Generalize format loading. (#603)

* Generalize format loading.

This refactors how formatters are initialized and configured to be more
uniform. This allows for formatter providers to be more easily slotted
in / configured without needing to make modifications for downstream
signers. The ultimate goal for this change is to allow for "type
aliasing" of formatters, where the same formatter may be referenced by
different names to allow for supporting new formats in a backwards
compatible way (i.e. letting slsa be an alias for intoto or slsa0.2,
etc.)

This follows a similar pattern to sigstore KMS providers - https://github.com/sigstore/sigstore/tree/main/pkg/signature/kms

As part of this change, the way to initialize a formatter is
standardized. To support this, the intoto logger that was previously
configured during initialization is now taken from the context.

BREAKING CHANGES:
- formats.PayloadType is now defined in config rather than formats. The
  semantics behind this value are still the same.
- CreatePayload now takes in a context.
- InTotoIte6.NewFormatter no longer takes in a logger.
- formats.AllFormatters is removed. Use formats.GetPayloader instead.

Signed-off-by: Billy Lynch <billy@chainguard.dev>

* Add formatter loaders to controllers.

Signed-off-by: Billy Lynch <billy@chainguard.dev>

pkg/artifacts/signable.go

@@ -21,7 +21,6 @@ import (
 	"github.com/google/go-containerregistry/pkg/name"
 	slsa "github.com/in-toto/in-toto-golang/in_toto/slsa_provenance/v0.2"
 	"github.com/opencontainers/go-digest"
-	"github.com/tektoncd/chains/pkg/chains/formats"
 	"github.com/tektoncd/chains/pkg/chains/objects"
 	"github.com/tektoncd/chains/pkg/config"
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline/v1beta1"
@@ -38,7 +37,7 @@ type Signable interface {
 	ExtractObjects(obj objects.TektonObject) []interface{}
 	StorageBackend(cfg config.Config) sets.String
 	Signer(cfg config.Config) string
-	PayloadFormat(cfg config.Config) formats.PayloadType
+	PayloadFormat(cfg config.Config) config.PayloadType
 	// FullKey returns the full identifier for a signable artifact.
 	// - For OCI artifact, it is the full representation in the format of `<NAME>@sha256:<DIGEST>`.
 	// - For TaskRun/PipelineRun artifact, it is `<GROUP>-<VERSION>-<KIND>-<UID>`
@@ -80,8 +79,8 @@ func (ta *TaskRunArtifact) StorageBackend(cfg config.Config) sets.String {
 	return cfg.Artifacts.TaskRuns.StorageBackend
 }
 
-func (ta *TaskRunArtifact) PayloadFormat(cfg config.Config) formats.PayloadType {
-	return formats.PayloadType(cfg.Artifacts.TaskRuns.Format)
+func (ta *TaskRunArtifact) PayloadFormat(cfg config.Config) config.PayloadType {
+	return config.PayloadType(cfg.Artifacts.TaskRuns.Format)
 }
 
 func (ta *TaskRunArtifact) Signer(cfg config.Config) string {
@@ -122,8 +121,8 @@ func (pa *PipelineRunArtifact) StorageBackend(cfg config.Config) sets.String {
 	return cfg.Artifacts.PipelineRuns.StorageBackend
 }
 
-func (pa *PipelineRunArtifact) PayloadFormat(cfg config.Config) formats.PayloadType {
-	return formats.PayloadType(cfg.Artifacts.PipelineRuns.Format)
+func (pa *PipelineRunArtifact) PayloadFormat(cfg config.Config) config.PayloadType {
+	return config.PayloadType(cfg.Artifacts.PipelineRuns.Format)
 }
 
 func (pa *PipelineRunArtifact) Signer(cfg config.Config) string {
@@ -392,8 +391,8 @@ func (oa *OCIArtifact) StorageBackend(cfg config.Config) sets.String {
 	return cfg.Artifacts.OCI.StorageBackend
 }
 
-func (oa *OCIArtifact) PayloadFormat(cfg config.Config) formats.PayloadType {
-	return formats.PayloadType(cfg.Artifacts.OCI.Format)
+func (oa *OCIArtifact) PayloadFormat(cfg config.Config) config.PayloadType {
+	return config.PayloadType(cfg.Artifacts.OCI.Format)
 }
 
 func (oa *OCIArtifact) Signer(cfg config.Config) string {

pkg/chains/formats/all/all.go

@@ -0,0 +1,21 @@
+// Copyright 2022 The Tekton Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package all
+
+import (
+	_ "github.com/tektoncd/chains/pkg/chains/formats/intotoite6"
+	_ "github.com/tektoncd/chains/pkg/chains/formats/simple"
+	_ "github.com/tektoncd/chains/pkg/chains/formats/tekton"
+)

pkg/chains/formats/format.go

@@ -13,20 +13,45 @@ limitations under the License.
 
