Merge branch 'main' into fix-oci-layout-referrers

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
       id-token: write
     strategy:
       matrix:
-        go-version: [1.21.x]
+        go-version: [1.22.x]
         # temp disable windows tests see https://github.com/docker/image-signer-verifier/pull/154
         # os: [ubuntu-latest, macos-latest, windows-latest]
         os: [ubuntu-latest, macos-latest]

internal/test/mocks.go

@@ -16,15 +16,15 @@ type MockResolver struct {
 	Envs []*attestation.Envelope
 }
 
-func (r MockResolver) Attestations(ctx context.Context, mediaType string) ([]*attestation.Envelope, error) {
+func (r MockResolver) Attestations(_ context.Context, _ string) ([]*attestation.Envelope, error) {
 	return r.Envs, nil
 }
 
-func (r MockResolver) ImageName(ctx context.Context) (string, error) {
+func (r MockResolver) ImageName(_ context.Context) (string, error) {
 	return "library/alpine:latest", nil
 }
 
-func (r MockResolver) ImageDescriptor(ctx context.Context) (*v1.Descriptor, error) {
+func (r MockResolver) ImageDescriptor(_ context.Context) (*v1.Descriptor, error) {
 	digest, err := v1.NewHash("sha256:da8b190665956ea07890a0273e2a9c96bfe291662f08e2860e868eef69c34620")
 	if err != nil {
 		return nil, err
@@ -36,7 +36,7 @@ func (r MockResolver) ImageDescriptor(ctx context.Context) (*v1.Descriptor, erro
 	}, nil
 }
 
-func (r MockResolver) ImagePlatform(ctx context.Context) (*v1.Platform, error) {
+func (r MockResolver) ImagePlatform(_ context.Context) (*v1.Platform, error) {
 	return oci.ParsePlatform("linux/amd64")
 }
 
@@ -46,15 +46,15 @@ type MockRegistryResolver struct {
 	*MockResolver
 }
 
-func (r *MockRegistryResolver) ImageDescriptor(ctx context.Context) (*v1.Descriptor, error) {
+func (r *MockRegistryResolver) ImageDescriptor(_ context.Context) (*v1.Descriptor, error) {
 	return r.Subject, nil
 }
 
-func (r *MockRegistryResolver) ImageName(ctx context.Context) (string, error) {
+func (r *MockRegistryResolver) ImageName(_ context.Context) (string, error) {
 	return r.ImageNameStr, nil
 }
 
-func GetMockSigner(ctx context.Context) (dsse.SignerVerifier, error) {
+func GetMockSigner(_ context.Context) (dsse.SignerVerifier, error) {
 	priv, err := os.ReadFile(filepath.Join("..", "..", "test", "testdata", "test-signing-key.pem"))
 	if err != nil {
 		return nil, err

internal/test/test.go

@@ -21,12 +21,12 @@ import (
 )
 
 const (
-	USE_MOCK_TL     = true
-	USE_MOCK_KMS    = true
-	USE_MOCK_POLICY = true
+	UseMockTL     = true
+	UseMockKMS    = true
+	UseMockPolicy = true
 
-	AwsRegion    = "us-east-1"
-	AwsKmsKeyArn = "arn:aws:kms:us-east-1:175142243308:alias/doi-signing" // sandbox
+	AWSRegion    = "us-east-1"
+	AWSKMSKeyARN = "arn:aws:kms:us-east-1:175142243308:alias/doi-signing" // sandbox
 )
 
 func CreateTempDir(t *testing.T, dir, pattern string) string {
@@ -47,7 +47,7 @@ func CreateTempDir(t *testing.T, dir, pattern string) string {
 
 func Setup(t *testing.T) (context.Context, dsse.SignerVerifier) {
 	var tl tlog.TL
-	if USE_MOCK_TL {
+	if UseMockTL {
 		tl = tlog.GetMockTL()
 	} else {
 		tl = &tlog.RekorTL{}
@@ -55,8 +55,8 @@ func Setup(t *testing.T) (context.Context, dsse.SignerVerifier) {
 
 	ctx := tlog.WithTL(context.Background(), tl)
 
-	var policyEvaluator policy.PolicyEvaluator
-	if USE_MOCK_POLICY {
+	var policyEvaluator policy.Evaluator
+	if UseMockPolicy {
 		policyEvaluator = policy.GetMockPolicy()
 	} else {
 		policyEvaluator = policy.NewRegoEvaluator(true)
@@ -66,13 +66,13 @@ func Setup(t *testing.T) (context.Context, dsse.SignerVerifier) {
 
 	var signer dsse.SignerVerifier
 	var err error
-	if USE_MOCK_KMS {
+	if UseMockKMS {
 		signer, err = GetMockSigner(ctx)
 		if err != nil {
 			t.Fatal(err)
 		}
 	} else {
-		signer, err = signerverifier.GetAWSSigner(ctx, AwsKmsKeyArn, AwsRegion)
+		signer, err = signerverifier.GetAWSSigner(ctx, AWSKMSKeyARN, AWSRegion)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -95,7 +95,8 @@ func ExtractStatementsFromIndex(idx v1.ImageIndex, mediaType string) ([]*Annotat
 
 	var statements []*AnnotatedStatement
 
-	for _, mf := range mfs2.Manifests {
+	for i := range mfs2.Manifests {
+		mf := &mfs2.Manifests[i]
 		if mf.Annotations[attestation.DockerReferenceType] != "attestation-manifest" {
 			continue
 		}
@@ -124,7 +125,7 @@ func ExtractStatementsFromIndex(idx v1.ImageIndex, mediaType string) ([]*Annotat
 				return nil, fmt.Errorf("failed to get layer contents: %w", err)
 			}
 			defer r.Close()
-			intotoStatement := new(intoto.Statement)
+			inTotoStatement := new(intoto.Statement)
 			var desc *v1.Descriptor
 			if strings.HasSuffix(string(mt), "+dsse") {
 				env := new(attestation.Envelope)
@@ -136,7 +137,7 @@ func ExtractStatementsFromIndex(idx v1.ImageIndex, mediaType string) ([]*Annotat
 				if err != nil {
 					return nil, fmt.Errorf("failed to decode payload: %w", err)
 				}
-				err = json.Unmarshal([]byte(payload), intotoStatement)
+				err = json.Unmarshal([]byte(payload), inTotoStatement)
 				if err != nil {
 					return nil, fmt.Errorf("failed to decode %s statement: %w", mediaType, err)
 				}
@@ -158,7 +159,7 @@ func ExtractStatementsFromIndex(idx v1.ImageIndex, mediaType string) ([]*Annotat
 			}
 			statements = append(statements, &AnnotatedStatement{
 				OCIDescriptor:   desc,
-				InTotoStatement: intotoStatement,
+				InTotoStatement: inTotoStatement,
 				Annotations:     annotations,
 			})
 		}

pkg/attest/example_sign_test.go

@@ -66,7 +66,7 @@ func ExampleSignStatements_remote() {
 		Add: signedIndex,
 		Descriptor: v1.Descriptor{
 			Annotations: map[string]string{
-				oci.OciReferenceTarget: attIdx.Name,
+				oci.OCIReferenceTarget: attIdx.Name,
 			},
 		},
 	})

pkg/attest/example_verify_test.go

@@ -13,7 +13,7 @@ import (
 	"github.com/docker/attest/pkg/tuf"
 )
 
-func createTufClient(outputPath string) (*tuf.TufClient, error) {
+func createTufClient(outputPath string) (*tuf.Client, error) {
 	// using oci tuf metadata and targets
 	metadataURI := "registry-1.docker.io/docker/tuf-metadata:latest"
 	targetsURI := "registry-1.docker.io/docker/tuf-targets"
@@ -21,7 +21,7 @@ func createTufClient(outputPath string) (*tuf.TufClient, error) {
 	// metadataURI := "https://docker.github.io/tuf-staging/metadata"
 	// targetsURI := "https://docker.github.io/tuf-staging/targets"
 
-	return tuf.NewTufClient(embed.RootStaging.Data, outputPath, metadataURI, targetsURI, tuf.NewMockVersionChecker())
+	return tuf.NewClient(embed.RootStaging.Data, outputPath, metadataURI, targetsURI, tuf.NewMockVersionChecker())
 }
 
 func ExampleVerify_remote() {
@@ -41,11 +41,11 @@ func ExampleVerify_remote() {
 	platform := "linux/amd64"
 
 	// configure policy options
-	opts := &policy.PolicyOptions{
-		TufClient:       tufClient,
+	opts := &policy.Options{
+		TUFClient:       tufClient,
 		LocalTargetsDir: filepath.Join(home, ".docker", "policy"), // location to store policy files downloaded from TUF
 		LocalPolicyDir:  "",                                       // overrides TUF policy for local policy files if set
-		PolicyId:        "",                                       // set to ignore policy mapping and select a policy by id
+		PolicyID:        "",                                       // set to ignore policy mapping and select a policy by id
 	}
 
 	src, err := oci.ParseImageSpec(image, oci.WithPlatform(platform))

pkg/attest/sign.go

@@ -9,8 +9,8 @@ import (
 	"github.com/secure-systems-lab/go-securesystemslib/dsse"
 )
 
-// this is only relevant if there are (unsigned) in-toto statements
-func SignStatements(ctx context.Context, idx v1.ImageIndex, signer dsse.SignerVerifier, opts *attestation.SigningOptions) ([]*attestation.AttestationManifest, error) {
+// this is only relevant if there are (unsigned) in-toto statements.
+func SignStatements(ctx context.Context, idx v1.ImageIndex, signer dsse.SignerVerifier, opts *attestation.SigningOptions) ([]*attestation.Manifest, error) {
 	// extract attestation manifests from index
 	attestationManifests, err := attestation.GetAttestationManifestsFromIndex(idx)
 	if err != nil {

pkg/attest/sign_test.go

@@ -52,7 +52,7 @@ func TestSignVerifyOCILayout(t *testing.T) {
 		{"no provenance (replace)", NoProvenanceImage, 0, 2, true},
 		{"no provenance (no replace)", NoProvenanceImage, 2, 2, false},
 	}
-	policyOpts := &policy.PolicyOptions{
+	policyOpts := &policy.Options{
 		LocalPolicyDir: PassPolicyDir,
 	}
 	for _, tc := range testCases {
@@ -72,7 +72,7 @@ func TestSignVerifyOCILayout(t *testing.T) {
 				Add: signedIndex,
 				Descriptor: v1.Descriptor{
 					Annotations: map[string]string{
-						oci.OciReferenceTarget: attIdx.Name,
+						oci.OCIReferenceTarget: attIdx.Name,
 					},
 				},
 			})
@@ -120,7 +120,7 @@ func TestAddSignedLayerAnnotations(t *testing.T) {
 			testLayer := static.NewLayer(data, types.MediaType(intoto.PayloadType))
 			mediaType := types.OCIManifestSchema1
 			opts := &attestation.SigningOptions{}
-			originalLayer := &attestation.AttestationLayer{
+			originalLayer := &attestation.Layer{
 				Layer: testLayer,
 				Statement: &intoto.Statement{
 					StatementHeader: intoto.StatementHeader{
@@ -130,11 +130,11 @@ func TestAddSignedLayerAnnotations(t *testing.T) {
 				Annotations: map[string]string{"test": "test"},
 			}
 
-			manifest := &attestation.AttestationManifest{
+			manifest := &attestation.Manifest{
 				OriginalDescriptor: &v1.Descriptor{
 					MediaType: mediaType,
 				},
-				OriginalLayers: []*attestation.AttestationLayer{
+				OriginalLayers: []*attestation.Layer{
 					originalLayer,
 				},
 				SubjectDescriptor: &v1.Descriptor{},

pkg/attest/types.go

@@ -30,7 +30,7 @@ func (o Outcome) StringForVSA() (string, error) {
 type VerificationResult struct {
 	Outcome           Outcome
 	Policy            *policy.Policy
-	Input             *policy.PolicyInput
+	Input             *policy.Input
 	VSA               *intoto.Statement
 	Violations        []policy.Violation
 	SubjectDescriptor *v1.Descriptor

pkg/attest/verify.go

@@ -15,7 +15,7 @@ import (
 	intoto "github.com/in-toto/in-toto-golang/in_toto"
 )
 
-func Verify(ctx context.Context, src *oci.ImageSpec, opts *policy.PolicyOptions) (result *VerificationResult, err error) {
+func Verify(ctx context.Context, src *oci.ImageSpec, opts *policy.Options) (result *VerificationResult, err error) {
 	// so that we can resolve mapping from the image name earlier
 	detailsResolver, err := policy.CreateImageDetailsResolver(src)
 	if err != nil {
@@ -61,16 +61,16 @@ func Verify(ctx context.Context, src *oci.ImageSpec, opts *policy.PolicyOptions)
 	return result, nil
 }
 
-func toVerificationResult(p *policy.Policy, input *policy.PolicyInput, result *policy.Result) (*VerificationResult, error) {
+func toVerificationResult(p *policy.Policy, input *policy.Input, result *policy.Result) (*VerificationResult, error) {
 	dgst, err := oci.SplitDigest(input.Digest)
 	if err != nil {
 		return nil, fmt.Errorf("failed to split digest: %w", err)
 	}
 	subject := intoto.Subject{
-		Name:   input.Purl,
+		Name:   input.PURL,
 		Digest: dgst,
 	}
-	resourceUri, err := attestation.ToVSAResourceURI(subject)
+	resourceURI, err := attestation.ToVSAResourceURI(subject)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create resource uri: %w", err)
 	}
@@ -103,7 +103,7 @@ func toVerificationResult(p *policy.Policy, input *policy.PolicyInput, result *p
 					ID: result.Summary.Verifier,
 				},
 				TimeVerified:       time.Now().UTC().Format(time.RFC3339),
-				ResourceUri:        resourceUri,
+				ResourceURI:        resourceURI,
 				Policy:             attestation.VSAPolicy{URI: result.Summary.PolicyURI},
 				VerificationResult: outcomeStr,
 				VerifiedLevels:     result.Summary.SLSALevels,
@@ -143,9 +143,9 @@ func VerifyAttestations(ctx context.Context, resolver oci.AttestationResolver, p
 	if err != nil {
 		return nil, fmt.Errorf("failed to convert ref to purl: %w", err)
 	}
-	input := &policy.PolicyInput{
+	input := &policy.Input{
 		Digest:      digest,
-		Purl:        purl,
+		PURL:        purl,
 		IsCanonical: canonical,
 	}
 
@@ -165,12 +165,12 @@ func VerifyAttestations(ctx context.Context, resolver oci.AttestationResolver, p
 	return verificationResult, nil
 }
 
-func NewAttestationManifest(subject *v1.Descriptor) (*attestation.AttestationManifest, error) {
-	return &attestation.AttestationManifest{
+func NewAttestationManifest(subject *v1.Descriptor) (*attestation.Manifest, error) {
+	return &attestation.Manifest{
 		OriginalDescriptor: &v1.Descriptor{
 			MediaType: "application/vnd.oci.image.manifest.v1+json",
 		},
-		OriginalLayers:    []*attestation.AttestationLayer{},
+		OriginalLayers:    []*attestation.Layer{},
 		SubjectDescriptor: subject,
 	}, nil
 }

pkg/attest/verify_test.go

@@ -50,7 +50,7 @@ func TestVerifyAttestations(t *testing.T) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			mockPE := policy.MockPolicyEvaluator{
-				EvaluateFunc: func(ctx context.Context, resolver oci.AttestationResolver, pctx *policy.Policy, input *policy.PolicyInput) (*policy.Result, error) {
+				EvaluateFunc: func(_ context.Context, _ oci.AttestationResolver, _ *policy.Policy, _ *policy.Input) (*policy.Result, error) {
 					return policy.AllowedResult(), tc.policyEvaluationError
 				},
 			}
@@ -89,7 +89,7 @@ func TestVSA(t *testing.T) {
 		Add: signedIndex,
 		Descriptor: v1.Descriptor{
 			Annotations: map[string]string{
-				oci.OciReferenceTarget: attIdx.Name,
+				oci.OCIReferenceTarget: attIdx.Name,
 			},
 		},
 	})
@@ -97,7 +97,7 @@ func TestVSA(t *testing.T) {
 	assert.NoError(t, err)
 
 	// mocked vsa query should pass
-	policyOpts := &policy.PolicyOptions{
+	policyOpts := &policy.Options{
 		LocalPolicyDir: PassPolicyDir,
 	}
 	src, err := oci.ParseImageSpec("oci://"+outputLayout, oci.WithPlatform(LinuxAMD64))
@@ -117,7 +117,8 @@ func TestVSA(t *testing.T) {
 	assert.Len(t, results.VSA.Subject, 1)
 
 	require.IsType(t, attestation.VSAPredicate{}, results.VSA.Predicate)
-	attestationPredicate := results.VSA.Predicate.(attestation.VSAPredicate)
+	attestationPredicate, ok := results.VSA.Predicate.(attestation.VSAPredicate)
+	require.True(t, ok)
 
 	assert.Equal(t, "PASSED", attestationPredicate.VerificationResult)
 	assert.Equal(t, "docker-official-images", attestationPredicate.Verifier.ID)
@@ -146,7 +147,7 @@ func TestVerificationFailure(t *testing.T) {
 		Add: signedIndex,
 		Descriptor: v1.Descriptor{
 			Annotations: map[string]string{
-				oci.OciReferenceTarget: attIdx.Name,
+				oci.OCIReferenceTarget: attIdx.Name,
 			},
 		},
 	})
@@ -154,7 +155,7 @@ func TestVerificationFailure(t *testing.T) {
 	assert.NoError(t, err)
 
 	// mocked vsa query should fail
-	policyOpts := &policy.PolicyOptions{
+	policyOpts := &policy.Options{
 		LocalPolicyDir: FailPolicyDir,
 	}
 	src, err := oci.ParseImageSpec("oci://"+outputLayout, oci.WithPlatform(LinuxAMD64))
@@ -174,7 +175,8 @@ func TestVerificationFailure(t *testing.T) {
 	assert.Len(t, results.VSA.Subject, 1)
 
 	require.IsType(t, attestation.VSAPredicate{}, results.VSA.Predicate)
-	attestationPredicate := results.VSA.Predicate.(attestation.VSAPredicate)
+	attestationPredicate, ok := results.VSA.Predicate.(attestation.VSAPredicate)
+	require.True(t, ok)
 
 	assert.Equal(t, "FAILED", attestationPredicate.VerificationResult)
 	assert.Equal(t, "docker-official-images", attestationPredicate.Verifier.ID)
@@ -227,14 +229,14 @@ func TestSignVerify(t *testing.T) {
 				Add: signedIndex,
 				Descriptor: v1.Descriptor{
 					Annotations: map[string]string{
-						oci.OciReferenceTarget: imageName,
+						oci.OCIReferenceTarget: imageName,
 					},
 				},
 			})
 			_, err = layout.Write(outputLayout, idx)
 			assert.NoError(t, err)
 
-			policyOpts := &policy.PolicyOptions{
+			policyOpts := &policy.Options{
 				LocalPolicyDir: tc.policyDir,
 			}
 			src, err := oci.ParseImageSpec("oci://"+outputLayout, oci.WithPlatform(LinuxAMD64))
@@ -250,7 +252,7 @@ func TestSignVerify(t *testing.T) {
 			require.NoError(t, err)
 			expectedPURL, _, err := oci.RefToPURL(attIdx.Name, platform)
 			require.NoError(t, err)
-			assert.Equal(t, expectedPURL, results.Input.Purl)
+			assert.Equal(t, expectedPURL, results.Input.PURL)
 		})
 	}
 }

pkg/attestation/attestation.go

@@ -17,19 +17,21 @@ import (
 	"github.com/secure-systems-lab/go-securesystemslib/dsse"
 )
 
