try out metadata abstraction instead

Signed-off-by: Meredith Lancaster <malancas@github.com>

pkg/cmd/attestation/download/download.go

@@ -136,13 +136,11 @@ func runDownload(opts *Options) error {
 		return fmt.Errorf("failed to fetch attestations: %w", err)
 	}
 
-	filePath := createJSONLinesFilePath(artifact.DigestWithAlg(), opts.OutputPath)
-	fmt.Fprintf(opts.Logger.IO.Out, "Writing attestations to file %s.\nAny previous content will be overwritten\n\n", filePath)
-
-	metadataFilePath, err := createMetadataFile(attestations, filePath)
+	metadataFilePath, err := opts.Store.createMetadataFile(artifact.DigestWithAlg(), attestations)
 	if err != nil {
 		return fmt.Errorf("failed to write attestation: %w", err)
 	}
+	fmt.Fprintf(opts.Logger.IO.Out, "Wrote attestations to file %s.\nAny previous content has been overwritten\n\n", metadataFilePath)
 
 	fmt.Fprint(opts.Logger.IO.Out,
 		opts.Logger.ColorScheme.Greenf(

pkg/cmd/attestation/download/download_test.go

@@ -33,7 +33,10 @@ func TestNewDownloadCmd(t *testing.T) {
 			return client, nil
 		},
 	}
-	tempDir := t.TempDir()
+
+	store := &MetadataStore{
+		outputPath: t.TempDir(),
+	}
 
 	testcases := []struct {
 		name     string
@@ -50,7 +53,7 @@ func TestNewDownloadCmd(t *testing.T) {
 				OCIClient:       oci.MockClient{},
 				DigestAlgorithm: "sha384",
 				Owner:           "sigstore",
-				OutputPath:      tempDir,
+				Store:           store,
 				Limit:           30,
 			},
 			wantsErr: true,
@@ -64,7 +67,7 @@ func TestNewDownloadCmd(t *testing.T) {
 				OCIClient:       oci.MockClient{},
 				DigestAlgorithm: "sha256",
 				Owner:           "sigstore",
-				OutputPath:      tempDir,
+				Store:           store,
 				Limit:           30,
 			},
 			wantsErr: false,
@@ -78,7 +81,7 @@ func TestNewDownloadCmd(t *testing.T) {
 				OCIClient:       oci.MockClient{},
 				DigestAlgorithm: "sha256",
 				Owner:           "sigstore",
-				OutputPath:      tempDir,
+				Store:           store,
 				Limit:           30,
 			},
 			wantsErr: true,
@@ -92,7 +95,7 @@ func TestNewDownloadCmd(t *testing.T) {
 				OCIClient:       oci.MockClient{},
 				DigestAlgorithm: "sha256",
 				Owner:           "sigstore",
-				OutputPath:      tempDir,
+				Store:           store,
 				Repo:            "sigstore/sigstore-js",
 				Limit:           30,
 			},
@@ -107,7 +110,7 @@ func TestNewDownloadCmd(t *testing.T) {
 				OCIClient:       oci.MockClient{},
 				DigestAlgorithm: "sha256",
 				Owner:           "sigstore",
-				OutputPath:      tempDir,
+				Store:           store,
 				Limit:           30,
 			},
 			wantsErr: false,
@@ -121,7 +124,7 @@ func TestNewDownloadCmd(t *testing.T) {
 				OCIClient:       oci.MockClient{},
 				DigestAlgorithm: "sha256",
 				Owner:           "sigstore",
-				OutputPath:      tempDir,
+				Store:           store,
 				Limit:           101,
 			},
 			wantsErr: false,
@@ -135,7 +138,7 @@ func TestNewDownloadCmd(t *testing.T) {
 				OCIClient:       oci.MockClient{},
 				DigestAlgorithm: "sha256",
 				Owner:           "sigstore",
-				OutputPath:      tempDir,
+				Store:           store,
 				Limit:           0,
 			},
 			wantsErr: true,
@@ -173,6 +176,9 @@ func TestNewDownloadCmd(t *testing.T) {
 
 func TestRunDownload(t *testing.T) {
 	tempDir := t.TempDir()
+	store := &MetadataStore{
+		outputPath: tempDir,
+	}
 
 	baseOpts := Options{
 		ArtifactPath:    "../test/data/sigstore-js-2.1.0.tgz",
@@ -180,7 +186,7 @@ func TestRunDownload(t *testing.T) {
 		OCIClient:       oci.MockClient{},
 		DigestAlgorithm: "sha512",
 		Owner:           "sigstore",
-		OutputPath:      tempDir,
+		Store:           store,
 		Limit:           30,
 		Logger:          logging.NewTestLogger(),
 	}

pkg/cmd/attestation/download/metadata.go

@@ -0,0 +1,54 @@
+package download
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/cli/cli/v2/pkg/cmd/attestation/api"
+)
+
+type MetadataStore struct {
+	outputPath string
+}
+
+func (s *MetadataStore) createJSONLinesFilePath(artifact string) string {
+	path := fmt.Sprintf("%s.jsonl", artifact)
+	if s.outputPath != "" {
+		return fmt.Sprintf("%s/%s", s.outputPath, path)
+	}
+	return path
+}
+
+func (s *MetadataStore) createMetadataFile(artifactDigest string, attestationsResp []*api.Attestation) (string, error) {
+	metadataFilePath := s.createJSONLinesFilePath(artifactDigest)
+
+	f, err := os.Create(metadataFilePath)
+	if err != nil {
+		return "", fmt.Errorf("failed to create trusted metadata file: %w", err)
+	}
+
+	for _, resp := range attestationsResp {
+		bundle := resp.Bundle
+		attBytes, err := json.Marshal(bundle)
+		if err != nil {
+			return "", fmt.Errorf("failed to marshall attestation to JSON: %w", err)
+		}
+
+		withNewline := fmt.Sprintf("%s\n", attBytes)
+		_, err = f.Write([]byte(withNewline))
+		if err != nil {
+			if err = f.Close(); err != nil {
+				return "", fmt.Errorf("failed to close file while handling write error: %w", err)
+			}
+
+			return "", fmt.Errorf("failed to write trusted metadata: %w", err)
+		}
+	}
+
+	if err = f.Close(); err != nil {
+		return "", fmt.Errorf("failed to close file after writing metadata: %w", err)
+	}
+
+	return metadataFilePath, nil
+}

pkg/cmd/attestation/download/options.go

@@ -19,8 +19,8 @@ type Options struct {
 	DigestAlgorithm string
 	Logger          *logging.Logger
 	Limit           int
+	Store           *MetadataStore
 	OCIClient       oci.Client
-	OutputPath      string
 	Owner           string
 	Repo            string
 	Verbose         bool