 package formats
 
+import (
+	"context"
+	"fmt"
+
+	"github.com/tektoncd/chains/pkg/config"
+)
+
 // Payloader is an interface to generate a chains Payload from a TaskRun
 type Payloader interface {
-	CreatePayload(obj interface{}) (interface{}, error)
-	Type() PayloadType
+	CreatePayload(ctx context.Context, obj interface{}) (interface{}, error)
+	Type() config.PayloadType
 	Wrap() bool
 }
 
-type PayloadType string
-
-// If you update this, remember to update AllFormatters
 const (
-	PayloadTypeTekton        PayloadType = "tekton"
-	PayloadTypeSimpleSigning PayloadType = "simplesigning"
-	PayloadTypeInTotoIte6    PayloadType = "in-toto"
+	PayloadTypeTekton        config.PayloadType = "tekton"
+	PayloadTypeSimpleSigning config.PayloadType = "simplesigning"
+	PayloadTypeInTotoIte6    config.PayloadType = "in-toto"
+)
+
+var (
+	payloaderMap = map[config.PayloadType]PayloaderInit{}
 )
 
-var AllFormatters = []PayloadType{PayloadTypeTekton, PayloadTypeSimpleSigning, PayloadTypeInTotoIte6}
+// PayloaderInit initializes a new Payloader instance for the given config.
+type PayloaderInit func(config.Config) (Payloader, error)
+
+// RegisterPayloader registers the PayloaderInit func for the given type.
+// This is suitable to be calling during init() to register Payloader types.
+func RegisterPayloader(key config.PayloadType, init PayloaderInit) {
+	payloaderMap[key] = init
+}
+
+// GetPayloader returns a new Payloader of the given type.
+// If no Payloader is registered for the type, an error is returned.
+func GetPayloader(key config.PayloadType, cfg config.Config) (Payloader, error) {
+	fn, ok := payloaderMap[key]
+	if !ok {
+		return nil, fmt.Errorf("payloader %q not found", key)
+	}
+	return fn(cfg)
+}

pkg/chains/formats/intotoite6/intotoite6.go

@@ -17,43 +17,51 @@ limitations under the License.
 package intotoite6
 
 import (
+	"context"
 	"fmt"
 
 	"github.com/tektoncd/chains/pkg/chains/formats"
 	"github.com/tektoncd/chains/pkg/chains/formats/intotoite6/pipelinerun"
 	"github.com/tektoncd/chains/pkg/chains/formats/intotoite6/taskrun"
 	"github.com/tektoncd/chains/pkg/chains/objects"
 	"github.com/tektoncd/chains/pkg/config"
-	"go.uber.org/zap"
+	"knative.dev/pkg/logging"
 )
 
+const (
+	PayloadTypeInTotoIte6 = formats.PayloadTypeInTotoIte6
+)
+
+func init() {
+	formats.RegisterPayloader(PayloadTypeInTotoIte6, NewFormatter)
+}
+
 type InTotoIte6 struct {
 	builderID string
-	logger    *zap.SugaredLogger
 }
 
-func NewFormatter(cfg config.Config, logger *zap.SugaredLogger) (formats.Payloader, error) {
+func NewFormatter(cfg config.Config) (formats.Payloader, error) {
 	return &InTotoIte6{
 		builderID: cfg.Builder.ID,
-		logger:    logger,
 	}, nil
 }
 
 func (i *InTotoIte6) Wrap() bool {
 	return true
 }
 
-func (i *InTotoIte6) CreatePayload(obj interface{}) (interface{}, error) {
+func (i *InTotoIte6) CreatePayload(ctx context.Context, obj interface{}) (interface{}, error) {
+	logger := logging.FromContext(ctx)
 	switch v := obj.(type) {
 	case *objects.TaskRunObject:
-		return taskrun.GenerateAttestation(i.builderID, v, i.logger)
+		return taskrun.GenerateAttestation(i.builderID, v, logger)
 	case *objects.PipelineRunObject:
-		return pipelinerun.GenerateAttestation(i.builderID, v, i.logger)
+		return pipelinerun.GenerateAttestation(i.builderID, v, logger)
 	default:
 		return nil, fmt.Errorf("intoto does not support type: %s", v)
 	}
 }
 