-// GetAttestationManifestsFromIndex extracts all attestation manifests from an index
-func GetAttestationManifestsFromIndex(index v1.ImageIndex) ([]*AttestationManifest, error) {
+// GetAttestationManifestsFromIndex extracts all attestation manifests from an index.
+func GetAttestationManifestsFromIndex(index v1.ImageIndex) ([]*Manifest, error) {
 	idx, err := index.IndexManifest()
 	if err != nil {
 		return nil, fmt.Errorf("failed to extract IndexManifest from ImageIndex: %w", err)
 	}
 	subjects := make(map[string]*v1.Descriptor)
-	for _, subject := range idx.Manifests {
-		subjects[subject.Digest.String()] = &subject
+	for i := range idx.Manifests {
+		subject := &idx.Manifests[i]
+		subjects[subject.Digest.String()] = subject
 	}
 
-	var attestationManifests []*AttestationManifest
-	for _, desc := range idx.Manifests {
+	var attestationManifests []*Manifest
+	for i := range idx.Manifests {
+		desc := idx.Manifests[i]
 		if desc.Annotations[DockerReferenceType] == AttestationManifestType {
 			subject := subjects[desc.Annotations[DockerReferenceDigest]]
 			if subject == nil {
@@ -44,7 +46,7 @@ func GetAttestationManifestsFromIndex(index v1.ImageIndex) ([]*AttestationManife
 				return nil, fmt.Errorf("failed to get attestations from image: %w", err)
 			}
 			attestationManifests = append(attestationManifests,
-				&AttestationManifest{
+				&Manifest{
 					OriginalDescriptor: &desc,
 					SubjectDescriptor:  subject,
 					OriginalLayers:     attestationLayers,
@@ -54,13 +56,13 @@ func GetAttestationManifestsFromIndex(index v1.ImageIndex) ([]*AttestationManife
 	return attestationManifests, nil
 }
 
-// GetAttestationsFromImage extracts all attestation layers from an image
-func GetAttestationsFromImage(image v1.Image) ([]*AttestationLayer, error) {
+// GetAttestationsFromImage extracts all attestation layers from an image.
+func GetAttestationsFromImage(image v1.Image) ([]*Layer, error) {
 	layers, err := image.Layers()
 	if err != nil {
 		return nil, fmt.Errorf("failed to extract layers from image: %w", err)
 	}
-	var attestationLayers []*AttestationLayer
+	var attestationLayers []*Layer
 	for _, layer := range layers {
 		// parse layer blob as json
 		r, err := layer.Uncompressed()
@@ -86,12 +88,12 @@ func GetAttestationsFromImage(image v1.Image) ([]*AttestationLayer, error) {
 				return nil, fmt.Errorf("failed to decode statement layer contents: %w", err)
 			}
 		}
-		attestationLayers = append(attestationLayers, &AttestationLayer{Layer: layer, Statement: stmt, Annotations: ann})
+		attestationLayers = append(attestationLayers, &Layer{Layer: layer, Statement: stmt, Annotations: ann})
 	}
 	return attestationLayers, nil
 }
 
-func (manifest *AttestationManifest) AddAttestation(ctx context.Context, signer dsse.SignerVerifier, statement *intoto.Statement, opts *SigningOptions) error {
+func (manifest *Manifest) AddAttestation(ctx context.Context, signer dsse.SignerVerifier, statement *intoto.Statement, opts *SigningOptions) error {
 	layer, err := createSignedImageLayer(ctx, statement, signer, opts)
 	if err != nil {
 		return fmt.Errorf("failed to create signed layer: %w", err)
@@ -100,7 +102,7 @@ func (manifest *AttestationManifest) AddAttestation(ctx context.Context, signer
 	return nil
 }
 
-func createSignedImageLayer(ctx context.Context, statement *intoto.Statement, signer dsse.SignerVerifier, opts *SigningOptions) (*AttestationLayer, error) {
+func createSignedImageLayer(ctx context.Context, statement *intoto.Statement, signer dsse.SignerVerifier, opts *SigningOptions) (*Layer, error) {
 	// sign the statement
 	env, err := SignInTotoStatement(ctx, statement, signer, opts)
 	if err != nil {
@@ -115,7 +117,7 @@ func createSignedImageLayer(ctx context.Context, statement *intoto.Statement, si
 	if err != nil {
 		return nil, fmt.Errorf("failed to marshal envelope: %w", err)
 	}
-	return &AttestationLayer{
+	return &Layer{
 		Statement: statement,
 		Annotations: map[string]string{
 			InTotoPredicateType:           statement.PredicateType,
@@ -139,8 +141,8 @@ func SignInTotoStatement(ctx context.Context, statement *intoto.Statement, signe
 
 func UpdateIndexImage(
 	idx v1.ImageIndex,
-	manifest *AttestationManifest,
-	options ...func(*AttestationManifestImageOptions) error,
+	manifest *Manifest,
+	options ...func(*ManifestImageOptions) error,
 ) (v1.ImageIndex, error) {
 	image, err := manifest.BuildAttestationImage(options...)
 	if err != nil {
@@ -164,7 +166,7 @@ func UpdateIndexImage(
 	return idx, nil
 }
 
-func UpdateIndexImages(idx v1.ImageIndex, manifest []*AttestationManifest, options ...func(*AttestationManifestImageOptions) error) (v1.ImageIndex, error) {
+func UpdateIndexImages(idx v1.ImageIndex, manifest []*Manifest, options ...func(*ManifestImageOptions) error) (v1.ImageIndex, error) {
 	var err error
 	for _, m := range manifest {
 		idx, err = UpdateIndexImage(idx, m, options...)
@@ -175,8 +177,8 @@ func UpdateIndexImages(idx v1.ImageIndex, manifest []*AttestationManifest, optio
 	return idx, nil
 }
 
-func newOptions(options ...func(*AttestationManifestImageOptions) error) (*AttestationManifestImageOptions, error) {
-	opts := &AttestationManifestImageOptions{}
+func newOptions(options ...func(*ManifestImageOptions) error) (*ManifestImageOptions, error) {
+	opts := &ManifestImageOptions{}
 	for _, opt := range options {
 		err := opt(opts)
 		if err != nil {
@@ -186,22 +188,22 @@ func newOptions(options ...func(*AttestationManifestImageOptions) error) (*Attes
 	return opts, nil
 }
 
-func WithoutSubject(skipSubject bool) func(*AttestationManifestImageOptions) error {
-	return func(r *AttestationManifestImageOptions) error {
+func WithoutSubject(skipSubject bool) func(*ManifestImageOptions) error {
+	return func(r *ManifestImageOptions) error {
 		r.skipSubject = skipSubject
 		return nil
 	}
 }
 
-func WithReplacedLayers(replaceLayers bool) func(*AttestationManifestImageOptions) error {
-	return func(r *AttestationManifestImageOptions) error {
+func WithReplacedLayers(replaceLayers bool) func(*ManifestImageOptions) error {
+	return func(r *ManifestImageOptions) error {
 		r.replaceLayers = replaceLayers
 		return nil
 	}
 }
 
-// build an image with signed attestations, optionally replacing existing layers with signed layers
-func (manifest *AttestationManifest) BuildAttestationImage(options ...func(*AttestationManifestImageOptions) error) (v1.Image, error) {
+// build an image with signed attestations, optionally replacing existing layers with signed layers.
+func (manifest *Manifest) BuildAttestationImage(options ...func(*ManifestImageOptions) error) (v1.Image, error) {
 	opts, err := newOptions(options...)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create options: %w", err)
@@ -224,7 +226,7 @@ func (manifest *AttestationManifest) BuildAttestationImage(options ...func(*Atte
 			resultLayers = append(resultLayers, existingLayer)
 		}
 	}
-	// so taht we attach all attestations to a single attestations image - as per current buildkit
+	// so that we attach all attestations to a single attestations image - as per current buildkit
 	opts.laxReferrers = true
 	newImg, err := buildImage(resultLayers, manifest.OriginalDescriptor, manifest.SubjectDescriptor, opts)
 	if err != nil {
@@ -233,12 +235,12 @@ func (manifest *AttestationManifest) BuildAttestationImage(options ...func(*Atte
 	return newImg, nil
 }
 
-// build an image per attestation (layer) suitable for use as Referrers
-func (manifest *AttestationManifest) BuildReferringArtifacts() ([]v1.Image, error) {
+// build an image per attestation (layer) suitable for use as Referrers.
+func (manifest *Manifest) BuildReferringArtifacts() ([]v1.Image, error) {
 	var images []v1.Image
 	for _, layer := range manifest.SignedLayers {
-		opts := &AttestationManifestImageOptions{}
-		newImg, err := buildImage([]*AttestationLayer{layer}, manifest.OriginalDescriptor, manifest.SubjectDescriptor, opts)
+		opts := &ManifestImageOptions{}
+		newImg, err := buildImage([]*Layer{layer}, manifest.OriginalDescriptor, manifest.SubjectDescriptor, opts)
 		if err != nil {
 			return nil, fmt.Errorf("failed to build image: %w", err)
 		}
@@ -247,14 +249,14 @@ func (manifest *AttestationManifest) BuildReferringArtifacts() ([]v1.Image, erro
 	return images, nil
 }
 
-// build and image containing only layers
-func buildImage(layers []*AttestationLayer, manifest *v1.Descriptor, subject *v1.Descriptor, opts *AttestationManifestImageOptions) (v1.Image, error) {
+// build and image containing only layers.
+func buildImage(layers []*Layer, manifest *v1.Descriptor, subject *v1.Descriptor, opts *ManifestImageOptions) (v1.Image, error) {
 	newImg := empty.Image
 	var err error
 	if len(layers) == 0 {
 		return nil, fmt.Errorf("no layers supplied to build image")
 	}
-	// NB: if we add the subject before the layers, it does not end up being computed/serialised in the output for some reason
+	// NB: if we add the subject before the layers, it does not end up being computed/serialized in the output for some reason
 	// TODO - recreate this bug and push upstream
 	for _, layer := range layers {
 		add := mutate.Addendum{
@@ -285,7 +287,11 @@ func buildImage(layers []*AttestationLayer, manifest *v1.Descriptor, subject *v1
 	// see note above - must be added after the layers!
 	if !opts.skipSubject {
 		subject.Platform = nil
-		newImg = mutate.Subject(newImg, *subject).(v1.Image)
+		ok := false
+		newImg, ok = mutate.Subject(newImg, *subject).(v1.Image)
+		if !ok {
+			return nil, fmt.Errorf("failed to set subject: %w", err)
+		}
 	}
 	if !opts.laxReferrers {
 		// as per https://github.com/opencontainers/image-spec/blob/main/manifest.md#guidance-for-an-empty-descriptor

pkg/attestation/example_attestation_manifest_test.go

@@ -14,7 +14,7 @@ import (
 	"github.com/in-toto/in-toto-golang/in_toto/slsa_provenance/common"
 )
 
-func ExampleAttestationManifest() {
+func ExampleManifest() {
 	// configure signerverifier
 	// local signer (unsafe for production)
 	signer, err := signerverifier.GenKeyPair()
@@ -55,7 +55,7 @@ func ExampleAttestationManifest() {
 				ID: "test-verifier",
 			},
 			TimeVerified:       time.Now().UTC().Format(time.RFC3339),
-			ResourceUri:        "some-uri",
+			ResourceURI:        "some-uri",
 			Policy:             attestation.VSAPolicy{URI: "some-uri"},
 			VerificationResult: "PASSED",
 			VerifiedLevels:     []string{"SLSA_BUILD_LEVEL_1"},

pkg/attestation/referrers_test.go

@@ -137,7 +137,7 @@ func TestAttestationReferenceTypes(t *testing.T) {
 					ref = fmt.Sprintf("%s/repo@%s", u.Host, idxDigest.String())
 				}
 
-				policyOpts := &policy.PolicyOptions{
+				policyOpts := &policy.Options{
 					LocalPolicyDir: LocalPolicy,
 				}
 
@@ -201,12 +201,12 @@ func TestReferencesInDifferentRepo(t *testing.T) {
 	} {
 		server := tc.server
 		defer server.Close()
-		serverUrl, err := url.Parse(server.URL)
+		serverURL, err := url.Parse(server.URL)
 		require.NoError(t, err)
 
 		refServer := tc.refServer
 		defer refServer.Close()
-		refServerUrl, err := url.Parse(refServer.URL)
+		refServerURL, err := url.Parse(refServer.URL)
 		require.NoError(t, err)
 
 		opts := &attestation.SigningOptions{
@@ -215,7 +215,7 @@ func TestReferencesInDifferentRepo(t *testing.T) {
 		attIdx, err := oci.IndexFromPath(UnsignedTestImage)
 		require.NoError(t, err)
 
-		indexName := fmt.Sprintf("%s/%s:latest", serverUrl.Host, repoName)
+		indexName := fmt.Sprintf("%s/%s:latest", serverURL.Host, repoName)
 		err = mirror.PushIndexToRegistry(attIdx.Index, indexName)
 		require.NoError(t, err)
 
@@ -227,12 +227,12 @@ func TestReferencesInDifferentRepo(t *testing.T) {
 			// push references using subject-digest.att convention
 			image, err := signedManifest.BuildAttestationImage()
 			require.NoError(t, err)
-			err = mirror.PushImageToRegistry(image, fmt.Sprintf("%s/%s:tag-does-not-matter", refServerUrl.Host, repoName))
+			err = mirror.PushImageToRegistry(image, fmt.Sprintf("%s/%s:tag-does-not-matter", refServerURL.Host, repoName))
 			require.NoError(t, err)
 
 			refServer := tc.refServer
 			defer refServer.Close()
-			refServerUrl, err := url.Parse(refServer.URL)
+			refServerURL, err := url.Parse(refServer.URL)
 			require.NoError(t, err)
 
 			opts := &attestation.SigningOptions{
@@ -241,7 +241,7 @@ func TestReferencesInDifferentRepo(t *testing.T) {
 			attIdx, err := oci.IndexFromPath(UnsignedTestImage)
 			require.NoError(t, err)
 
-			indexName := fmt.Sprintf("%s/%s:latest", serverUrl.Host, repoName)
+			indexName := fmt.Sprintf("%s/%s:latest", serverURL.Host, repoName)
 			err = mirror.PushIndexToRegistry(attIdx.Index, indexName)
 			require.NoError(t, err)
 
@@ -254,7 +254,7 @@ func TestReferencesInDifferentRepo(t *testing.T) {
 				imgs, err := mf.BuildReferringArtifacts()
 				require.NoError(t, err)
 				for _, img := range imgs {
-					err = mirror.PushImageToRegistry(img, fmt.Sprintf("%s/%s:tag-does-not-matter", refServerUrl.Host, repoName))
+					err = mirror.PushImageToRegistry(img, fmt.Sprintf("%s/%s:tag-does-not-matter", refServerURL.Host, repoName))
 					require.NoError(t, err)
 				}
 			}
@@ -267,7 +267,7 @@ func TestReferencesInDifferentRepo(t *testing.T) {
 				}
 				// can evaluate policy using referrers in a different repo
 				referencedImage := fmt.Sprintf("%s@%s", indexName, mf.Digest.String())
-				policyOpts := &policy.PolicyOptions{
+				policyOpts := &policy.Options{
 					LocalPolicyDir: PassPolicyDir,
 				}
 				src, err := oci.ParseImageSpec(referencedImage)
@@ -285,7 +285,7 @@ func TestCorrectArtifactTypeInTagFallback(t *testing.T) {
 	server := httptest.NewServer(registry.New())
 
 	defer server.Close()
-	serverUrl, err := url.Parse(server.URL)
+	serverURL, err := url.Parse(server.URL)
 	require.NoError(t, err)
 
 	repoName := "repo"
@@ -296,7 +296,7 @@ func TestCorrectArtifactTypeInTagFallback(t *testing.T) {
 	attIdx, err := oci.IndexFromPath(UnsignedTestImage)
 	require.NoError(t, err)
 
-	indexName := fmt.Sprintf("%s/%s:latest", serverUrl.Host, repoName)
+	indexName := fmt.Sprintf("%s/%s:latest", serverURL.Host, repoName)
 	err = mirror.PushIndexToRegistry(attIdx.Index, indexName)
 	require.NoError(t, err)
 
@@ -308,12 +308,12 @@ func TestCorrectArtifactTypeInTagFallback(t *testing.T) {
 		imgs, err := mf.BuildReferringArtifacts()
 		require.NoError(t, err)
 		for _, img := range imgs {
-			err = mirror.PushImageToRegistry(img, fmt.Sprintf("%s/%s:tag-does-not-matter", serverUrl.Host, repoName))
+			err = mirror.PushImageToRegistry(img, fmt.Sprintf("%s/%s:tag-does-not-matter", serverURL.Host, repoName))
 			require.NoError(t, err)
 			mf, err := img.Manifest()
 			require.NoError(t, err)
 			subject := mf.Subject
-			subjectRef, err := name.ParseReference(fmt.Sprintf("%s/%s:sha256-%s", serverUrl.Host, repoName, subject.Digest.Hex))
+			subjectRef, err := name.ParseReference(fmt.Sprintf("%s/%s:sha256-%s", serverURL.Host, repoName, subject.Digest.Hex))
 			require.NoError(t, err)
 			idx, err := remote.Index(subjectRef)
 			require.NoError(t, err)

pkg/attestation/sign.go

@@ -10,7 +10,7 @@ import (
 	"github.com/secure-systems-lab/go-securesystemslib/dsse"
 )
 
-// SignDSSE signs a payload with a given signer and uploads the signature to the transparency log
+// SignDSSE signs a payload with a given signer and uploads the signature to the transparency log.
 func SignDSSE(ctx context.Context, payload []byte, signer dsse.SignerVerifier, opts *SigningOptions) (*Envelope, error) {
 	payloadType := intoto.PayloadType
 	env := new(Envelope)
@@ -28,13 +28,13 @@ func SignDSSE(ctx context.Context, payload []byte, signer dsse.SignerVerifier, o
 	}
 
 	// get Key ID from signer
-	keyId, err := signer.KeyID()
+	keyID, err := signer.KeyID()
 	if err != nil {
 		return nil, fmt.Errorf("error getting public key ID: %w", err)
 	}
 
