapper struct {
 	Constraints
 }
@@ -653,12 +661,13 @@ func (cw *constraintsWrapper) applyConstraints(f func(c *Constraints)) {
 }
 
 type Constraints struct {
-	Platform          *ocispecs.Platform
-	WorkerConstraints []string
-	Metadata          OpMetadata
-	LocalUniqueID     string
-	Caps              *apicaps.CapSet
-	SourceLocations   []*SourceLocation
+	Platform           *ocispecs.Platform
+	WorkerConstraints  []string
+	Metadata           OpMetadata
+	LocalUniqueID      string
+	Caps               *apicaps.CapSet
+	SourceLocations    []*SourceLocation
+	GenerateIdentities bool
 }
 
 // OpMetadata has a more friendly interface for pb.OpMetadata.

frontend/dockerfile/builder/build.go

@@ -2,6 +2,7 @@ package builder
 
 import (
 	"context"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -30,7 +31,8 @@ import (
 const (
 	// Don't forget to update frontend documentation if you add
 	// a new build-arg: frontend/dockerfile/docs/reference.md
-	keySyntaxArg = "build-arg:BUILDKIT_SYNTAX"
+	keySyntaxArg      = "build-arg:BUILDKIT_SYNTAX"
+	keyWithIdentities = "build-arg:BUILDKIT_WITH_IDENTITIES"
 )
 
 func Build(ctx context.Context, c client.Client) (_ *client.Result, err error) {
@@ -67,6 +69,15 @@ func Build(ctx context.Context, c client.Client) (_ *client.Result, err error) {
 		}
 	}
 
+	var withIdentities bool
+	if v, ok := opts[keyWithIdentities]; ok {
+		b, err := strconv.ParseBool(v)
+		if err != nil {
+			return nil, errors.Errorf("invalid boolean value for with identities: %s", v)
+		}
+		withIdentities = b
+	}
+
 	if capsError != nil {
 		return nil, capsError
 	}
@@ -138,7 +149,12 @@ func Build(ctx context.Context, c client.Client) (_ *client.Result, err error) {
 			return nil, nil, nil, err
 		}
 
-		def, err := st.Marshal(ctx)
+		var co []llb.ConstraintsOpt
+		if withIdentities {
+			co = append(co, llb.WithIdentities())
+		}
+
+		def, err := st.Marshal(ctx, co...)
 		if err != nil {
 			return nil, nil, nil, errors.Wrapf(err, "failed to marshal LLB definition")
 		}

frontend/dockerfile/docs/reference.md

@@ -2617,6 +2617,7 @@ RUN echo "I'm building for $TARGETPLATFORM"
 | `BUILDKIT_MULTI_PLATFORM`        | Bool   | Opt into deterministic output regardless of multi-platform output or not.                                                                                                                         |
 | `BUILDKIT_SANDBOX_HOSTNAME`      | String | Set the hostname (default `buildkitsandbox`)                                                                                                                                                      |
 | `BUILDKIT_SYNTAX`                | String | Set frontend image                                                                                                                                                                                |
+| `BUILDKIT_WITH_IDENTITIES`       | Bool   | Add unique ids for each LLB operation to prevent collisions.                                                                                                                                      |
 | `SOURCE_DATE_EPOCH`              | Int    | Set the Unix timestamp for created image and layers. More info from [reproducible builds](https://reproducible-builds.org/docs/source-date-epoch/). Supported since Dockerfile 1.5, BuildKit 0.11 |
 
 #### Example: keep `.git` dir

solver/pb/json.go

@@ -14,6 +14,7 @@ type jsonOp struct {
 	}
 	Platform    *Platform          `json:"platform,omitempty"`
 	Constraints *WorkerConstraints `json:"constraints,omitempty"`
+	Identity    string             `json:"identity,omitempty"`
 }
 
 func (m *Op) MarshalJSON() ([]byte, error) {
@@ -35,6 +36,7 @@ func (m *Op) MarshalJSON() ([]byte, error) {
 	}
 	v.Platform = m.Platform
 	v.Constraints = m.Constraints
+	v.Identity = m.Identity
 	return json.Marshal(v)
 }
 
@@ -61,6 +63,7 @@ func (m *Op) UnmarshalJSON(data []byte) error {
 	}
 	m.Platform = v.Platform
 	m.Constraints = v.Constraints
+	m.Identity = v.Identity
 	return nil
 }
 

solver/pb/ops.proto

@@ -21,6 +21,7 @@ message Op {
 	}
 	Platform platform = 10;
 	WorkerConstraints constraints = 11;
+	string identity = 12;
 }
 
 // Platform is github.com/opencontainers/image-spec/specs-go/v1.Platform