-func (i *InTotoIte6) Type() formats.PayloadType {
+func (i *InTotoIte6) Type() config.PayloadType {
 	return formats.PayloadTypeInTotoIte6
 }

pkg/chains/formats/intotoite6/intotoite6_test.go

@@ -39,6 +39,8 @@ var e1BuildStart = time.Unix(1617011400, 0)
 var e1BuildFinished = time.Unix(1617011415, 0)
 
 func TestTaskRunCreatePayload1(t *testing.T) {
+	ctx := logtesting.TestContextWithLogger(t)
+
 	tr, err := objectloader.TaskRunFromFile("testdata/taskrun1.json")
 	if err != nil {
 		t.Fatal(err)
@@ -113,9 +115,9 @@ func TestTaskRunCreatePayload1(t *testing.T) {
 			},
 		},
 	}
-	i, _ := NewFormatter(cfg, logtesting.TestLogger(t))
+	i, _ := NewFormatter(cfg)
 
-	got, err := i.CreatePayload(objects.NewTaskRunObject(tr))
+	got, err := i.CreatePayload(ctx, objects.NewTaskRunObject(tr))
 
 	if err != nil {
 		t.Errorf("unexpected error: %s", err.Error())
@@ -126,6 +128,7 @@ func TestTaskRunCreatePayload1(t *testing.T) {
 }
 
 func TestPipelineRunCreatePayload(t *testing.T) {
+	ctx := logtesting.TestContextWithLogger(t)
 	pr, err := objectloader.PipelineRunFromFile("testdata/pipelinerun1.json")
 	if err != nil {
 		t.Fatal(err)
@@ -316,9 +319,9 @@ func TestPipelineRunCreatePayload(t *testing.T) {
 	pro.AppendTaskRun(tr1)
 	pro.AppendTaskRun(tr2)
 
-	i, _ := NewFormatter(cfg, logtesting.TestLogger(t))
+	i, _ := NewFormatter(cfg)
 
-	got, err := i.CreatePayload(pro)
+	got, err := i.CreatePayload(ctx, pro)
 	if err != nil {
 		t.Errorf("unexpected error: %s", err.Error())
 	}
@@ -327,6 +330,7 @@ func TestPipelineRunCreatePayload(t *testing.T) {
 	}
 }
 func TestPipelineRunCreatePayloadChildRefs(t *testing.T) {
+	ctx := logtesting.TestContextWithLogger(t)
 	pr, err := objectloader.PipelineRunFromFile("testdata/pipelinerun-childrefs.json")
 	if err != nil {
 		t.Fatal(err)
@@ -512,8 +516,8 @@ func TestPipelineRunCreatePayloadChildRefs(t *testing.T) {
 	pro.AppendTaskRun(tr1)
 	pro.AppendTaskRun(tr2)
 
-	i, _ := NewFormatter(cfg, logtesting.TestLogger(t))
-	got, err := i.CreatePayload(pro)
+	i, _ := NewFormatter(cfg)
+	got, err := i.CreatePayload(ctx, pro)
 	if err != nil {
 		t.Errorf("unexpected error: %s", err.Error())
 	}
@@ -523,6 +527,7 @@ func TestPipelineRunCreatePayloadChildRefs(t *testing.T) {
 }
 
 func TestTaskRunCreatePayload2(t *testing.T) {
+	ctx := logtesting.TestContextWithLogger(t)
 	tr, err := objectloader.TaskRunFromFile("testdata/taskrun2.json")
 	if err != nil {
 		t.Fatal(err)
@@ -578,8 +583,8 @@ func TestTaskRunCreatePayload2(t *testing.T) {
 			},
 		},
 	}
-	i, _ := NewFormatter(cfg, logtesting.TestLogger(t))
-	got, err := i.CreatePayload(objects.NewTaskRunObject(tr))
+	i, _ := NewFormatter(cfg)
+	got, err := i.CreatePayload(ctx, objects.NewTaskRunObject(tr))
 
 	if err != nil {
 		t.Errorf("unexpected error: %s", err.Error())
@@ -590,6 +595,8 @@ func TestTaskRunCreatePayload2(t *testing.T) {
 }
 
 func TestMultipleSubjects(t *testing.T) {
+	ctx := logtesting.TestContextWithLogger(t)
+
 	tr, err := objectloader.TaskRunFromFile("testdata/taskrun-multiple-subjects.json")
 	if err != nil {
 		t.Fatal(err)
@@ -641,8 +648,8 @@ func TestMultipleSubjects(t *testing.T) {
 		},
 	}
 