-	dsseSig := Signature{
-		KeyID: keyId,
+	dsseSig := &Signature{
+		KeyID: keyID,
 		Sig:   base64Encoding.EncodeToString(sig),
 	}
 	if !opts.SkipTL {
@@ -42,22 +42,22 @@ func SignDSSE(ctx context.Context, payload []byte, signer dsse.SignerVerifier, o
 		if err != nil {
 			return nil, fmt.Errorf("failed to log to rekor: %w", err)
 		}
-		dsseSig.Extension = *ext
+		dsseSig.Extension = ext
 	}
 	// add signature to dsse envelope
-	env.Signatures = []Signature{dsseSig}
+	env.Signatures = []*Signature{dsseSig}
 
 	return env, nil
 }
 
-// returns a new envelope with the transparency log entry added to the signature extension
+// returns a new envelope with the transparency log entry added to the signature extension.
 func logSignature(ctx context.Context, t tlog.TL, sig *[]byte, encPayload *[]byte, signer dsse.SignerVerifier) (*Extension, error) {
 	// get Key ID from signer
-	keyId, err := signer.KeyID()
+	keyID, err := signer.KeyID()
 	if err != nil {
 		return nil, fmt.Errorf("error getting public key ID: %w", err)
 	}
-	entry, err := t.UploadLogEntry(ctx, keyId, *encPayload, *sig, signer)
+	entry, err := t.UploadLogEntry(ctx, keyID, *encPayload, *sig, signer)
 	if err != nil {
 		return nil, fmt.Errorf("error uploading TL entry: %w", err)
 	}
@@ -66,10 +66,10 @@ func logSignature(ctx context.Context, t tlog.TL, sig *[]byte, encPayload *[]byt
 		return nil, fmt.Errorf("error unmarshaling tl entry: %w", err)
 	}
 	return &Extension{
-		Kind: DockerDsseExtKind,
-		Ext: DockerDsseExtension{
-			Tl: DockerTlExtension{
-				Kind: RekorTlExtKind,
+		Kind: DockerDSSEExtKind,
+		Ext: &DockerDSSEExtension{
+			TL: &DockerTLExtension{
+				Kind: RekorTLExtKind,
 				Data: entryObj, // transparency log entry metadata
 			},
 		},

pkg/attestation/sign_test.go

@@ -44,20 +44,20 @@ func TestSignVerifyAttestation(t *testing.T) {
 	// signer.Public() used here for test purposes
 	ecPub, ok := signer.Public().(*ecdsa.PublicKey)
 	assert.True(t, ok)
-	pem, err := signerverifier.ToPEM(ecPub)
+	pem, err := signerverifier.ConvertToPEM(ecPub)
 	assert.NoError(t, err)
-	keyId, err := signerverifier.KeyID(ecPub)
+	keyID, err := signerverifier.KeyID(ecPub)
 	assert.NoError(t, err)
 
 	badKeyPriv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
 	require.NoError(t, err)
 	badKey := &badKeyPriv.PublicKey
-	badPEM, err := signerverifier.ToPEM(badKey)
+	badPEM, err := signerverifier.ConvertToPEM(badKey)
 	require.NoError(t, err)
 
 	testCases := []struct {
 		name          string
-		keyId         string
+		keyID         string
 		pem           []byte
 		distrust      bool
 		from          time.Time
@@ -67,7 +67,7 @@ func TestSignVerifyAttestation(t *testing.T) {
 	}{
 		{
 			name:          "all OK",
-			keyId:         keyId,
+			keyID:         keyID,
 			pem:           pem,
 			distrust:      false,
 			from:          time.Time{},
@@ -77,17 +77,17 @@ func TestSignVerifyAttestation(t *testing.T) {
 		},
 		{
 			name:          "key not found",
-			keyId:         "someotherkey",
+			keyID:         "someotherkey",
 			pem:           pem,
 			distrust:      false,
 			from:          time.Time{},
 			to:            nil,
 			status:        "active",
-			expectedError: fmt.Sprintf("key not found: %s", keyId),
+			expectedError: fmt.Sprintf("key not found: %s", keyID),
 		},
 		{
 			name:          "key distrusted",
-			keyId:         keyId,
+			keyID:         keyID,
 			pem:           pem,
 			distrust:      true,
 			from:          time.Time{},
@@ -97,7 +97,7 @@ func TestSignVerifyAttestation(t *testing.T) {
 		},
 		{
 			name:          "key not yet valid",
-			keyId:         keyId,
+			keyID:         keyID,
 			pem:           pem,
 			distrust:      false,
 			from:          time.Now().Add(time.Hour),
@@ -107,7 +107,7 @@ func TestSignVerifyAttestation(t *testing.T) {
 		},
 		{
 			name:          "key already revoked",
-			keyId:         keyId,
+			keyID:         keyID,
 			pem:           pem,
 			distrust:      false,
 			from:          time.Time{},
@@ -117,7 +117,7 @@ func TestSignVerifyAttestation(t *testing.T) {
 		},
 		{
 			name:          "bad key",
-			keyId:         keyId,
+			keyID:         keyID,
 			pem:           badPEM,
 			distrust:      false,
 			from:          time.Time{},
@@ -129,8 +129,8 @@ func TestSignVerifyAttestation(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			keyMeta := attestation.KeyMetadata{
-				ID:       tc.keyId,
+			keyMeta := &attestation.KeyMetadata{
+				ID:       tc.keyID,
 				PEM:      string(tc.pem),
 				Distrust: tc.distrust,
 				From:     tc.from,

pkg/attestation/types.go

@@ -15,8 +15,8 @@ const (
 	AttestationManifestType       = "attestation-manifest"
 	InTotoPredicateType           = "in-toto.io/predicate-type"
 	DockerReferenceDigest         = "vnd.docker.reference.digest"
-	DockerDsseExtKind             = "application/vnd.docker.attestation-verification.v1+json"
-	RekorTlExtKind                = "Rekor"
+	DockerDSSEExtKind             = "application/vnd.docker.attestation-verification.v1+json"
+	RekorTLExtKind                = "Rekor"
 	OCIDescriptorDSSEMediaType    = ociv1.MediaTypeDescriptor + "+dsse"
 	InTotoReferenceLifecycleStage = "vnd.docker.lifecycle-stage"
 	LifecycleStageExperimental    = "experimental"
@@ -24,58 +24,58 @@ const (
 
 var base64Encoding = base64.StdEncoding.Strict()
 
-type AttestationLayer struct {
+type Layer struct {
 	Statement   *intoto.Statement
 	Layer       v1.Layer
 	Annotations map[string]string
 }
 
-type AttestationManifest struct {
+type Manifest struct {
 	OriginalDescriptor *v1.Descriptor
-	OriginalLayers     []*AttestationLayer
+	OriginalLayers     []*Layer
 
 	// accumulated during signing
-	SignedLayers []*AttestationLayer
+	SignedLayers []*Layer
 	// details of subect image
 	SubjectName       string
 	SubjectDescriptor *v1.Descriptor
 }
 
-type AttestationManifestImageOptions struct {
+type ManifestImageOptions struct {
 	// how to output the image
 	skipSubject   bool
 	replaceLayers bool
 	laxReferrers  bool
 }
 
-// the following types are needed until https://github.com/secure-systems-lab/dsse/pull/61 is merged
+// the following types are needed until https://github.com/secure-systems-lab/dsse/pull/61 is merged.
 type Envelope struct {
-	PayloadType string      `json:"payloadType"`
-	Payload     string      `json:"payload"`
-	Signatures  []Signature `json:"signatures"`
+	PayloadType string       `json:"payloadType"`
+	Payload     string       `json:"payload"`
+	Signatures  []*Signature `json:"signatures"`
 }
 type Signature struct {
-	KeyID     string    `json:"keyid"`
-	Sig       string    `json:"sig"`
-	Extension Extension `json:"extension,omitempty"`
+	KeyID     string     `json:"keyid"`
+	Sig       string     `json:"sig"`
+	Extension *Extension `json:"extension,omitempty"`
 }
 type Extension struct {
-	Kind string              `json:"kind"`
-	Ext  DockerDsseExtension `json:"ext"`
+	Kind string               `json:"kind"`
+	Ext  *DockerDSSEExtension `json:"ext"`
 }
 
-type DockerDsseExtension struct {
-	Tl DockerTlExtension `json:"tl"`
+type DockerDSSEExtension struct {
+	TL *DockerTLExtension `json:"tl"`
 }
 
-type DockerTlExtension struct {
+type DockerTLExtension struct {
 	Kind string `json:"kind"`
 	Data any    `json:"data"`
 }
 
 type VerifyOptions struct {
-	Keys   []KeyMetadata `json:"keys"`
-	SkipTL bool          `json:"skip_tl"`
+	Keys   []*KeyMetadata `json:"keys"`
+	SkipTL bool           `json:"skip_tl"`
 }
 
 type SigningOptions struct {

pkg/attestation/verify.go

@@ -28,8 +28,8 @@ type KeyMetadata struct {
 }
 
 type (
-	Keys    []KeyMetadata
-	KeysMap map[string]KeyMetadata
+	Keys    []*KeyMetadata
+	KeysMap map[string]*KeyMetadata
 )
 
 func VerifyDSSE(ctx context.Context, env *Envelope, opts *VerifyOptions) ([]byte, error) {
@@ -60,8 +60,8 @@ func VerifyDSSE(ctx context.Context, env *Envelope, opts *VerifyOptions) ([]byte
 	return payload, nil
 }
 
-func verifySignature(ctx context.Context, sig Signature, payload []byte, opts *VerifyOptions) error {
-	keys := make(map[string]KeyMetadata, len(opts.Keys))
+func verifySignature(ctx context.Context, sig *Signature, payload []byte, opts *VerifyOptions) error {
+	keys := make(map[string]*KeyMetadata, len(opts.Keys))
 	for _, key := range opts.Keys {
 		keys[key.ID] = key
 	}
@@ -74,26 +74,25 @@ func verifySignature(ctx context.Context, sig Signature, payload []byte, opts *V
 		return fmt.Errorf("key %s is distrusted", keyMeta.ID)
 	}
 	// TODO: this is unmarshalling with MarshalPKIXPublicKey only for us to marshal it again
-	publicKey, err := signerverifier.Parse([]byte(keyMeta.PEM))
+	publicKey, err := signerverifier.ParsePublicKey([]byte(keyMeta.PEM))
 	if err != nil {
 		return fmt.Errorf("failed to parse public key: %w", err)
 	}
 
 	if !opts.SkipTL {
 		t := tlog.GetTL(ctx)
-
-		if sig.Extension.Kind == "" {
-			return fmt.Errorf("error missing signature extension kind")
+		if sig.Extension == nil || sig.Extension.Kind == "" {
+			return fmt.Errorf("error missing signature extension")
 		}
-		if sig.Extension.Kind != DockerDsseExtKind {
+		if sig.Extension.Kind != DockerDSSEExtKind {
 			return fmt.Errorf("error unsupported signature extension kind: %s", sig.Extension.Kind)
 		}
 
 		// verify TL entry
-		if sig.Extension.Ext.Tl.Kind != RekorTlExtKind {
-			return fmt.Errorf("error unsupported TL extension kind: %s", sig.Extension.Ext.Tl.Kind)
+		if sig.Extension.Ext.TL.Kind != RekorTLExtKind {
+			return fmt.Errorf("error unsupported TL extension kind: %s", sig.Extension.Ext.TL.Kind)
 		}
-		entry := sig.Extension.Ext.Tl.Data
+		entry := sig.Extension.Ext.TL.Data
 		entryBytes, err := json.Marshal(entry)
 		if err != nil {
 			return fmt.Errorf("failed to marshal TL entry: %w", err)

pkg/attestation/verify_test.go

@@ -35,7 +35,7 @@ func TestVerifyUnsignedAttestation(t *testing.T) {
 	payload := []byte("payload")
 	env := &attestation.Envelope{
 		// no signatures
-		Signatures:  []attestation.Signature{},
+		Signatures:  []*attestation.Signature{},
 		Payload:     base64.StdEncoding.EncodeToString(payload),
 		PayloadType: intoto.PayloadType,
 	}

pkg/attestation/vsa.go

@@ -14,7 +14,7 @@ const (
 type VSAPredicate struct {
 	Verifier           VSAVerifier           `json:"verifier"`
 	TimeVerified       string                `json:"timeVerified"`
-	ResourceUri        string                `json:"resourceUri"`
+	ResourceURI        string                `json:"resourceUri"`
 	Policy             VSAPolicy             `json:"policy"`
 	InputAttestations  []VSAInputAttestation `json:"inputAttestations"`
 	VerificationResult string                `json:"verificationResult"`

pkg/config/config.go

@@ -31,7 +31,7 @@ func LoadLocalMappings(configDir string) (*PolicyMappings, error) {
 	return expandMappingFile(mappings)
 }
 
-func LoadTufMappings(tufClient tuf.TUFClient, localTargetsDir string) (*PolicyMappings, error) {
+func LoadTUFMappings(tufClient tuf.Downloader, localTargetsDir string) (*PolicyMappings, error) {
 	if tufClient == nil {
 		return nil, fmt.Errorf("tuf client not set")
 	}
@@ -52,7 +52,7 @@ func LoadTufMappings(tufClient tuf.TUFClient, localTargetsDir string) (*PolicyMa
 func expandMappingFile(mappingFile *policyMappingsFile) (*PolicyMappings, error) {
 	policies := make(map[string]*PolicyMapping)
 	for _, policy := range mappingFile.Policies {
-		policies[policy.Id] = policy
+		policies[policy.ID] = policy
 	}
 
 	var rules []*PolicyRule
@@ -63,7 +63,7 @@ func expandMappingFile(mappingFile *policyMappingsFile) (*PolicyMappings, error)
 		}
 		rules = append(rules, &PolicyRule{
 			Pattern:     r,
-			PolicyId:    rule.PolicyId,
+			PolicyID:    rule.PolicyID,
 			Replacement: rule.Replacement,
 		})
 	}

pkg/config/types.go

@@ -13,7 +13,7 @@ type policyMappingsFile struct {
 
 type policyRuleFile struct {
 	Pattern     string `json:"pattern"`
-	PolicyId    string `json:"policy-id"`
+	PolicyID    string `json:"policy-id"`
 	Replacement string `json:"rewrite"`
 }
 
@@ -32,7 +32,7 @@ const (
 )
 
 type PolicyMapping struct {
-	Id           string              `json:"id"`
+	ID           string              `json:"id"`
 	Description  string              `json:"description"`
 	Files        []PolicyMappingFile `json:"files"`
 	Attestations *AttestationConfig  `json:"attestations"`
@@ -49,6 +49,6 @@ type PolicyMappingFile struct {
 
 type PolicyRule struct {
 	Pattern     *regexp.Regexp
-	PolicyId    string
+	PolicyID    string
 	Replacement string
 }

pkg/mirror/example_mirror_test.go

@@ -14,12 +14,12 @@ import (
 
 type TufMirrorOutput struct {
 	metadata          v1.Image
-	delegatedMetadata []*mirror.MirrorImage
-	targets           []*mirror.MirrorImage
-	delegatedTargets  []*mirror.MirrorIndex
+	delegatedMetadata []*mirror.Image
+	targets           []*mirror.Image
+	delegatedTargets  []*mirror.Index
 }
 
-func ExampleNewTufMirror() {
+func ExampleNewTUFMirror() {
 	home, err := os.UserHomeDir()
 	if err != nil {
 		panic(err)
@@ -29,7 +29,7 @@ func ExampleNewTufMirror() {
 	// configure TUF mirror
 	metadataURI := "https://docker.github.io/tuf-staging/metadata"
 	targetsURI := "https://docker.github.io/tuf-staging/targets"
-	m, err := mirror.NewTufMirror(embed.RootStaging.Data, tufOutputPath, metadataURI, targetsURI, tuf.NewMockVersionChecker())
+	m, err := mirror.NewTUFMirror(embed.RootStaging.Data, tufOutputPath, metadataURI, targetsURI, tuf.NewMockVersionChecker())
 	if err != nil {
 		panic(err)
 	}
@@ -46,7 +46,7 @@ func ExampleNewTufMirror() {
 	}
 
 	// create targets manifest
-	targets, err := m.GetTufTargetMirrors()
+	targets, err := m.GetTUFTargetMirrors()
 	if err != nil {
 		panic(err)
 	}

pkg/mirror/metadata.go

@@ -16,9 +16,9 @@ import (
 // TUF root metadata
 // -----------------
 
-// GetMetadataManifest returns an image with TUF root metadata as layers
-func (m *TufMirror) GetMetadataManifest(metadataURL string) (v1.Image, error) {
-	metadata, err := m.getTufMetadataMirror(metadataURL)
+// GetMetadataManifest returns an image with TUF root metadata as layers.
+func (m *TUFMirror) GetMetadataManifest(metadataURL string) (v1.Image, error) {
+	metadata, err := m.getMetadataMirror(metadataURL)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get metadata: %w", err)
 	}
@@ -29,16 +29,16 @@ func (m *TufMirror) GetMetadataManifest(metadataURL string) (v1.Image, error) {
 	return manifest, nil
 }
 
-// getTufMetadataMirror returns a TufMetadata struct with TUF metadata as map of file names to bytes
-func (m *TufMirror) getTufMetadataMirror(metadataURL string) (*TufMetadata, error) {
-	trustedMetadata := m.TufClient.GetMetadata()
+// getMetadataMirror returns a TufMetadata struct with TUF metadata as map of file names to bytes.
+func (m *TUFMirror) getMetadataMirror(metadataURL string) (*TUFMetadata, error) {
+	trustedMetadata := m.TUFClient.GetMetadata()
 
 	rootMetadata := map[string][]byte{}
 	rootVersion := trustedMetadata.Root.Signed.Version
 	// get the previous versions of root metadata if any
 	if rootVersion != 1 {
 		var err error
-		rootMetadata, err = m.TufClient.GetPriorRoots(metadataURL)
+		rootMetadata, err = m.TUFClient.GetPriorRoots(metadataURL)
 		if err != nil {
 			return nil, fmt.Errorf("failed to get prior root metadata: %w", err)
 		}
@@ -69,7 +69,7 @@ func (m *TufMirror) getTufMetadataMirror(metadataURL string) (*TufMetadata, erro
 		snapshotVersion = strconv.FormatInt(trustedMetadata.Snapshot.Signed.Version, 10)
 		targetsVersion = strconv.FormatInt(trustedMetadata.Targets[metadata.TARGETS].Signed.Version, 10)
 	}
-	return &TufMetadata{
+	return &TUFMetadata{
 		Root:      rootMetadata,
 		Snapshot:  map[string][]byte{nameFromRole(metadata.SNAPSHOT, snapshotVersion): snapshotBytes},
 		Targets:   map[string][]byte{nameFromRole(metadata.TARGETS, targetsVersion): targetsBytes},
@@ -77,12 +77,12 @@ func (m *TufMirror) getTufMetadataMirror(metadataURL string) (*TufMetadata, erro
 	}, nil
 }
 
-// buildMetadataManifest returns an OCI image with TUF metadata as layers with annotations
-func (m *TufMirror) buildMetadataManifest(metadata *TufMetadata) (v1.Image, error) {
+// buildMetadataManifest returns an OCI image with TUF metadata as layers with annotations.
+func (m *TUFMirror) buildMetadataManifest(metadata *TUFMetadata) (v1.Image, error) {
 	img := empty.Image
 	img = mutate.MediaType(img, types.OCIManifestSchema1)
 	img = mutate.ConfigMediaType(img, types.OCIConfigJSON)
-	for _, role := range TufRoles {
+	for _, role := range TUFRoles {
 		layers, err := m.makeRoleLayers(role, metadata)
 		if err != nil {
 			return nil, fmt.Errorf("failed to make role layer: %w", err)
@@ -95,8 +95,8 @@ func (m *TufMirror) buildMetadataManifest(metadata *TufMetadata) (v1.Image, erro
 	return img, nil
 }
 
-// makeRoleLayers returns a list of layers for a given TUF role
-func (m *TufMirror) makeRoleLayers(role TufRole, tufMetadata *TufMetadata) ([]mutate.Addendum, error) {
+// makeRoleLayers returns a list of layers for a given TUF role.
+func (m *TUFMirror) makeRoleLayers(role TUFRole, tufMetadata *TUFMetadata) ([]mutate.Addendum, error) {
 	var layers []mutate.Addendum
 	ann := map[string]string{tufFileAnnotation: ""}
 	switch role {
@@ -115,8 +115,8 @@ func (m *TufMirror) makeRoleLayers(role TufRole, tufMetadata *TufMetadata) ([]mu
 	return layers, nil
 }
 
-// annotatedMetaLayers returns a list of layers with annotations for each TUF metadata file
-func (m *TufMirror) annotatedMetaLayers(meta map[string][]byte) []mutate.Addendum {
+// annotatedMetaLayers returns a list of layers with annotations for each TUF metadata file.
+func (m *TUFMirror) annotatedMetaLayers(meta map[string][]byte) []mutate.Addendum {
 	var layers []mutate.Addendum
 	for name, data := range meta {
 		ann := map[string]string{tufFileAnnotation: name}
@@ -129,8 +129,8 @@ func (m *TufMirror) annotatedMetaLayers(meta map[string][]byte) []mutate.Addendu
 // TUF delegated targets metadata
 // ------------------------------
 
-// GetDelegatedMetadataMirrors returns a list of mirrors (image/tag pairs) for each delegated targets role metadata
-func (m *TufMirror) GetDelegatedMetadataMirrors() ([]*MirrorImage, error) {
+// GetDelegatedMetadataMirrors returns a list of mirrors (image/tag pairs) for each delegated targets role metadata.
+func (m *TUFMirror) GetDelegatedMetadataMirrors() ([]*Image, error) {
 	// get current delegated targets metadata
 	delegatedTargets, err := m.getDelegatedTargetsMetadata()
 	if err != nil {
@@ -143,12 +143,12 @@ func (m *TufMirror) GetDelegatedMetadataMirrors() ([]*MirrorImage, error) {
 	return mirror, nil
 }
 
-// getDelegatedTargetsMetadata returns delegated targets metadata as a list of DelegatedTargetMetadata (role name and data)
-func (m *TufMirror) getDelegatedTargetsMetadata() ([]DelegatedTargetMetadata, error) {
+// getDelegatedTargetsMetadata returns delegated targets metadata as a list of DelegatedTargetMetadata (role name and data).
+func (m *TUFMirror) getDelegatedTargetsMetadata() ([]DelegatedTargetMetadata, error) {
 	var delegatedTargets []DelegatedTargetMetadata
-	md := m.TufClient.GetMetadata()
+	md := m.TUFClient.GetMetadata()
 	for _, role := range md.Targets[metadata.TARGETS].Signed.Delegations.Roles {
-		roleMetadata, err := m.TufClient.LoadDelegatedTargets(role.Name, metadata.TARGETS)
+		roleMetadata, err := m.TUFClient.LoadDelegatedTargets(role.Name, metadata.TARGETS)
 		if err != nil {
 			return nil, fmt.Errorf("failed to get delegated role metadata: %w", err)
 		}
@@ -170,9 +170,9 @@ func (m *TufMirror) getDelegatedTargetsMetadata() ([]DelegatedTargetMetadata, er
 	return delegatedTargets, nil
 }
 
-// buildDelegatedMetadataManifests returns a list of mirrors (image/tag pairs) for each delegated target role metadata
-func (m *TufMirror) buildDelegatedMetadataManifests(delegated []DelegatedTargetMetadata) ([]*MirrorImage, error) {
-	manifests := []*MirrorImage{}
+// buildDelegatedMetadataManifests returns a list of mirrors (image/tag pairs) for each delegated target role metadata.
+func (m *TUFMirror) buildDelegatedMetadataManifests(delegated []DelegatedTargetMetadata) ([]*Image, error) {
+	manifests := []*Image{}
 	for _, role := range delegated {
 		img := empty.Image
 		img = mutate.MediaType(img, types.OCIManifestSchema1)
@@ -183,7 +183,7 @@ func (m *TufMirror) buildDelegatedMetadataManifests(delegated []DelegatedTargetM
 		if err != nil {
 			return nil, fmt.Errorf("failed to append delegated targets layer to image: %w", err)
 		}
-		manifests = append(manifests, &MirrorImage{Image: img, Tag: role.Name})
+		manifests = append(manifests, &Image{Image: img, Tag: role.Name})
 	}
 	return manifests, nil
 }

pkg/mirror/metadata_test.go

@@ -21,10 +21,10 @@ func TestGetTufMetadataMirror(t *testing.T) {
 	defer server.Close()
 
 	path := test.CreateTempDir(t, "", "tuf_temp")
-	m, err := NewTufMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
+	m, err := NewTUFMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
 	assert.NoError(t, err)
 
-	tufMetadata, err := m.getTufMetadataMirror(server.URL + "/metadata")
+	tufMetadata, err := m.getMetadataMirror(server.URL + "/metadata")
 	assert.NoError(t, err)
 
 	// check that all roles are not empty
@@ -39,7 +39,7 @@ func TestGetMetadataManifest(t *testing.T) {
 	defer server.Close()
 
 	path := test.CreateTempDir(t, "", "tuf_temp")
-	m, err := NewTufMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
+	m, err := NewTUFMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
 	assert.NoError(t, err)
 
 	img, err := m.GetMetadataManifest(server.URL + "/metadata")
@@ -78,7 +78,7 @@ func TestGetDelegatedMetadataMirrors(t *testing.T) {
 	defer server.Close()
 
 	path := test.CreateTempDir(t, "", "tuf_temp")
-	m, err := NewTufMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
+	m, err := NewTUFMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
 	assert.NoError(t, err)
 
 	delegations, err := m.GetDelegatedMetadataMirrors()

pkg/mirror/mirror.go

@@ -16,15 +16,15 @@ import (
 	"github.com/google/go-containerregistry/pkg/v1/remote"
 )
 
-func NewTufMirror(root []byte, tufPath, metadataURL, targetsURL string, versionChecker tuf.VersionChecker) (*TufMirror, error) {
+func NewTUFMirror(root []byte, tufPath, metadataURL, targetsURL string, versionChecker tuf.VersionChecker) (*TUFMirror, error) {
 	if root == nil {
 		root = embed.RootDefault.Data
 	}
-	tufClient, err := tuf.NewTufClient(root, tufPath, metadataURL, targetsURL, versionChecker)
+	tufClient, err := tuf.NewClient(root, tufPath, metadataURL, targetsURL, versionChecker)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create TUF client: %w", err)
 	}
-	return &TufMirror{TufClient: tufClient, tufPath: tufPath, metadataURL: metadataURL, targetsURL: targetsURL}, nil
+	return &TUFMirror{TUFClient: tufClient, tufPath: tufPath, metadataURL: metadataURL, targetsURL: targetsURL}, nil
 }
 
 func PushImageToRegistry(image v1.Image, imageName string) error {
@@ -85,7 +85,7 @@ func SaveIndex(outputs []*oci.ImageSpec, index v1.ImageIndex, indexName string)
 				Add: index,
 				Descriptor: v1.Descriptor{
 					Annotations: map[string]string{
-						oci.OciReferenceTarget: indexName,
+						oci.OCIReferenceTarget: indexName,
 					},
 				},
 			})
@@ -110,7 +110,7 @@ func SaveImage(output *oci.ImageSpec, image v1.Image, imageName string) error {
 			Add: image,
 			Descriptor: v1.Descriptor{
 				Annotations: map[string]string{
-					oci.OciReferenceTarget: imageName,
+					oci.OCIReferenceTarget: imageName,
 				},
 			},
 		})
@@ -127,7 +127,7 @@ func SaveImage(output *oci.ImageSpec, image v1.Image, imageName string) error {
 	return nil
 }
 
-func SaveReferrers(manifest *attestation.AttestationManifest, outputs []*oci.ImageSpec) error {
+func SaveReferrers(manifest *attestation.Manifest, outputs []*oci.ImageSpec) error {
 	for _, output := range outputs {
 		if output.Type == oci.OCI {
 			continue

pkg/mirror/targets.go

@@ -13,16 +13,16 @@ import (
 	"github.com/theupdateframework/go-tuf/v2/metadata"
 )
 
-// GetTufTargetMirrors returns a list of top-level target files as MirrorImages (image with tag)
-func (m *TufMirror) GetTufTargetMirrors() ([]*MirrorImage, error) {
-	targetMirrors := []*MirrorImage{}
-	md := m.TufClient.GetMetadata()
+// GetTUFTargetMirrors returns a list of top-level target files as MirrorImages (image with tag).
+func (m *TUFMirror) GetTUFTargetMirrors() ([]*Image, error) {
+	targetMirrors := []*Image{}
+	md := m.TUFClient.GetMetadata()
 
 	// for each top-level target file, create an image with the target file as a layer
 	targets := md.Targets[metadata.TARGETS].Signed.Targets
 	for _, t := range targets {
 		// download target file
-		_, data, err := m.TufClient.DownloadTarget(t.Path, filepath.Join(m.tufPath, "download"))
+		_, data, err := m.TUFClient.DownloadTarget(t.Path, filepath.Join(m.tufPath, "download"))
 		if err != nil {
 			return nil, fmt.Errorf("failed to download target %s: %w", t.Path, err)
 		}
@@ -42,16 +42,16 @@ func (m *TufMirror) GetTufTargetMirrors() ([]*MirrorImage, error) {
 		if err != nil {
 			return nil, fmt.Errorf("failed to append role layer to image: %w", err)
 		}
-		targetMirrors = append(targetMirrors, &MirrorImage{Image: img, Tag: name})
+		targetMirrors = append(targetMirrors, &Image{Image: img, Tag: name})
 	}
 	return targetMirrors, nil
 }
 
 // GetDelegatedTargetMirrors returns a list of delegated target files as MirrorIndexes (image index with tag)
-// each image in the index contains a delegated target file
-func (m *TufMirror) GetDelegatedTargetMirrors() ([]*MirrorIndex, error) {
-	mirror := []*MirrorIndex{}
-	md := m.TufClient.GetMetadata()
+// each image in the index contains a delegated target file.
+func (m *TUFMirror) GetDelegatedTargetMirrors() ([]*Index, error) {
+	mirror := []*Index{}
+	md := m.TUFClient.GetMetadata()
 
 	// for each delegated role, create an image index with target files as images
 	roles := md.Targets[metadata.TARGETS].Signed.Delegations.Roles
@@ -60,7 +60,7 @@ func (m *TufMirror) GetDelegatedTargetMirrors() ([]*MirrorIndex, error) {
 		index := v1.ImageIndex(empty.Index)
 
 		// get delegated targets metadata for role
-		roleMeta, err := m.TufClient.LoadDelegatedTargets(role.Name, metadata.TARGETS)
+		roleMeta, err := m.TUFClient.LoadDelegatedTargets(role.Name, metadata.TARGETS)
 		if err != nil {
 			return nil, fmt.Errorf("failed to load delegated targets metadata: %w", err)
 		}
@@ -68,7 +68,7 @@ func (m *TufMirror) GetDelegatedTargetMirrors() ([]*MirrorIndex, error) {
 		// for each target file, create an image with the target file as a layer
 		for _, target := range roleMeta.Signed.Targets {
 			// download target file
-			_, data, err := m.TufClient.DownloadTarget(target.Path, filepath.Join(m.tufPath, "download"))
+			_, data, err := m.TUFClient.DownloadTarget(target.Path, filepath.Join(m.tufPath, "download"))
 			if err != nil {
 				return nil, fmt.Errorf("failed to download target %s: %w", target.Path, err)
 			}
@@ -103,7 +103,7 @@ func (m *TufMirror) GetDelegatedTargetMirrors() ([]*MirrorIndex, error) {
 				},
 			})
 		}
-		mirror = append(mirror, &MirrorIndex{Index: index, Tag: role.Name})
+		mirror = append(mirror, &Index{Index: index, Tag: role.Name})
 	}
 	return mirror, nil
 }

pkg/mirror/targets_test.go

@@ -27,10 +27,10 @@ func TestGetTufTargetsMirror(t *testing.T) {
 	defer server.Close()
 
 	path := test.CreateTempDir(t, "", "tuf_temp")
-	m, err := NewTufMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
+	m, err := NewTUFMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
 	assert.NoError(t, err)
 
-	targets, err := m.GetTufTargetMirrors()
+	targets, err := m.GetTUFTargetMirrors()
 	assert.NoError(t, err)
 	assert.Greater(t, len(targets), 0)
 
@@ -61,10 +61,10 @@ func TestTargetDelegationMetadata(t *testing.T) {
 	defer server.Close()
 
 	path := test.CreateTempDir(t, "", "tuf_temp")
-	tm, err := NewTufMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
+	tm, err := NewTUFMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
 	assert.NoError(t, err)
 
-	targets, err := tm.TufClient.LoadDelegatedTargets("test-role", "targets")
+	targets, err := tm.TUFClient.LoadDelegatedTargets("test-role", "targets")
 	assert.NoError(t, err)
 	assert.Greater(t, len(targets.Signed.Targets), 0)
 }
@@ -74,7 +74,7 @@ func TestGetDelegatedTargetMirrors(t *testing.T) {
 	defer server.Close()
 
 	path := test.CreateTempDir(t, "", "tuf_temp")
-	m, err := NewTufMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
+	m, err := NewTUFMirror(embed.RootDev.Data, path, server.URL+"/metadata", server.URL+"/targets", tuf.NewMockVersionChecker())
 	assert.NoError(t, err)
 
 	mirrors, err := m.GetDelegatedTargetMirrors()

pkg/mirror/types.go

@@ -14,11 +14,11 @@ const (
 	tufFileAnnotation    = "tuf.io/filename"
 )
 
-type TufRole string
+type TUFRole string
 
-var TufRoles = []TufRole{metadata.ROOT, metadata.SNAPSHOT, metadata.TARGETS, metadata.TIMESTAMP}
+var TUFRoles = []TUFRole{metadata.ROOT, metadata.SNAPSHOT, metadata.TARGETS, metadata.TIMESTAMP}
 
-type TufMetadata struct {
+type TUFMetadata struct {
 	Root      map[string][]byte
 	Snapshot  map[string][]byte
 	Targets   map[string][]byte
@@ -31,18 +31,18 @@ type DelegatedTargetMetadata struct {
 	Data    []byte
 }
 
-type MirrorImage struct {
+type Image struct {
 	Image v1.Image
 	Tag   string
 }
 
-type MirrorIndex struct {
+type Index struct {
 	Index v1.ImageIndex
 	Tag   string
 }
 
-type TufMirror struct {
-	TufClient   *tuf.TufClient
+type TUFMirror struct {
+	TUFClient   *tuf.Client
 	tufPath     string
 	metadataURL string
 	targetsURL  string

pkg/oci/http.go

@@ -7,21 +7,21 @@ import (
 )
 
 type userAgentTransporter struct {
-	ua string
-	rt http.RoundTripper
+	userAgent    string
+	roundTripper http.RoundTripper
 }
 
 type Option = func(*http.Client)
 
 func (u *userAgentTransporter) RoundTrip(req *http.Request) (*http.Response, error) {
-	req.Header.Set("User-Agent", u.ua)
+	req.Header.Set("User-Agent", u.userAgent)
 
-	return u.rt.RoundTrip(req)
+	return u.roundTripper.RoundTrip(req)
 }
 
-func HttpTransport() http.RoundTripper {
+func HTTPTransport() http.RoundTripper {
 	return &userAgentTransporter{
-		ua: "Docker-Client",
-		rt: cleanhttp.DefaultTransport(),
+		userAgent:    "Docker-Client",
+		roundTripper: cleanhttp.DefaultTransport(),
 	}
 }

pkg/oci/layout.go

@@ -11,14 +11,14 @@ import (
 	"github.com/google/go-containerregistry/pkg/v1/layout"
 )
 
-// implementation of AttestationResolver that closes over attestations from an oci layout
-type OCILayoutResolver struct {
-	*attestation.AttestationManifest
+// implementation of AttestationResolver that closes over attestations from an oci layout.
+type LayoutResolver struct {
+	*attestation.Manifest
 	*ImageSpec
 }
 
-func NewOCILayoutAttestationResolver(src *ImageSpec) (*OCILayoutResolver, error) {
-	r := &OCILayoutResolver{
+func NewOCILayoutAttestationResolver(src *ImageSpec) (*LayoutResolver, error) {
+	r := &LayoutResolver{
 		ImageSpec: src,
 	}
 	_, err := r.fetchAttestationManifest()
@@ -28,25 +28,25 @@ func NewOCILayoutAttestationResolver(src *ImageSpec) (*OCILayoutResolver, error)
 	return r, nil
 }
 
-func (r *OCILayoutResolver) fetchAttestationManifest() (*attestation.AttestationManifest, error) {
-	if r.AttestationManifest == nil {
+func (r *LayoutResolver) fetchAttestationManifest() (*attestation.Manifest, error) {
+	if r.Manifest == nil {
 		m, err := attestationManifestFromOCILayout(r.Identifier, r.ImageSpec.Platform)
 		if err != nil {
 			return nil, err
 		}
-		r.AttestationManifest = m
+		r.Manifest = m
 	}
 
-	return r.AttestationManifest, nil
+	return r.Manifest, nil
 }
 
-func (r *OCILayoutResolver) Attestations(ctx context.Context, predicateType string) ([]*att.Envelope, error) {
+func (r *LayoutResolver) Attestations(_ context.Context, predicateType string) ([]*att.Envelope, error) {
 	var envs []*att.Envelope
 	dsseMediaType, err := attestation.DSSEMediaType(predicateType)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get DSSE media type for predicate '%s': %w", predicateType, err)
 	}
-	for _, attestationLayer := range r.AttestationManifest.OriginalLayers {
+	for _, attestationLayer := range r.Manifest.OriginalLayers {
 		mt, err := attestationLayer.Layer.MediaType()
 		if err != nil {
 			return nil, fmt.Errorf("failed to get layer media type: %w", err)
@@ -71,19 +71,19 @@ func (r *OCILayoutResolver) Attestations(ctx context.Context, predicateType stri
 	return envs, nil
 }
 
-func (r *OCILayoutResolver) ImageName(ctx context.Context) (string, error) {
+func (r *LayoutResolver) ImageName(_ context.Context) (string, error) {
 	return r.SubjectName, nil
 }
 
-func (r *OCILayoutResolver) ImageDescriptor(ctx context.Context) (*v1.Descriptor, error) {
+func (r *LayoutResolver) ImageDescriptor(_ context.Context) (*v1.Descriptor, error) {
 	return r.SubjectDescriptor, nil
 }
 
-func (r *OCILayoutResolver) ImagePlatform(ctx context.Context) (*v1.Platform, error) {
+func (r *LayoutResolver) ImagePlatform(_ context.Context) (*v1.Platform, error) {
 	return r.ImageSpec.Platform, nil
 }
 