-	i, _ := NewFormatter(cfg, logtesting.TestLogger(t))
-	got, err := i.CreatePayload(objects.NewTaskRunObject(tr))
+	i, _ := NewFormatter(cfg)
+	got, err := i.CreatePayload(ctx, objects.NewTaskRunObject(tr))
 	if err != nil {
 		t.Errorf("unexpected error: %s", err.Error())
 	}
@@ -658,7 +665,7 @@ func TestNewFormatter(t *testing.T) {
 				ID: "testid",
 			},
 		}
-		f, err := NewFormatter(cfg, logtesting.TestLogger(t))
+		f, err := NewFormatter(cfg)
 		if f == nil {
 			t.Error("Failed to create formatter")
 		}
@@ -669,15 +676,17 @@ func TestNewFormatter(t *testing.T) {
 }
 
 func TestCreatePayloadError(t *testing.T) {
+	ctx := logtesting.TestContextWithLogger(t)
+
 	cfg := config.Config{
 		Builder: config.BuilderConfig{
 			ID: "testid",
 		},
 	}
-	f, _ := NewFormatter(cfg, logtesting.TestLogger(t))
+	f, _ := NewFormatter(cfg)
 
 	t.Run("Invalid type", func(t *testing.T) {
-		p, err := f.CreatePayload("not a task ref")
+		p, err := f.CreatePayload(ctx, "not a task ref")
 
 		if p != nil {
 			t.Errorf("Unexpected payload")

pkg/chains/formats/simple/simple.go

@@ -14,23 +14,32 @@ limitations under the License.
 package simple
 
 import (
+	"context"
 	"fmt"
 
 	"github.com/sigstore/sigstore/pkg/signature/payload"
 	"github.com/tektoncd/chains/pkg/chains/formats"
+	"github.com/tektoncd/chains/pkg/config"
 
 	"github.com/google/go-containerregistry/pkg/name"
 )
 
+const (
+	PayloadTypeSimpleSigning = formats.PayloadTypeSimpleSigning
+)
+
+func init() {
+	formats.RegisterPayloader(PayloadTypeSimpleSigning, NewFormatter)
+}
+
 // SimpleSigning is a formatter that uses the RedHat simple signing format
 // https://www.redhat.com/en/blog/container-image-signing
-type SimpleSigning struct {
-}
+type SimpleSigning struct{}
 
 type SimpleContainerImage payload.SimpleContainerImage
 
 // CreatePayload implements the Payloader interface.
-func (i *SimpleSigning) CreatePayload(obj interface{}) (interface{}, error) {
+func (i *SimpleSigning) CreatePayload(ctx context.Context, obj interface{}) (interface{}, error) {
 	switch v := obj.(type) {
 	case name.Digest:
 		format := NewSimpleStruct(v)
@@ -44,7 +53,7 @@ func (i *SimpleSigning) Wrap() bool {
 	return false
 }
 
-func NewFormatter() (formats.Payloader, error) {
+func NewFormatter(config.Config) (formats.Payloader, error) {
 	return &SimpleSigning{}, nil
 }
 
@@ -57,6 +66,6 @@ func (i SimpleContainerImage) ImageName() string {
 	return fmt.Sprintf("%s@%s", i.Critical.Identity.DockerReference, i.Critical.Image.DockerManifestDigest)
 }
 
-func (i *SimpleSigning) Type() formats.PayloadType {
+func (i *SimpleSigning) Type() config.PayloadType {
 	return formats.PayloadTypeSimpleSigning
 }

pkg/chains/formats/simple/simple_test.go

@@ -14,6 +14,7 @@ limitations under the License.
 package simple
 
 import (
+	"context"
 	"reflect"
 	"testing"
 
@@ -61,7 +62,7 @@ func TestSimpleSigning_CreatePayload(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			i := &SimpleSigning{}
-			got, err := i.CreatePayload(tt.obj)
+			got, err := i.CreatePayload(context.Background(), tt.obj)
 			if (err != nil) != tt.wantErr {
 				t.Errorf("SimpleSigning.CreatePayload() error = %v, wantErr %v", err, tt.wantErr)
 				return
@@ -81,7 +82,7 @@ func TestImageName(t *testing.T) {
 	obj := makeDigest(t, img)
 
 	i := &SimpleSigning{}
-	format, err := i.CreatePayload(obj)
+	format, err := i.CreatePayload(context.Background(), obj)
 	if err != nil {
 		t.Fatal(err)
 	}