-func attestationManifestFromOCILayout(path string, platform *v1.Platform) (*attestation.AttestationManifest, error) {
+func attestationManifestFromOCILayout(path string, platform *v1.Platform) (*attestation.Manifest, error) {
 	idx, err := layout.ImageIndexFromPath(path)
 	if err != nil {
 		return nil, err
@@ -107,13 +107,15 @@ func attestationManifestFromOCILayout(path string, platform *v1.Platform) (*atte
 		return nil, fmt.Errorf("failed to extract IndexManifest from ImageIndex: %w", err)
 	}
 	var subjectDescriptor *v1.Descriptor
-	for _, mf := range mfs2.Manifests {
-		if mf.Platform.Equals(*platform) {
-			subjectDescriptor = &mf
+	for i := range mfs2.Manifests {
+		manifest := &mfs2.Manifests[i]
+		if manifest.Platform.Equals(*platform) {
+			subjectDescriptor = manifest
 			break
 		}
 	}
-	for _, mf := range mfs2.Manifests {
+	for i := range mfs2.Manifests {
+		mf := &mfs2.Manifests[i]
 		if mf.Annotations[att.DockerReferenceType] != attestation.AttestationManifestType {
 			continue
 		}
@@ -130,9 +132,9 @@ func attestationManifestFromOCILayout(path string, platform *v1.Platform) (*atte
 		if err != nil {
 			return nil, fmt.Errorf("failed to get attestations from image: %w", err)
 		}
-		attest := &attestation.AttestationManifest{
+		attest := &attestation.Manifest{
 			OriginalLayers:     layers,
-			OriginalDescriptor: &mf,
+			OriginalDescriptor: mf,
 			SubjectName:        name,
 			SubjectDescriptor:  subjectDescriptor,
 		}

pkg/oci/oci.go

@@ -18,7 +18,7 @@ import (
 )
 
 // ParsePlatform parses the provided platform string or attempts to obtain
-// the platform of the current host system
+// the platform of the current host system.
 func ParsePlatform(platformStr string) (*v1.Platform, error) {
 	if platformStr == "" {
 		cdp := platforms.Normalize(platforms.DefaultSpec())
@@ -30,14 +30,13 @@ func ParsePlatform(platformStr string) (*v1.Platform, error) {
 			Architecture: cdp.Architecture,
 			Variant:      cdp.Variant,
 		}, nil
-	} else {
-		return v1.ParsePlatform(platformStr)
 	}
+	return v1.ParsePlatform(platformStr)
 }
 
 func WithOptions(ctx context.Context, platform *v1.Platform) []remote.Option {
 	// prepare options
-	options := []remote.Option{MultiKeychainOption(), remote.WithTransport(HttpTransport()), remote.WithContext(ctx)}
+	options := []remote.Option{MultiKeychainOption(), remote.WithTransport(HTTPTransport()), remote.WithContext(ctx)}
 
 	// add in platform into remote Get operation; this might conflict with an explicit digest, but we are trying anyway
 	if platform != nil {
@@ -46,7 +45,7 @@ func WithOptions(ctx context.Context, platform *v1.Platform) []remote.Option {
 	return options
 }
 
-func ExtractEnvelopes(manifest *attestation.AttestationManifest, predicateType string) ([]*att.Envelope, error) {
+func ExtractEnvelopes(manifest *attestation.Manifest, predicateType string) ([]*att.Envelope, error) {
 	var envs []*att.Envelope
 	dsseMediaType, err := attestation.DSSEMediaType(predicateType)
 	if err != nil {
@@ -76,16 +75,18 @@ func ExtractEnvelopes(manifest *attestation.AttestationManifest, predicateType s
 }
 
 func imageDescriptor(ix *v1.IndexManifest, platform *v1.Platform) (*v1.Descriptor, error) {
-	for _, m := range ix.Manifests {
+	for i := range ix.Manifests {
+		m := &ix.Manifests[i]
 		if (m.MediaType == ocispec.MediaTypeImageManifest || m.MediaType == "application/vnd.docker.distribution.manifest.v2+json") && m.Platform.Equals(*platform) {
-			return &m, nil
+			return m, nil
 		}
 	}
 	return nil, fmt.Errorf("no image found for platform %v", platform)
 }
 
 func attestationDigestForDigest(ix *v1.IndexManifest, imageDigest string, attestType string) (string, error) {
-	for _, m := range ix.Manifests {
+	for i := range ix.Manifests {
+		m := &ix.Manifests[i]
 		if v, ok := m.Annotations[att.DockerReferenceType]; ok && v == attestType {
 			if d, ok := m.Annotations[att.DockerReferenceDigest]; ok && d == imageDigest {
 				return m.Digest.String(), nil
@@ -160,7 +161,7 @@ func ReplaceTagInSpec(src *ImageSpec, digest v1.Hash) (*ImageSpec, error) {
 	}, nil
 }
 
-// so that the index tag is replaced with a tag unique to the image digest and doesn't overwrite it
+// so that the index tag is replaced with a tag unique to the image digest and doesn't overwrite it.
 func replaceTag(image string, digest v1.Hash) (string, error) {
 	if strings.HasPrefix(image, LocalPrefix) {
 		return image, nil

pkg/oci/referrers.go

@@ -35,7 +35,7 @@ func WithReferrersRepo(repo string) func(*ReferrersResolver) error {
 	}
 }
 
-func (r *ReferrersResolver) resolveAttestations(ctx context.Context, predicateType string) ([]*attestation.AttestationManifest, error) {
+func (r *ReferrersResolver) resolveAttestations(ctx context.Context, predicateType string) ([]*attestation.Manifest, error) {
 	dsseMediaType, err := attestation.DSSEMediaType(predicateType)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get DSSE media type for predicate '%s': %w", predicateType, err)
@@ -75,8 +75,9 @@ func (r *ReferrersResolver) resolveAttestations(ctx context.Context, predicateTy
 	if err != nil {
 		return nil, fmt.Errorf("failed to get index manifest: %w", err)
 	}
-	aManifests := make([]*attestation.AttestationManifest, 0)
-	for _, m := range referrersIndexManifest.Manifests {
+	aManifests := make([]*attestation.Manifest, 0)
+	for i := range referrersIndexManifest.Manifests {
+		m := referrersIndexManifest.Manifests[i]
 		remoteRef := referrersSubjectRef.Context().Digest(m.Digest.String())
 		options = WithOptions(ctx, nil)
 		attestationImage, err := remote.Image(remoteRef, options...)
@@ -97,7 +98,7 @@ func (r *ReferrersResolver) resolveAttestations(ctx context.Context, predicateTy
 		if string(mt) != dsseMediaType {
 			return nil, fmt.Errorf("expected layer media type %s, got %s", dsseMediaType, mt)
 		}
-		attest := &attestation.AttestationManifest{
+		attest := &attestation.Manifest{
 			SubjectName:        imageName,
 			OriginalLayers:     layers,
 			OriginalDescriptor: &m,

pkg/oci/registry.go

@@ -13,7 +13,7 @@ import (
 
 type RegistryResolver struct {
 	*RegistryImageDetailsResolver
-	*attestation.AttestationManifest
+	*attestation.Manifest
 }
 
 type RegistryImageDetailsResolver struct {
@@ -33,11 +33,11 @@ func NewRegistryAttestationResolver(src *RegistryImageDetailsResolver) (*Registr
 	}, nil
 }
 
-func (r *RegistryImageDetailsResolver) ImageName(ctx context.Context) (string, error) {
+func (r *RegistryImageDetailsResolver) ImageName(_ context.Context) (string, error) {
 	return r.Identifier, nil
 }
 
-func (r *RegistryImageDetailsResolver) ImagePlatform(ctx context.Context) (*v1.Platform, error) {
+func (r *RegistryImageDetailsResolver) ImagePlatform(_ context.Context) (*v1.Platform, error) {
 	return r.Platform, nil
 }
 
@@ -74,17 +74,17 @@ func (r *RegistryImageDetailsResolver) ImageDescriptor(ctx context.Context) (*v1
 }
 
 func (r *RegistryResolver) Attestations(ctx context.Context, predicateType string) ([]*att.Envelope, error) {
-	if r.AttestationManifest == nil {
+	if r.Manifest == nil {
 		attest, err := FetchAttestationManifest(ctx, r.Identifier, r.ImageSpec.Platform)
 		if err != nil {
 			return nil, err
 		}
-		r.AttestationManifest = attest
+		r.Manifest = attest
 	}
-	return ExtractEnvelopes(r.AttestationManifest, predicateType)
+	return ExtractEnvelopes(r.Manifest, predicateType)
 }
 
-func FetchAttestationManifest(ctx context.Context, image string, platform *v1.Platform) (*attestation.AttestationManifest, error) {
+func FetchAttestationManifest(ctx context.Context, image string, platform *v1.Platform) (*attestation.Manifest, error) {
 	// we want to get to the image index, so ignoring platform for now
 	options := WithOptions(ctx, nil)
 	ref, err := name.ParseReference(image)
@@ -131,7 +131,7 @@ func FetchAttestationManifest(ctx context.Context, image string, platform *v1.Pl
 	if err != nil {
 		return nil, fmt.Errorf("failed to get attestations from image: %w", err)
 	}
-	attest := &attestation.AttestationManifest{
+	attest := &attestation.Manifest{
 		OriginalLayers:     layers,
 		OriginalDescriptor: &remoteDescriptor.Descriptor,
 		SubjectName:        image,

pkg/oci/types.go

@@ -11,7 +11,7 @@ import (
 )
 
 const (
-	OciReferenceTarget            = "org.opencontainers.image.ref.name"
+	OCIReferenceTarget            = "org.opencontainers.image.ref.name"
 	LocalPrefix                   = "oci://"
 	RegistryPrefix                = "docker://"
 	OCI                SourceType = "OCI"
@@ -52,7 +52,7 @@ func IndexFromPath(path string) (*NamedIndex, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to get digest: %w", err)
 	}
-	imageName := idxm.Manifests[0].Annotations[OciReferenceTarget]
+	imageName := idxm.Manifests[0].Annotations[OCIReferenceTarget]
 	idxDigest := idxm.Manifests[0].Digest
 
 	idx, err := wrapperIdx.ImageIndex(idxDigest)
@@ -85,9 +85,8 @@ func IndexFromRemote(image string) (*NamedIndex, error) {
 func LoadIndex(input *ImageSpec) (*NamedIndex, error) {
 	if input.Type == OCI {
 		return IndexFromPath(input.Identifier)
-	} else {
-		return IndexFromRemote(input.Identifier)
 	}
+	return IndexFromRemote(input.Identifier)
 }
 
 func (i *ImageSpec) ForPlatforms(platform string) ([]*ImageSpec, error) {

pkg/policy/evaluator.go

@@ -11,20 +11,20 @@ type policyEvaluatorCtxKeyType struct{}
 
 var PolicyEvaluatorCtxKey policyEvaluatorCtxKeyType
 
-// sets PolicyEvaluator in context
-func WithPolicyEvaluator(ctx context.Context, pe PolicyEvaluator) context.Context {
+// sets PolicyEvaluator in context.
+func WithPolicyEvaluator(ctx context.Context, pe Evaluator) context.Context {
 	return context.WithValue(ctx, PolicyEvaluatorCtxKey, pe)
 }
 
-// gets PolicyEvaluator from context, defaults to Rego PolicyEvaluator if not set
-func GetPolicyEvaluator(ctx context.Context) (PolicyEvaluator, error) {
-	t, ok := ctx.Value(PolicyEvaluatorCtxKey).(PolicyEvaluator)
+// gets PolicyEvaluator from context, defaults to Rego PolicyEvaluator if not set.
+func GetPolicyEvaluator(ctx context.Context) (Evaluator, error) {
+	t, ok := ctx.Value(PolicyEvaluatorCtxKey).(Evaluator)
 	if !ok {
 		return nil, fmt.Errorf("no policy evaluator client set on context (set one with policy.WithPolicyEvaluator)")
 	}
 	return t, nil
 }
 
-type PolicyEvaluator interface {
-	Evaluate(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *PolicyInput) (*Result, error)
+type Evaluator interface {
+	Evaluate(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *Input) (*Result, error)
 }

pkg/policy/mock.go

@@ -7,19 +7,19 @@ import (
 )
 
 type MockPolicyEvaluator struct {
-	EvaluateFunc func(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *PolicyInput) (*Result, error)
+	EvaluateFunc func(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *Input) (*Result, error)
 }
 
-func (pe *MockPolicyEvaluator) Evaluate(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *PolicyInput) (*Result, error) {
+func (pe *MockPolicyEvaluator) Evaluate(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *Input) (*Result, error) {
 	if pe.EvaluateFunc != nil {
 		return pe.EvaluateFunc(ctx, resolver, pctx, input)
 	}
 	return AllowedResult(), nil
 }
 
-func GetMockPolicy() PolicyEvaluator {
+func GetMockPolicy() Evaluator {
 	return &MockPolicyEvaluator{
-		EvaluateFunc: func(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *PolicyInput) (*Result, error) {
+		EvaluateFunc: func(_ context.Context, _ oci.AttestationResolver, _ *Policy, _ *Input) (*Result, error) {
 			return AllowedResult(), nil
 		},
 	}

pkg/policy/policy.go

@@ -12,11 +12,11 @@ import (
 	"github.com/docker/attest/pkg/oci"
 )
 
-func resolveLocalPolicy(opts *PolicyOptions, mapping *config.PolicyMapping, imageName string, matchedName string) (*Policy, error) {
+func resolveLocalPolicy(opts *Options, mapping *config.PolicyMapping, imageName string, matchedName string) (*Policy, error) {
 	if opts.LocalPolicyDir == "" {
 		return nil, fmt.Errorf("local policy dir not set")
 	}
-	files := make([]*PolicyFile, 0, len(mapping.Files))
+	files := make([]*File, 0, len(mapping.Files))
 	for _, f := range mapping.Files {
 		filename := f.Path
 		filePath := path.Join(opts.LocalPolicyDir, filename)
@@ -24,7 +24,7 @@ func resolveLocalPolicy(opts *PolicyOptions, mapping *config.PolicyMapping, imag
 		if err != nil {
 			return nil, fmt.Errorf("failed to read policy file %s: %w", filename, err)
 		}
-		files = append(files, &PolicyFile{
+		files = append(files, &File{
 			Path:    filename,
 			Content: fileContents,
 		})
@@ -39,15 +39,15 @@ func resolveLocalPolicy(opts *PolicyOptions, mapping *config.PolicyMapping, imag
 	return policy, nil
 }
 
-func resolveTufPolicy(opts *PolicyOptions, mapping *config.PolicyMapping, imageName string, matchedName string) (*Policy, error) {
-	files := make([]*PolicyFile, 0, len(mapping.Files))
+func resolveTUFPolicy(opts *Options, mapping *config.PolicyMapping, imageName string, matchedName string) (*Policy, error) {
+	files := make([]*File, 0, len(mapping.Files))
 	for _, f := range mapping.Files {
 		filename := f.Path
-		_, fileContents, err := opts.TufClient.DownloadTarget(filename, filepath.Join(opts.LocalTargetsDir, filename))
+		_, fileContents, err := opts.TUFClient.DownloadTarget(filename, filepath.Join(opts.LocalTargetsDir, filename))
 		if err != nil {
 			return nil, fmt.Errorf("failed to download policy file %s: %w", filename, err)
 		}
-		files = append(files, &PolicyFile{
+		files = append(files, &File{
 			Path:    filename,
 			Content: fileContents,
 		})
@@ -88,12 +88,12 @@ func findPolicyMatchImpl(imageName string, mappings *config.PolicyMappings, matc
 	for _, rule := range mappings.Rules {
 		if rule.Pattern.MatchString(imageName) {
 			switch {
-			case rule.PolicyId == "" && rule.Replacement == "":
+			case rule.PolicyID == "" && rule.Replacement == "":
 				return nil, fmt.Errorf("rule %s has neither policy-id nor rewrite", rule.Pattern)
-			case rule.PolicyId != "" && rule.Replacement != "":
+			case rule.PolicyID != "" && rule.Replacement != "":
 				return nil, fmt.Errorf("rule %s has both policy-id and rewrite", rule.Pattern)
-			case rule.PolicyId != "":
-				policy := mappings.Policies[rule.PolicyId]
+			case rule.PolicyID != "":
+				policy := mappings.Policies[rule.PolicyID]
 				if policy != nil {
 					return &policyMatch{
 						matchType:   matchTypePolicy,
@@ -120,35 +120,35 @@ func findPolicyMatchImpl(imageName string, mappings *config.PolicyMappings, matc
 	return &policyMatch{matchType: matchTypeNoMatch, matchedName: imageName}, nil
 }
 
-func resolvePolicyById(opts *PolicyOptions) (*Policy, error) {
-	if opts.PolicyId != "" {
+func resolvePolicyByID(opts *Options) (*Policy, error) {
+	if opts.PolicyID != "" {
 		localMappings, err := config.LoadLocalMappings(opts.LocalPolicyDir)
 		if err != nil {
 			return nil, fmt.Errorf("failed to load local policy mappings: %w", err)
 		}
 		if localMappings != nil {
-			policy := localMappings.Policies[opts.PolicyId]
+			policy := localMappings.Policies[opts.PolicyID]
 			if policy != nil {
 				return resolveLocalPolicy(opts, policy, "", "")
 			}
 		}
 
 		// must check tuf
-		tufMappings, err := config.LoadTufMappings(opts.TufClient, opts.LocalTargetsDir)
+		tufMappings, err := config.LoadTUFMappings(opts.TUFClient, opts.LocalTargetsDir)
 		if err != nil {
 			return nil, fmt.Errorf("failed to load tuf policy mappings by id: %w", err)
 		}
-		policy := tufMappings.Policies[opts.PolicyId]
+		policy := tufMappings.Policies[opts.PolicyID]
 		if policy != nil {
-			return resolveTufPolicy(opts, policy, "", "")
+			return resolveTUFPolicy(opts, policy, "", "")
 		}
-		return nil, fmt.Errorf("policy with id %s not found", opts.PolicyId)
+		return nil, fmt.Errorf("policy with id %s not found", opts.PolicyID)
 	}
 	return nil, nil
 }
 
-func ResolvePolicy(ctx context.Context, detailsResolver oci.ImageDetailsResolver, opts *PolicyOptions) (*Policy, error) {
-	p, err := resolvePolicyById(opts)
+func ResolvePolicy(ctx context.Context, detailsResolver oci.ImageDetailsResolver, opts *Options) (*Policy, error) {
+	p, err := resolvePolicyByID(opts)
 	if err != nil {
 		return nil, fmt.Errorf("failed to resolve policy by id: %w", err)
 	}
@@ -175,7 +175,7 @@ func ResolvePolicy(ctx context.Context, detailsResolver oci.ImageDetailsResolver
 		return resolveLocalPolicy(opts, match.policy, imageName, match.matchedName)
 	}
 	// must check tuf
-	tufMappings, err := config.LoadTufMappings(opts.TufClient, opts.LocalTargetsDir)
+	tufMappings, err := config.LoadTUFMappings(opts.TUFClient, opts.LocalTargetsDir)
 	if err != nil {
 		return nil, fmt.Errorf("failed to load tuf policy mappings as fallback: %w", err)
 	}
@@ -183,8 +183,8 @@ func ResolvePolicy(ctx context.Context, detailsResolver oci.ImageDetailsResolver
 	// it's a mirror of a tuf policy
 	if match.matchType == matchTypeMatchNoPolicy {
 		for _, mapping := range tufMappings.Policies {
-			if mapping.Id == match.rule.PolicyId {
-				return resolveTufPolicy(opts, mapping, imageName, match.matchedName)
+			if mapping.ID == match.rule.PolicyID {
+				return resolveTUFPolicy(opts, mapping, imageName, match.matchedName)
 			}
 		}
 	}
@@ -195,7 +195,7 @@ func ResolvePolicy(ctx context.Context, detailsResolver oci.ImageDetailsResolver
 		return nil, err
 	}
 	if match.matchType == matchTypePolicy {
-		return resolveTufPolicy(opts, match.policy, imageName, match.matchedName)
+		return resolveTUFPolicy(opts, match.policy, imageName, match.matchedName)
 	}
 	return nil, nil
 }
@@ -229,7 +229,7 @@ func CreateAttestationResolver(resolver oci.ImageDetailsResolver, mapping *confi
 			}
 			return oci.NewReferrersAttestationResolver(resolver)
 		}
-	case *oci.OCILayoutResolver:
+	case *oci.LayoutResolver:
 		if mapping.Attestations != nil && mapping.Attestations.Style == config.AttestationStyleAttached {
 			return resolver, nil
 		} else {

pkg/policy/policy_match_test.go

@@ -112,7 +112,7 @@ func TestFindPolicyMatch(t *testing.T) {
 			assert.Equal(t, tc.expectedMatchType, match.matchType)
 			if match.matchType == matchTypePolicy {
 				if assert.NotNil(t, match.policy) {
-					assert.Equal(t, tc.expectedPolicyID, match.policy.Id)
+					assert.Equal(t, tc.expectedPolicyID, match.policy.ID)
 				}
 			}
 			assert.Equal(t, tc.expectedImageName, match.matchedName)

pkg/policy/policy_test.go

@@ -47,13 +47,13 @@ func TestRegoEvaluator_Evaluate(t *testing.T) {
 		expectSuccess bool
 		isCanonical   bool
 		resolver      oci.AttestationResolver
-		policy        *policy.PolicyOptions
-		policyId      string
+		policy        *policy.Options
+		policyID      string
 		errorStr      string
 	}{
 		{repo: "testdata/mock-tuf-allow", expectSuccess: true, isCanonical: false, resolver: defaultResolver},
-		{repo: "testdata/mock-tuf-allow", expectSuccess: true, isCanonical: false, resolver: defaultResolver, policyId: "docker-official-images"},
-		{repo: "testdata/mock-tuf-allow", expectSuccess: false, isCanonical: false, resolver: defaultResolver, policyId: "non-existent-policy-id", errorStr: errorStr},
+		{repo: "testdata/mock-tuf-allow", expectSuccess: true, isCanonical: false, resolver: defaultResolver, policyID: "docker-official-images"},
+		{repo: "testdata/mock-tuf-allow", expectSuccess: false, isCanonical: false, resolver: defaultResolver, policyID: "non-existent-policy-id", errorStr: errorStr},
 		{repo: "testdata/mock-tuf-deny", expectSuccess: false, isCanonical: false, resolver: defaultResolver},
 		{repo: "testdata/mock-tuf-verify-sig", expectSuccess: true, isCanonical: false, resolver: defaultResolver},
 		{repo: "testdata/mock-tuf-wrong-key", expectSuccess: false, isCanonical: false, resolver: defaultResolver},
@@ -63,18 +63,18 @@ func TestRegoEvaluator_Evaluate(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.repo, func(t *testing.T) {
-			input := &policy.PolicyInput{
+			input := &policy.Input{
 				Digest:      "sha256:test-digest",
-				Purl:        "test-purl",
+				PURL:        "test-purl",
 				IsCanonical: tc.isCanonical,
 			}
 
 			tufClient := tuf.NewMockTufClient(tc.repo, test.CreateTempDir(t, "", "tuf-dest"))
 			if tc.policy == nil {
-				tc.policy = &policy.PolicyOptions{
-					TufClient:       tufClient,
+				tc.policy = &policy.Options{
+					TUFClient:       tufClient,
 					LocalTargetsDir: test.CreateTempDir(t, "", "tuf-targets"),
-					PolicyId:        tc.policyId,
+					PolicyID:        tc.policyID,
 				}
 			}
 			imageName, err := tc.resolver.ImageName(ctx)
@@ -110,8 +110,8 @@ func TestLoadingMappings(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, len(policyMappings.Rules), 3)
 	for _, mirror := range policyMappings.Rules {
-		if mirror.PolicyId != "" {
-			assert.Equal(t, "docker-official-images", mirror.PolicyId)
+		if mirror.PolicyID != "" {
+			assert.Equal(t, "docker-official-images", mirror.PolicyID)
 		}
 	}
 }

pkg/policy/rego.go

@@ -30,13 +30,13 @@ const (
 	resultBinding = "result"
 )
 
-func NewRegoEvaluator(debug bool) PolicyEvaluator {
+func NewRegoEvaluator(debug bool) Evaluator {
 	return &regoEvaluator{
 		debug: debug,
 	}
 }
 
-func (re *regoEvaluator) Evaluate(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *PolicyInput) (*Result, error) {
+func (re *regoEvaluator) Evaluate(ctx context.Context, resolver oci.AttestationResolver, pctx *Policy, input *Input) (*Result, error) {
 	var regoOpts []func(*rego.Rego)
 
 	// Create a new in-memory store
@@ -113,7 +113,7 @@ func (re *regoEvaluator) Evaluate(ctx context.Context, resolver oci.AttestationR
 }
 
 func jsonGenerator[T any]() func(t *ast.Term, ec *rego.EvalContext) (any, error) {
-	return func(t *ast.Term, ec *rego.EvalContext) (any, error) {
+	return func(t *ast.Term, _ *rego.EvalContext) (any, error) {
 		// TODO: this is horrible - we're converting the AST to JSON and then back to AST, then using ast.As to convert it to a struct
 		// We can't use ast.As directly because it fails if the AST contains a set
 		json, err := ast.JSON(t.Value)
@@ -164,9 +164,9 @@ func handleErrors1(f func(rCtx rego.BuiltinContext, a *ast.Term) (*ast.Term, err
 	}
 }
 
-func handleErrors2(f func(rCtx rego.BuiltinContext, a, b *ast.Term) (*ast.Term, error)) rego.Builtin2 {
+func handleErrors2(f func(rCtx *rego.BuiltinContext, a, b *ast.Term) (*ast.Term, error)) rego.Builtin2 {
 	return func(rCtx rego.BuiltinContext, a, b *ast.Term) (*ast.Term, error) {
-		return wrapFunctionResult(f(rCtx, a, b))
+		return wrapFunctionResult(f(&rCtx, a, b))
 	}
 }
 
@@ -181,7 +181,7 @@ func RegoFunctions(resolver oci.AttestationResolver) []*tester.Builtin {
 					Memoize:          true,
 					Nondeterministic: verifyDecl.Nondeterministic,
 				},
-				handleErrors2(verifyIntotoEnvelope)),
+				handleErrors2(verifyInTotoEnvelope)),
 		},
 		{
 			Decl: attestDecl,
@@ -192,12 +192,12 @@ func RegoFunctions(resolver oci.AttestationResolver) []*tester.Builtin {
 					Memoize:          true,
 					Nondeterministic: attestDecl.Nondeterministic,
 				},
-				handleErrors1(fetchIntotoAttestations(resolver))),
+				handleErrors1(fetchInTotoAttestations(resolver))),
 		},
 	}
 }
 
-func fetchIntotoAttestations(resolver oci.AttestationResolver) rego.Builtin1 {
+func fetchInTotoAttestations(resolver oci.AttestationResolver) rego.Builtin1 {
 	return func(rCtx rego.BuiltinContext, predicateTypeTerm *ast.Term) (*ast.Term, error) {
 		predicateTypeStr, ok := predicateTypeTerm.Value.(ast.String)
 		if !ok {
@@ -227,7 +227,7 @@ func fetchIntotoAttestations(resolver oci.AttestationResolver) rego.Builtin1 {
 	}
 }
 
-func verifyIntotoEnvelope(rCtx rego.BuiltinContext, envTerm, optsTerm *ast.Term) (*ast.Term, error) {
+func verifyInTotoEnvelope(rCtx *rego.BuiltinContext, envTerm, optsTerm *ast.Term) (*ast.Term, error) {
 	env := new(att.Envelope)
 	opts := new(att.VerifyOptions)
 	err := ast.As(envTerm.Value, env)

pkg/policy/types.go

@@ -26,29 +26,29 @@ type Result struct {
 	Summary    Summary     `json:"summary"`
 }
 
-type PolicyOptions struct {
-	TufClient        tuf.TUFClient
+type Options struct {
+	TUFClient        tuf.Downloader
 	LocalTargetsDir  string
 	LocalPolicyDir   string
-	PolicyId         string
+	PolicyID         string
 	ReferrersRepo    string
 	AttestationStyle config.AttestationStyle
 }
 
 type Policy struct {
-	InputFiles   []*PolicyFile
+	InputFiles   []*File
 	Query        string
 	Mapping      *config.PolicyMapping
 	ResolvedName string
 }
 
-type PolicyInput struct {
+type Input struct {
 	Digest      string `json:"digest"`
-	Purl        string `json:"purl"`
+	PURL        string `json:"purl"`
 	IsCanonical bool   `json:"isCanonical"`
 }
 
-type PolicyFile struct {
+type File struct {
 	Path    string
 	Content []byte
 }

pkg/signerverifier/aws.go

@@ -9,18 +9,18 @@ import (
 	awssigner "github.com/sigstore/sigstore/pkg/signature/kms/aws"
 )
 
-// using AWS KMS
-func GetAWSSigner(ctx context.Context, keyArn string, region string) (dsse.SignerVerifier, error) {
-	keypath := fmt.Sprintf("awskms:///%s", keyArn)
-	sv, err := awssigner.LoadSignerVerifier(ctx, keypath, config.WithRegion(region))
+// using AWS KMS.
+func GetAWSSigner(ctx context.Context, keyARN string, region string) (dsse.SignerVerifier, error) {
+	keyPath := fmt.Sprintf("awskms:///%s", keyARN)
+	sv, err := awssigner.LoadSignerVerifier(ctx, keyPath, config.WithRegion(region))
 	if err != nil {
 		return nil, fmt.Errorf("error loading aws signer verifier: %w", err)
 	}
-	cs, _, err := sv.CryptoSigner(context.Background(), func(err error) {})
+	cs, _, err := sv.CryptoSigner(context.Background(), func(_ error) {})
 	if err != nil {
 		return nil, fmt.Errorf("error getting aws crypto signer: %w", err)
 	}
-	signer := &ECDSA256_SignerVerifier{
+	signer := &ECDSA256SignerVerifier{
 		Signer: cs,
 	}
 	return signer, nil

pkg/signerverifier/common.go

@@ -14,12 +14,12 @@ import (
 	"github.com/secure-systems-lab/go-securesystemslib/dsse"
 )
 
-type ECDSA256_SignerVerifier struct {
+type ECDSA256SignerVerifier struct {
 	crypto.Signer
 }
 
-// implement keyid function
-func (s *ECDSA256_SignerVerifier) KeyID() (string, error) {
+// implement keyid function.
+func (s *ECDSA256SignerVerifier) KeyID() (string, error) {
 	keyid, err := KeyID(s.Signer.Public())
 	if err != nil {
 		return "", fmt.Errorf("error getting keyid: %w", err)
@@ -27,15 +27,15 @@ func (s *ECDSA256_SignerVerifier) KeyID() (string, error) {
 	return keyid, nil
 }
 
-func (s *ECDSA256_SignerVerifier) Public() crypto.PublicKey {
+func (s *ECDSA256SignerVerifier) Public() crypto.PublicKey {
 	return s.Signer.Public()
 }
 
-func (s *ECDSA256_SignerVerifier) Sign(ctx context.Context, data []byte) ([]byte, error) {
+func (s *ECDSA256SignerVerifier) Sign(_ context.Context, data []byte) ([]byte, error) {
 	return s.Signer.Sign(rand.Reader, data, crypto.SHA256)
 }
 
-func (s *ECDSA256_SignerVerifier) Verify(ctx context.Context, data []byte, sig []byte) error {
+func (s *ECDSA256SignerVerifier) Verify(_ context.Context, data []byte, sig []byte) error {
 	pub, ok := s.Signer.Public().(*ecdsa.PublicKey)
 	if !ok {
 		return fmt.Errorf("public key is not ecdsa")
@@ -52,7 +52,7 @@ func LoadKeyPair(priv []byte) (dsse.SignerVerifier, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &ECDSA256_SignerVerifier{
+	return &ECDSA256SignerVerifier{
 		Signer: privateKey,
 	}, nil
 }
@@ -78,7 +78,7 @@ func GenKeyPair() (dsse.SignerVerifier, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &ECDSA256_SignerVerifier{
+	return &ECDSA256SignerVerifier{
 		Signer: signer,
 	}, nil
 }

pkg/signerverifier/gcp.go

@@ -10,18 +10,18 @@ import (
 )
 
 // using GCP KMS
-// reference should be in the format projects/[PROJECT_ID]/locations/[LOCATION]/keyRings/[KEY_RING]/cryptoKeys/[KEY]/cryptoKeyVersions/[VERSION]
+// reference should be in the format projects/[PROJECT_ID]/locations/[LOCATION]/keyRings/[KEY_RING]/cryptoKeys/[KEY]/cryptoKeyVersions/[VERSION].
 func GetGCPSigner(ctx context.Context, reference string, opts ...option.ClientOption) (dsse.SignerVerifier, error) {
 	reference = fmt.Sprintf("gcpkms://%s", reference)
 	sv, err := gcpsigner.LoadSignerVerifier(ctx, reference, opts...)
 	if err != nil {
 		return nil, fmt.Errorf("error loading gcp signer verifier: %w", err)
 	}
-	cs, _, err := sv.CryptoSigner(ctx, func(err error) {})
+	cs, _, err := sv.CryptoSigner(ctx, func(_ error) {})
 	if err != nil {
 		return nil, fmt.Errorf("error getting gcp crypto signer: %w", err)
 	}
-	signer := &ECDSA256_SignerVerifier{
+	signer := &ECDSA256SignerVerifier{
 		Signer: cs,
 	}
 	return signer, nil

pkg/signerverifier/gcp_test.go

@@ -37,7 +37,7 @@ func TestGCPKMS_Signer(t *testing.T) {
 	keyId, err := signer.KeyID()
 	require.NoError(t, err)
 	assert.NotEmpty(t, keyId)
-	publicKey, err := Parse([]byte(publicKeyPEM))
+	publicKey, err := ParsePublicKey([]byte(publicKeyPEM))
 	require.NoError(t, err)
 	// verify payload ecdsa signature
 	ok := ecdsa.VerifyASN1(publicKey, hash, sig)

pkg/signerverifier/keyid.go

@@ -11,7 +11,7 @@ import (
 func KeyID(pubKey crypto.PublicKey) (string, error) {
 	pub, err := x509.MarshalPKIXPublicKey(pubKey)
 	if err != nil {
-		return "", fmt.Errorf("error marshalling public key: %w", err)
+		return "", fmt.Errorf("error marshaling public key: %w", err)
 	}
 	return util.SHA256Hex(pub), nil
 }

pkg/signerverifier/parse.go

@@ -9,7 +9,7 @@ import (
 
 const pemType = "PUBLIC KEY"
 
-func Parse(pubkeyBytes []byte) (*ecdsa.PublicKey, error) {
+func ParsePublicKey(pubkeyBytes []byte) (*ecdsa.PublicKey, error) {
 	p, _ := pem.Decode(pubkeyBytes)
 	if p == nil {
 		return nil, fmt.Errorf("pubkey file does not contain any PEM data")
@@ -29,7 +29,7 @@ func Parse(pubkeyBytes []byte) (*ecdsa.PublicKey, error) {
 	return ecdsaPubKey, nil
 }
 
-func ToPEM(ecdsaPubKey *ecdsa.PublicKey) ([]byte, error) {
+func ConvertToPEM(ecdsaPubKey *ecdsa.PublicKey) ([]byte, error) {
 	pubKeyBytes, err := x509.MarshalPKIXPublicKey(ecdsaPubKey)
 	if err != nil {
 		return nil, fmt.Errorf("error failed to marshal public key: %w", err)

pkg/tlog/mock.go

@@ -10,7 +10,7 @@ import (
 )
 
 const (
-	USE_MOCK_TL = true
+	UseMockTL = true
 
 	TestEntry = `{"body":"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","integratedTime":1703705039,"logID":"c0d23d6ad406973f9559f3ba2d1ca01f84147d8ffc5b8445c224f98b9591801d","logIndex":59674396,"verification":{"inclusionProof":{"checkpoint":"rekor.sigstore.dev - 2605736670972794746\n55510966\nJCi1O53Xmdi9lXnui4Q5SQ+MJSMnWr1Bxn+Q2Qf22tU=\nTimestamp: 1703705040158839214\n\n— rekor.sigstore.dev wNI9ajBFAiAXgtjFDVqCSgiSP04TQzELrz4+EyBwyYVL2EEULTCy0AIhAI9peLU76ZUD1tvU8qvzBJBo77IYD1rc+A1MPc35AeVK\n","hashes":["fb77ee213b48f4b18dc81c6e634c570abf99b257713561f174f2e0f4c039af67","6cb113bbefadecbbb8b89b1c08232438a6125071790b6a062cff8c1ccfdcb91e","6fbe1424e264e4590ca502d671b7a036c87f7a90d1f57534b98eb781144160bf","077b606720a6478200f6c3ed08a68e9b01b1cae192cb120888ddcc95521601bd","b6f8e8bc21ae0cde82b92422a4b4f37b28a43185821e468a4e65b6c79ed8f5b7","89332533fac54e9bc68c7353c42f6ebb9fe38039f67910332ff95082072068d4","0814d6f707a75fb3334bab14ab5466bd8b9a64ae7be7cd4d53a428c64932bc66","e883e826f10329c63a4a2ed21156037a050df43b9d74079296beac6968ed4150","d79230703257b7e4a8a61b032b6980d1a0bdbc7ae96ca838b525b3751785fe48","2f4a77e5288462cd3b75084d37f1502dcbe0943d18dd95cb247fc1ebbabc0aad","38562c253d3536d0d00e3547c880b6b0251a25ac69605b50c9eaa1a27186cc7a","9dea192350ff8b3c0f5ccda38261cb38ebd61869281c3928912332d1144e0a04","2c4d25ba59aa573ab2c79c2d3cd9e1d74789b10632432724d63112ce50b44874","98c486feb5d87092a78a46c4b5be04868654900affc2e86ffb20074dc73a883a","6969c49bd73f19bf28a5eaeabd331ddd60502defb2cd3d96e17b741c80adec6c"],"logIndex":55510965,"rootHash":"2428b53b9dd799d8bd9579ee8b8439490f8c2523275abd41c67f90d907f6dad5","treeSize":55510966},"signedEntryTimestamp":"MEUCIQCG9PRI8PcvtJyE9pbcculZipze6NEWR1Nk8EYocto3BwIgYu5gqgjW80HMjSjUxUNJLp0wlVTesnJCeByUBySc59w="}}`
 )
@@ -26,10 +26,10 @@ func GetMockTL() TL {
 	}
 
 	return &MockTL{
-		UploadLogEntryFunc: func(ctx context.Context, subject string, payload []byte, signature []byte, signer dsse.SignerVerifier) ([]byte, error) {
+		UploadLogEntryFunc: func(_ context.Context, _ string, _ []byte, _ []byte, _ dsse.SignerVerifier) ([]byte, error) {
 			return []byte(TestEntry), nil
 		},
-		VerifyLogEntryFunc: func(ctx context.Context, entryBytes []byte) (time.Time, error) {
+		VerifyLogEntryFunc: func(_ context.Context, entryBytes []byte) (time.Time, error) {
 			// return the integrated time in the log entry without any checking
 			le, err := unmarshalEntry(entryBytes)
 			if err != nil {
@@ -40,7 +40,7 @@ func GetMockTL() TL {
 			}
 			return time.Unix(*le.IntegratedTime, 0), nil
 		},
-		VerifyEntryPayloadFunc: func(entryBytes, payload, pkToken []byte) error {
+		VerifyEntryPayloadFunc: func(_, _, _ []byte) error {
 			return nil
 		},
 		UnmarshalEntryFunc: func(entry []byte) (any, error) {

pkg/tlog/tl.go

@@ -1,6 +1,7 @@
 package tlog
 
 import (
+	"bytes"
 	"context"
 	"crypto/rand"
 	"crypto/sha256"
@@ -31,23 +32,23 @@ const (
 
 type tlCtxKeyType struct{}
 
-var TlCtxKey tlCtxKeyType
+var TLCtxKey tlCtxKeyType
 
-// sets TL in context
+// sets TL in context.
 func WithTL(ctx context.Context, tl TL) context.Context {
-	return context.WithValue(ctx, TlCtxKey, tl)
+	return context.WithValue(ctx, TLCtxKey, tl)
 }
 
-// gets TL from context, defaults to Rekor TL if not set
+// gets TL from context, defaults to Rekor TL if not set.
 func GetTL(ctx context.Context) TL {
-	t, ok := ctx.Value(TlCtxKey).(TL)
+	t, ok := ctx.Value(TLCtxKey).(TL)
 	if !ok {
 		t = &RekorTL{}
 	}
 	return t
 }
 
-type TlPayload struct {
+type TLPayload struct {
 	Algorithm string
 	Hash      string
 	Signature string
@@ -98,7 +99,7 @@ func (tl *MockTL) UnmarshalEntry(entryBytes []byte) (any, error) {
 
 type RekorTL struct{}
 
-// UploadLogEntry submits a PK token signature to the transparency log
+// UploadLogEntry submits a PK token signature to the transparency log.
 func (tl *RekorTL) UploadLogEntry(ctx context.Context, subject string, payload, signature []byte, signer dsse.SignerVerifier) ([]byte, error) {
 	// generate self-signed x509 cert
 	pubCert, err := CreateX509Cert(subject, signer)
@@ -121,12 +122,12 @@ func (tl *RekorTL) UploadLogEntry(ctx context.Context, subject string, payload,
 	}
 	entryBytes, err := entry.MarshalBinary()
 	if err != nil {
-		return nil, fmt.Errorf("error marshalling TL entry: %w", err)
+		return nil, fmt.Errorf("error marshaling TL entry: %w", err)
 	}
 	return entryBytes, nil
 }
 
-// VerifyLogEntry verifies a transparency log entry
+// VerifyLogEntry verifies a transparency log entry.
 func (tl *RekorTL) VerifyLogEntry(ctx context.Context, entryBytes []byte) (time.Time, error) {
 	zeroTime := time.Time{}
 	entry, err := tl.UnmarshalEntry(entryBytes)
@@ -157,12 +158,12 @@ func (tl *RekorTL) VerifyLogEntry(ctx context.Context, entryBytes []byte) (time.
 	return integratedTime, nil
 }
 
-// CreateX509Cert generates a self-signed x509 cert for TL submission
+// CreateX509Cert generates a self-signed x509 cert for TL submission.
 func CreateX509Cert(subject string, signer dsse.SignerVerifier) ([]byte, error) {
 	// encode ephemeral public key
 	ecPub, err := x509.MarshalPKIXPublicKey(signer.Public())
 	if err != nil {
-		return nil, fmt.Errorf("error marshalling public key: %w", err)
+		return nil, fmt.Errorf("error marshaling public key: %w", err)
 	}
 
 	template := x509.Certificate{
@@ -180,7 +181,7 @@ func CreateX509Cert(subject string, signer dsse.SignerVerifier) ([]byte, error)
 
 	// dsse.SignerVerifier doesn't implement cypto.Signer exactly
 
-	csigner, ok := signer.(*signerverifier.ECDSA256_SignerVerifier)
+	csigner, ok := signer.(*signerverifier.ECDSA256SignerVerifier)
 	if !ok {
 		return nil, fmt.Errorf("expected signer to be of type *signerverifier.ECDSA_SignerVerifier, got %T", signer)
 	}
@@ -193,7 +194,7 @@ func CreateX509Cert(subject string, signer dsse.SignerVerifier) ([]byte, error)
 	return pem.EncodeToMemory(certBlock), nil
 }
 
-// VerifyEntryPayload checks that the TL entry payload matches envelope payload
+// VerifyEntryPayload checks that the TL entry payload matches envelope payload.
 func (tl *RekorTL) VerifyEntryPayload(entryBytes, payload, publicKey []byte) error {
 	entry, err := tl.UnmarshalEntry(entryBytes)
 	if err != nil {
@@ -228,7 +229,7 @@ func (tl *RekorTL) VerifyEntryPayload(entryBytes, payload, publicKey []byte) err
 	if err != nil {
 		return fmt.Errorf("failed to parse certificate: %w", err)
 	}
-	if string(result.RawSubjectPublicKeyInfo) != string(publicKey) {
+	if !bytes.Equal(result.RawSubjectPublicKeyInfo, publicKey) {
 		return fmt.Errorf("error payload and tl entry public key mismatch")
 	}
 	return nil
@@ -243,9 +244,9 @@ func (tl *RekorTL) UnmarshalEntry(entry []byte) (any, error) {
 	return le, nil
 }
 
-func extractHashedRekord(Body string) (*TlPayload, error) {
-	sig := new(TlPayload)
-	pe, err := models.UnmarshalProposedEntry(base64.NewDecoder(base64.StdEncoding, strings.NewReader(Body)), runtime.JSONConsumer())
+func extractHashedRekord(body string) (*TLPayload, error) {
+	sig := new(TLPayload)
+	pe, err := models.UnmarshalProposedEntry(base64.NewDecoder(base64.StdEncoding, strings.NewReader(body)), runtime.JSONConsumer())
 	if err != nil {
 		return nil, err
 	}

pkg/tlog/tl_test.go

@@ -14,7 +14,7 @@ import (
 )
 
 const (
-	// test artifacts
+	// test artifacts.
 	TestPayload   = "test"
 	TestPublicKey = "-----BEGIN PUBLIC KEY-----\nMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAED4V+REhx+aqWH7ylMMDHahNMnMLS\nOJP/9kAm9lp+3mqYTAhURra6OD5Qx8Zbd+euPyPk9y+w/gWGDB9zn/Il1A==\n-----END PUBLIC KEY-----"
 )
@@ -53,15 +53,15 @@ func TestUploadAndVerifyLogEntry(t *testing.T) {
 	assert.NoError(t, err)
 
 	var tl TL
-	if USE_MOCK_TL {
+	if UseMockTL {
 		tl = &MockTL{
-			UploadLogEntryFunc: func(ctx context.Context, subject string, payload []byte, signature []byte, signer dsse.SignerVerifier) ([]byte, error) {
+			UploadLogEntryFunc: func(_ context.Context, _ string, _ []byte, _ []byte, _ dsse.SignerVerifier) ([]byte, error) {
 				return []byte(TestEntry), nil
 			},
-			VerifyLogEntryFunc: func(ctx context.Context, entryBytes []byte) (time.Time, error) {
+			VerifyLogEntryFunc: func(_ context.Context, _ []byte) (time.Time, error) {
 				return time.Time{}, nil
 			},
-			VerifyEntryPayloadFunc: func(entryBytes, payload, publicKey []byte) error {
+			VerifyEntryPayloadFunc: func(_, _, _ []byte) error {
 				return nil
 			},
 		}

pkg/tuf/example_registry_test.go

@@ -9,7 +9,7 @@ import (
 	"github.com/theupdateframework/go-tuf/v2/metadata"
 )
 
-func ExampleNewTufClient_registry() {
+func ExampleNewClient_registry() {
 	// create a tuf client
 	home, err := os.UserHomeDir()
 	if err != nil {
@@ -21,7 +21,7 @@ func ExampleNewTufClient_registry() {
 	metadataURI := "registry-1.docker.io/docker/tuf-metadata:latest"
 	targetsURI := "registry-1.docker.io/docker/tuf-targets"
 
-	registryClient, err := tuf.NewTufClient(embed.RootStaging.Data, tufOutputPath, metadataURI, targetsURI, tuf.NewMockVersionChecker())
+	registryClient, err := tuf.NewClient(embed.RootStaging.Data, tufOutputPath, metadataURI, targetsURI, tuf.NewMockVersionChecker())
 	if err != nil {
 		panic(err)
 	}

pkg/tuf/mock.go

@@ -6,25 +6,25 @@ import (
 	"path/filepath"
 )
 
-type mockTufClient struct {
+type MockTufClient struct {
 	srcPath string
 	dstPath string
 }
 
-func NewMockTufClient(srcPath string, dstPath string) *mockTufClient {
+func NewMockTufClient(srcPath string, dstPath string) *MockTufClient {
 	if srcPath == "" {
 		panic("srcPath must be set")
 	}
 	if dstPath == "" {
 		panic("dstPath must be set")
 	}
-	return &mockTufClient{
+	return &MockTufClient{
 		srcPath: srcPath,
 		dstPath: dstPath,
 	}
 }
 
-func (dc *mockTufClient) DownloadTarget(target string, filePath string) (actualFilePath string, data []byte, err error) {
+func (dc *MockTufClient) DownloadTarget(target string, filePath string) (actualFilePath string, data []byte, err error) {
 	src, err := os.Open(filepath.Join(dc.srcPath, target))
 	if err != nil {
 		return "", nil, err
@@ -59,14 +59,14 @@ func (dc *mockTufClient) DownloadTarget(target string, filePath string) (actualF
 	return dstFilePath, b, nil
 }
 
-type mockVersionChecker struct {
+type MockVersionChecker struct {
 	err error
 }
 
-func NewMockVersionChecker() *mockVersionChecker {
-	return &mockVersionChecker{}
+func NewMockVersionChecker() *MockVersionChecker {
+	return &MockVersionChecker{}
 }
 
-func (vc *mockVersionChecker) CheckVersion(client TUFClient) error {
+func (vc *MockVersionChecker) CheckVersion(_ Downloader) error {
 	return vc.err
 }

pkg/tuf/registry.go

@@ -19,14 +19,14 @@ import (
 )
 
 const (
-	TufFileNameAnnotation = "tuf.io/filename"
+	TUFFileNameAnnotation = "tuf.io/filename"
 )
 
-type TufRole string
+type Role string
 
-var TufRoles = []TufRole{metadata.ROOT, metadata.SNAPSHOT, metadata.TARGETS, metadata.TIMESTAMP}
+var Roles = []Role{metadata.ROOT, metadata.SNAPSHOT, metadata.TARGETS, metadata.TIMESTAMP}
 
-// RegistryFetcher implements Fetcher
+// RegistryFetcher implements Fetcher.
 type RegistryFetcher struct {
 	httpUserAgent string
 	metadataRepo  string
@@ -46,13 +46,13 @@ func NewImageCache() *ImageCache {
 	}
 }
 
-// Get image from cache
+// Get image from cache.
 func (c *ImageCache) Get(imgRef string) ([]byte, bool) {
 	img, found := c.cache[imgRef]
 	return img, found
 }
 
-// Add image to cache
+// Add image to cache.
 func (c *ImageCache) Put(imgRef string, img []byte) {
 	c.cache[imgRef] = img
 }
@@ -113,7 +113,7 @@ func (d *RegistryFetcher) DownloadFile(urlPath string, maxLength int64, timeout
 	}
 }
 
-// getManifest returns the manifest for an image or index
+// getManifest returns the manifest for an image or index.
 func (d *RegistryFetcher) getManifest(ref string) ([]byte, error) {
 	// Pull image manifest
 	var err error
@@ -135,7 +135,7 @@ func (d *RegistryFetcher) getManifest(ref string) ([]byte, error) {
 	return mf, nil
 }
 
-// pullFileLayer pulls a layer for an image or index and returns its data
+// pullFileLayer pulls a layer for an image or index and returns its data.
 func (d *RegistryFetcher) pullFileLayer(ref string, maxLength int64) ([]byte, error) {
 	var data []byte
 	var found bool
@@ -159,7 +159,7 @@ func (d *RegistryFetcher) pullFileLayer(ref string, maxLength int64) ([]byte, er
 	return data, nil
 }
 
-// getDataFromLayer returns the data from a layer in an image
+// getDataFromLayer returns the data from a layer in an image.
 func getDataFromLayer(fileLayer v1.Layer, maxLength int64) ([]byte, error) {
 	length, err := fileLayer.Size()
 	if err != nil {
@@ -185,7 +185,7 @@ func getDataFromLayer(fileLayer v1.Layer, maxLength int64) ([]byte, error) {
 	return data, nil
 }
 
-// parseImgRef maintains the Fetcher interface by parsing a URL path to an image reference and file name
+// parseImgRef maintains the Fetcher interface by parsing a URL path to an image reference and file name.
 func (d *RegistryFetcher) parseImgRef(urlPath string) (imgRef, fileName string, err error) {
 	// Check if repo is target or metadata
 	if strings.Contains(urlPath, d.targetsRepo) {
@@ -208,12 +208,11 @@ func (d *RegistryFetcher) parseImgRef(urlPath string) (imgRef, fileName string,
 			return fmt.Sprintf("%s:%s", d.metadataRepo, role), fileName, nil
 		}
 		return fmt.Sprintf("%s:%s", d.metadataRepo, d.metadataTag), fileName, nil
-	} else {
-		return "", "", fmt.Errorf("urlPath: %s must be in metadata or targets repo", urlPath)
 	}
+	return "", "", fmt.Errorf("urlPath: %s must be in metadata or targets repo", urlPath)
 }
 
-// findFileInManifest searches the image or index manifest for a file with the given name and returns its digest
+// findFileInManifest searches the image or index manifest for a file with the given name and returns its digest.
 func (d *RegistryFetcher) findFileInManifest(mf []byte, name string) (*v1.Hash, error) {
 	var index bool
 
@@ -226,20 +225,21 @@ func (d *RegistryFetcher) findFileInManifest(mf []byte, name string) (*v1.Hash,
 
 	// determine image or index manifest
 	var layers []Layer
-	if l.MediaType == string(types.OCIImageIndex) {
+	switch l.MediaType {
+	case string(types.OCIImageIndex):
 		layers = l.Manifests
 		index = true
-	} else if l.MediaType == string(types.OCIManifestSchema1) {
+	case string(types.OCIManifestSchema1):
 		layers = l.Layers
 		index = false
-	} else {
+	default:
 		return nil, fmt.Errorf("invalid manifest media type: %s", l.MediaType)
 	}
 
 	// find annotation with file name
 	var digest string
 	for _, layer := range layers {
-		if layer.Annotations[TufFileNameAnnotation] == name {
+		if layer.Annotations[TUFFileNameAnnotation] == name {
 			digest = layer.Digest
 			break
 		}
@@ -267,7 +267,7 @@ func (d *RegistryFetcher) findFileInManifest(mf []byte, name string) (*v1.Hash,
 	return hash, nil
 }
 
-// transportWithTimeout returns a http.RoundTripper with a specified timeout
+// transportWithTimeout returns a http.RoundTripper with a specified timeout.
 func transportWithTimeout(timeout time.Duration) http.RoundTripper {
 	// transport is based on go-containerregistry remote.DefaultTransport
 	// with modifications to include a specified timeout
@@ -286,9 +286,9 @@ func transportWithTimeout(timeout time.Duration) http.RoundTripper {
 	}
 }
 
-// isDelegatedRole returns true if the role is a delegated role
+// isDelegatedRole returns true if the role is a delegated role.
 func isDelegatedRole(role string) bool {
-	for _, r := range TufRoles {
+	for _, r := range Roles {
 		if role == string(r) {
 			return false // role is not a delegated role
 		}
@@ -296,7 +296,7 @@ func isDelegatedRole(role string) bool {
 	return true // role is a delegated role
 }
 
-// roleFromConsistentName returns the role name from a consistent snapshot file name
+// roleFromConsistentName returns the role name from a consistent snapshot file name.
 func roleFromConsistentName(filename string) string {
 	name := strings.TrimSuffix(filename, ".json")
 	role := strings.Split(name, ".")

pkg/tuf/registry_test.go

@@ -30,6 +30,8 @@ import (
 
 const (
 	tufTargetMediaType = "application/vnd.tuf.target"
+	testRole           = "test-role"
+	tufMetadataRepo    = "tuf-metadata"
 )
 
 func TestRegistryFetcher(t *testing.T) {
@@ -40,13 +42,13 @@ func TestRegistryFetcher(t *testing.T) {
 			t.Fatalf("failed to terminate container: %s", err) // nolint:gocritic
 		}
 	}()
-	LoadRegistryTestData(t, regAddr, OciTufTestDataPath)
+	LoadRegistryTestData(t, regAddr, OCITUFTestDataPath)
 
 	metadataRepo := regAddr.Host + "/tuf-metadata"
-	metadataImgTag := "latest"
+	metadataImgTag := LatestTag
 	targetsRepo := regAddr.Host + "/tuf-targets"
 	targetFile := "test.txt"
-	delegatedRole := "test-role"
+	delegatedRole := testRole
 	dir := CreateTempDir(t, "", "tuf_temp")
 	delegatedDir := CreateTempDir(t, dir, delegatedRole)
 	delegatedTargetFile := fmt.Sprintf("%s/%s", delegatedRole, targetFile)
@@ -126,11 +128,11 @@ func TestFindFileInManifest(t *testing.T) {
 	img = mutate.ConfigMediaType(img, types.OCIConfigJSON)
 	// add test layer
 	name := strings.Join([]string{hash.Hex, file}, ".")
-	ann := map[string]string{TufFileNameAnnotation: name}
+	ann := map[string]string{TUFFileNameAnnotation: name}
 	layer := mutate.Addendum{Layer: static.NewLayer(data, tufTargetMediaType), Annotations: ann}
 	img, err := mutate.Append(img, layer)
 	assert.NoError(t, err)
-	image_manifest, err := img.RawManifest()
+	imageManifest, err := img.RawManifest()
 	assert.NoError(t, err)
 
 	// make test index manifest
@@ -141,11 +143,11 @@ func TestFindFileInManifest(t *testing.T) {
 		Add: img,
 		Descriptor: v1.Descriptor{
 			Annotations: map[string]string{
-				TufFileNameAnnotation: name,
+				TUFFileNameAnnotation: name,
 			},
 		},
 	})
-	index_manifest, err := idx.RawManifest()
+	indexManifest, err := idx.RawManifest()
 	assert.NoError(t, err)
 	// cache image layer
 	targetsRepo := "test/tuf-targets"
@@ -155,7 +157,7 @@ func TestFindFileInManifest(t *testing.T) {
 	}
 	imgHash, err := img.Digest()
 	assert.NoError(t, err)
-	d.cache.Put(fmt.Sprintf("%s@%s", targetsRepo, imgHash.String()), image_manifest)
+	d.cache.Put(fmt.Sprintf("%s@%s", targetsRepo, imgHash.String()), imageManifest)
 
 	testCases := []struct {
 		name     string
@@ -163,9 +165,9 @@ func TestFindFileInManifest(t *testing.T) {
 		file     string
 		expected string
 	}{
-		{"consistent filename image", image_manifest, fmt.Sprintf("%s.%s", hash.Hex, file), hash.Hex},
-		{"filename image", image_manifest, file, ""},
-		{"consistent filename index", index_manifest, fmt.Sprintf("%s.%s", hash.Hex, file), hash.Hex},
+		{"consistent filename image", imageManifest, fmt.Sprintf("%s.%s", hash.Hex, file), hash.Hex},
+		{"filename image", imageManifest, file, ""},
+		{"consistent filename index", indexManifest, fmt.Sprintf("%s.%s", hash.Hex, file), hash.Hex},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
@@ -182,9 +184,9 @@ func TestFindFileInManifest(t *testing.T) {
 
 func TestParseImgRef(t *testing.T) {
 	metadataRepo := "test/tuf-metadata"
-	metadataTag := "latest"
+	metadataTag := LatestTag
 	targetsRepo := "test/tuf-targets"
-	delegatedRole := "test-role"
+	delegatedRole := testRole
 	testCases := []struct {
 		name         string
 		ref          string
@@ -200,7 +202,7 @@ func TestParseImgRef(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			d := &RegistryFetcher{
 				metadataRepo: metadataRepo,
-				metadataTag:  "latest",
+				metadataTag:  LatestTag,
 				targetsRepo:  targetsRepo,
 			}
 			imgRef, file, err := d.parseImgRef(tc.ref)
@@ -246,7 +248,7 @@ func TestPullFileLayer(t *testing.T) {
 	}()
 
 	// make test layer
-	repo := "tuf-metadata"
+	repo := tufMetadataRepo
 	data := []byte("test")
 	testLayer := static.NewLayer(data, tufTargetMediaType)
 	hash, err := testLayer.Digest()
@@ -303,7 +305,7 @@ func TestGetManifest(t *testing.T) {
 	}()
 
 	// make test manifest
-	repo := "tuf-metadata"
+	repo := tufMetadataRepo
 	img := empty.Image
 	img = mutate.MediaType(img, types.OCIManifestSchema1)
 	img = mutate.ConfigMediaType(img, types.OCIConfigJSON)
@@ -339,7 +341,7 @@ func TestGetManifest(t *testing.T) {
 	}
 }
 
-// RunTestRegistry starts a registry testcontainer for TUF on OCI testdata
+// RunTestRegistry starts a registry testcontainer for TUF on OCI testdata.
 func RunTestRegistry(t *testing.T) (*registry.RegistryContainer, *url.URL) {
 	registryContainer, err := registry.Run(context.Background(), "registry:2.8.3")
 	if err != nil {
@@ -359,22 +361,21 @@ func RunTestRegistry(t *testing.T) (*registry.RegistryContainer, *url.URL) {
 	return registryContainer, addr
 }
 
-// LoadRegistryTestData pushes TUF metadata and targets to an OCI registry
+// LoadRegistryTestData pushes TUF metadata and targets to an OCI registry.
 func LoadRegistryTestData(t *testing.T, registry *url.URL, path string) {
 	// push tuf metadata and targets to local registry
-	METADATA_REPO := "tuf-metadata"
-	METADATA_TAG := "latest"
-	TARGETS_REPO := "tuf-targets"
-	DELEGATED_ROLE := "test-role"
+	MetadataRepo := tufMetadataRepo
+	TargetsRepo := "tuf-targets"
+	DelegatedRole := testRole
 
 	// push top-level metadata -> metadata:latest
-	err := LoadMetadata(filepath.Join(path, "metadata"), registry.Host, METADATA_REPO, METADATA_TAG)
+	err := LoadMetadata(filepath.Join(path, "metadata"), registry.Host, MetadataRepo, LatestTag)
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	// push delegated metadata -> metadata:<DELEGATED_ROLE>
-	err = LoadMetadata(filepath.Join(path, "metadata", DELEGATED_ROLE), registry.Host, METADATA_REPO, DELEGATED_ROLE)
+	err = LoadMetadata(filepath.Join(path, "metadata", DelegatedRole), registry.Host, MetadataRepo, DelegatedRole)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -392,7 +393,7 @@ func LoadRegistryTestData(t *testing.T, registry *url.URL, path string) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		ref, err := name.ParseReference(fmt.Sprintf("%s/%s:%s", registry.Host, TARGETS_REPO, dir.Name()))
+		ref, err := name.ParseReference(fmt.Sprintf("%s/%s:%s", registry.Host, TargetsRepo, dir.Name()))
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -400,7 +401,8 @@ func LoadRegistryTestData(t *testing.T, registry *url.URL, path string) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if len(mf.Manifests) == 1 {
+		switch len(mf.Manifests) {
+		case 1:
 			// top-level target
 			img, err := tIdx.Image(mf.Manifests[0].Digest)
 			if err != nil {
@@ -410,19 +412,19 @@ func LoadRegistryTestData(t *testing.T, registry *url.URL, path string) {
 			if err != nil {
 				t.Fatal(err)
 			}
-		} else if len(mf.Manifests) > 1 {
+		case 2:
 			// delegated target
 			err = remote.WriteIndex(ref, tIdx, oci.MultiKeychainOption())
 			if err != nil {
 				t.Fatal(err)
 			}
-		} else {
+		default:
 			t.Fatal("no manifests found")
 		}
 	}
 }
 
-// LoadMetadata loads TUF metadata from a local path and pushes to a registry
+// LoadMetadata loads TUF metadata from a local path and pushes to a registry.
 func LoadMetadata(path, host, repo, tag string) error {
 	mIdx, err := layout.ImageIndexFromPath(path)
 	if err != nil {

pkg/tuf/tuf.go

@@ -20,36 +20,37 @@ import (
 	"github.com/theupdateframework/go-tuf/v2/metadata/updater"
 )
 
-type TufSource string
+type Source string
 
 const (
-	HttpSource TufSource = "http"
-	OciSource  TufSource = "oci"
+	HTTPSource Source = "http"
+	OCISource  Source = "oci"
+	LatestTag  string = "latest"
 )
 
 var (
-	DockerTufRootProd    = embed.RootProd
-	DockerTufRootStaging = embed.RootStaging
-	DockerTufRootDev     = embed.RootDev
-	DockerTufRootDefault = embed.RootDefault
+	DockerTUFRootProd    = embed.RootProd
+	DockerTUFRootStaging = embed.RootStaging
+	DockerTUFRootDev     = embed.RootDev
+	DockerTUFRootDefault = embed.RootDefault
 )
 
-type TUFClient interface {
+type Downloader interface {
 	DownloadTarget(target, filePath string) (actualFilePath string, data []byte, err error)
 }
 
-type TufClient struct {
+type Client struct {
 	updater *updater.Updater
 	cfg     *config.UpdaterConfig
 }
 
-// NewTufClient creates a new TUF client
-func NewTufClient(initialRoot []byte, tufPath, metadataSource, targetsSource string, versionChecker VersionChecker) (*TufClient, error) {
-	var tufSource TufSource
+// NewClient creates a new TUF client.
+func NewClient(initialRoot []byte, tufPath, metadataSource, targetsSource string, versionChecker VersionChecker) (*Client, error) {
+	var tufSource Source
 	if strings.HasPrefix(metadataSource, "https://") || strings.HasPrefix(metadataSource, "http://") {
-		tufSource = HttpSource
+		tufSource = HTTPSource
 	} else {
-		tufSource = OciSource
+		tufSource = OCISource
 	}
 
 	tufRootDigest := util.SHA256Hex(initialRoot)
@@ -84,11 +85,11 @@ func NewTufClient(initialRoot []byte, tufPath, metadataSource, targetsSource str
 	cfg.LocalTargetsDir = filepath.Join(metadataPath, "download")
 	cfg.RemoteTargetsURL = targetsSource
 
-	if tufSource == OciSource {
+	if tufSource == OCISource {
 		metadataRepo, metadataTag, found := strings.Cut(metadataSource, ":")
 		if !found {
 			fmt.Printf("metadata tag not found in URL, using latest\n")
-			metadataTag = "latest"
+			metadataTag = LatestTag
 		}
 		cfg.Fetcher = NewRegistryFetcher(metadataRepo, metadataTag, targetsSource)
 	}
@@ -105,7 +106,7 @@ func NewTufClient(initialRoot []byte, tufPath, metadataSource, targetsSource str
 		return nil, fmt.Errorf("failed to refresh trusted metadata: %w", err)
 	}
 
-	client := &TufClient{
+	client := &Client{
 		updater: up,
 		cfg:     cfg,
 	}
@@ -121,7 +122,7 @@ func NewTufClient(initialRoot []byte, tufPath, metadataSource, targetsSource str
 // DownloadTarget downloads the target file using Updater. The Updater gets the target
 // information, verifies if the target is already cached, and if it is not cached,
 // downloads the target file.
-func (t *TufClient) DownloadTarget(target string, filePath string) (actualFilePath string, data []byte, err error) {
+func (t *Client) DownloadTarget(target string, filePath string) (actualFilePath string, data []byte, err error) {
 	// search if the desired target is available
 	targetInfo, err := t.updater.GetTargetInfo(target)
 	if err != nil {
@@ -154,15 +155,15 @@ func (t *TufClient) DownloadTarget(target string, filePath string) (actualFilePa
 	return actualFilePath, data, err
 }
 
-func (t *TufClient) GetMetadata() trustedmetadata.TrustedMetadata {
+func (t *Client) GetMetadata() trustedmetadata.TrustedMetadata {
 	return t.updater.GetTrustedMetadataSet()
 }
 
-func (t *TufClient) MaxRootLength() int64 {
+func (t *Client) MaxRootLength() int64 {
 	return t.cfg.RootMaxLength
 }
 
-func (t *TufClient) GetPriorRoots(metadataURL string) (map[string][]byte, error) {
+func (t *Client) GetPriorRoots(metadataURL string) (map[string][]byte, error) {
 	rootMetadata := map[string][]byte{}
 	trustedMetadata := t.GetMetadata()
 	client := fetcher.DefaultFetcher{}
@@ -176,12 +177,12 @@ func (t *TufClient) GetPriorRoots(metadataURL string) (map[string][]byte, error)
 	return rootMetadata, nil
 }
 
-func (t *TufClient) SetRemoteTargetsURL(url string) {
+func (t *Client) SetRemoteTargetsURL(url string) {
 	t.cfg.RemoteTargetsURL = url
 }
 
-// Derived from updater.loadTargets() in theupdateframework/go-tuf
-func (t *TufClient) LoadDelegatedTargets(roleName, parentName string) (*metadata.Metadata[metadata.TargetsType], error) {
+// Derived from updater.loadTargets() in theupdateframework/go-tuf.
+func (t *Client) LoadDelegatedTargets(roleName, parentName string) (*metadata.Metadata[metadata.TargetsType], error) {
 	// extract the targets meta from the trusted snapshot metadata
 	meta := t.updater.GetTrustedMetadataSet()
 	metaInfo := meta.Snapshot.Signed.Meta[fmt.Sprintf("%s.json", roleName)]
@@ -208,8 +209,8 @@ func (t *TufClient) LoadDelegatedTargets(roleName, parentName string) (*metadata
 	return delegatedTargets, nil
 }
 
-// downloadMetadata download a metadata file and return it as bytes
-func (t *TufClient) downloadMetadata(roleName string, length int64, version string) ([]byte, error) {
+// downloadMetadata download a metadata file and return it as bytes.
+func (t *Client) downloadMetadata(roleName string, length int64, version string) ([]byte, error) {
 	urlPath := ensureTrailingSlash(t.cfg.RemoteMetadataURL)
 	// build urlPath
 	if version == "" {
@@ -220,7 +221,7 @@ func (t *TufClient) downloadMetadata(roleName string, length int64, version stri
 	return t.cfg.Fetcher.DownloadFile(urlPath, length, time.Second*15)
 }
 
-// ensureTrailingSlash ensures url ends with a slash
+// ensureTrailingSlash ensures url ends with a slash.
 func ensureTrailingSlash(url string) string {
 	if updater.IsWindowsPath(url) {
 		slash := string(filepath.Separator)
@@ -235,7 +236,7 @@ func ensureTrailingSlash(url string) string {
 	return url + "/"
 }
 
-// GetEmbeddedTufRoot returns the embedded TUF root based on the given root name
-func GetEmbeddedTufRoot(root string) (*embed.EmbeddedRoot, error) {
+// GetEmbeddedRoot returns the embedded TUF root based on the given root name.
+func GetEmbeddedRoot(root string) (*embed.EmbeddedRoot, error) {
 	return embed.GetRootFromName(root)
 }

pkg/tuf/tuf_test.go

@@ -15,8 +15,8 @@ import (
 )
 
 var (
-	HttpTufTestDataPath = filepath.Join("..", "..", "test", "testdata", "tuf", "test-repo")
-	OciTufTestDataPath  = filepath.Join("..", "..", "test", "testdata", "tuf", "test-repo-oci")
+	HTTPTUFTestDataPath = filepath.Join("..", "..", "test", "testdata", "tuf", "test-repo")
+	OCITUFTestDataPath  = filepath.Join("..", "..", "test", "testdata", "tuf", "test-repo-oci")
 )
 
 func CreateTempDir(t *testing.T, dir, pattern string) string {
@@ -35,12 +35,12 @@ func CreateTempDir(t *testing.T, dir, pattern string) string {
 	return tempDir
 }
 
-// NewTufClient creates a new TUF client
+// NewTufClient creates a new TUF client.
 func TestRootInit(t *testing.T) {
 	tufPath := CreateTempDir(t, "", "tuf_temp")
 
 	// Start a test HTTP server to serve data from /test/testdata/tuf/test-repo/ paths
-	server := httptest.NewServer(http.FileServer(http.Dir(HttpTufTestDataPath)))
+	server := httptest.NewServer(http.FileServer(http.Dir(HTTPTUFTestDataPath)))
 	defer server.Close()
 
 	// run local registry
@@ -50,10 +50,10 @@ func TestRootInit(t *testing.T) {
 			t.Fatalf("failed to terminate container: %s", err) // nolint:gocritic
 		}
 	}()
-	LoadRegistryTestData(t, regAddr, OciTufTestDataPath)
+	LoadRegistryTestData(t, regAddr, OCITUFTestDataPath)
 
-	alwaysGoodVersionChecker := &mockVersionChecker{err: nil}
-	alwaysBadVersionChecker := &mockVersionChecker{err: assert.AnError}
+	alwaysGoodVersionChecker := &MockVersionChecker{err: nil}
+	alwaysBadVersionChecker := &MockVersionChecker{err: assert.AnError}
 
 	testCases := []struct {
 		name           string
@@ -65,17 +65,17 @@ func TestRootInit(t *testing.T) {
 	}
 
 	for _, tc := range testCases {
-		_, err := NewTufClient(embed.RootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker)
+		_, err := NewClient(embed.RootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker)
 		assert.NoErrorf(t, err, "Failed to create TUF client: %v", err)
 
 		// recreation should work with same root
-		_, err = NewTufClient(embed.RootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker)
+		_, err = NewClient(embed.RootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker)
 		assert.NoErrorf(t, err, "Failed to recreate TUF client: %v", err)
 
-		_, err = NewTufClient([]byte("broken"), tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker)
+		_, err = NewClient([]byte("broken"), tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker)
 		assert.Errorf(t, err, "Expected error recreating TUF client with broken root: %v", err)
 
-		_, err = NewTufClient(embed.RootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysBadVersionChecker)
+		_, err = NewClient(embed.RootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysBadVersionChecker)
 		assert.Errorf(t, err, "Expected error creating TUF client with bad attest version: %v", err)
 	}
 }
@@ -83,11 +83,11 @@ func TestRootInit(t *testing.T) {
 func TestDownloadTarget(t *testing.T) {
 	tufPath := CreateTempDir(t, "", "tuf_temp")
 	targetFile := "test.txt"
-	delegatedRole := "test-role"
+	delegatedRole := testRole
 	delegatedTargetFile := fmt.Sprintf("%s/%s", delegatedRole, targetFile)
 
 	// Start a test HTTP server to serve data from /test/testdata/tuf/test-repo/ paths
-	server := httptest.NewServer(http.FileServer(http.Dir(HttpTufTestDataPath)))
+	server := httptest.NewServer(http.FileServer(http.Dir(HTTPTUFTestDataPath)))
 	defer server.Close()
 
 	// run local registry
@@ -97,9 +97,9 @@ func TestDownloadTarget(t *testing.T) {
 			t.Fatalf("failed to terminate container: %s", err) // nolint:gocritic
 		}
 	}()
-	LoadRegistryTestData(t, regAddr, OciTufTestDataPath)
+	LoadRegistryTestData(t, regAddr, OCITUFTestDataPath)
 
-	alwaysGoodVersionChecker := &mockVersionChecker{err: nil}
+	alwaysGoodVersionChecker := &MockVersionChecker{err: nil}
 
 	testCases := []struct {
 		name           string
@@ -111,7 +111,7 @@ func TestDownloadTarget(t *testing.T) {
 	}
 
 	for _, tc := range testCases {
-		tufClient, err := NewTufClient(embed.RootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker)
+		tufClient, err := NewClient(embed.RootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker)
 		assert.NoErrorf(t, err, "Failed to create TUF client: %v", err)
 
 		// get trusted tuf metadata
@@ -135,22 +135,22 @@ func TestDownloadTarget(t *testing.T) {
 }
 
 func TestGetEmbeddedTufRootBytes(t *testing.T) {
-	dev, err := GetEmbeddedTufRoot("dev")
+	dev, err := GetEmbeddedRoot("dev")
 	assert.NoError(t, err)
 
-	staging, err := GetEmbeddedTufRoot("staging")
+	staging, err := GetEmbeddedRoot("staging")
 	assert.NoError(t, err)
 	assert.NotEqual(t, dev.Data, staging.Data)
 
-	prod, err := GetEmbeddedTufRoot("prod")
+	prod, err := GetEmbeddedRoot("prod")
 	assert.NoError(t, err)
 	assert.NotEqual(t, dev.Data, prod.Data)
 	assert.NotEqual(t, staging.Data, prod.Data)
 
-	def, err := GetEmbeddedTufRoot("")
+	def, err := GetEmbeddedRoot("")
 	assert.NoError(t, err)
 	assert.Equal(t, def.Data, prod.Data)
 
-	_, err = GetEmbeddedTufRoot("invalid")
+	_, err = GetEmbeddedRoot("invalid")
 	assert.Error(t, err)
 }

pkg/tuf/version.go

@@ -12,7 +12,7 @@ const ThisModulePath = "github.com/docker/attest"
 
 type VersionChecker interface {
 	// CheckVersion checks if the current version of this library meets the constraints from the TUF repo
-	CheckVersion(tufClient TUFClient) error
+	CheckVersion(tufClient Downloader) error
 }
 
 type InvalidVersionError struct {
@@ -32,13 +32,13 @@ func (e *InvalidVersionError) Error() string {
 	return fmt.Sprintf("%s version %s does not satisfy constraints %s: %s", ThisModulePath, e.AttestVersion, e.VersionConstraint, errsStr.String())
 }
 
-func NewVersionChecker() *versionChecker {
-	return &versionChecker{}
+func NewDefaultVersionChecker() *DefaultVersionChecker {
+	return &DefaultVersionChecker{}
 }
 
-type versionChecker struct{}
+type DefaultVersionChecker struct{}
 
-func (vc *versionChecker) CheckVersion(client TUFClient) error {
+func (vc *DefaultVersionChecker) CheckVersion(client Downloader) error {
 	var attestMod *debug.Module
 	bi, ok := debug.ReadBuildInfo()
 	if !ok {