Use policy files from mapping.yaml (#30)

* Use policy files from mapping.yaml

* Rename location to root in mapping.yaml

* Remove location/root

pkg/policy/policy.go

@@ -20,10 +20,6 @@ const (
 	PolicyMappingFileName = "mapping.yaml"
 )
 
-var (
-	PolicyFileNames = []string{"data.yaml", "policy.rego"}
-)
-
 type PolicyMappings struct {
 	Version  string          `json:"version"`
 	Kind     string          `json:"kind"`
@@ -32,10 +28,14 @@ type PolicyMappings struct {
 }
 
 type PolicyMapping struct {
-	Name        string       `json:"namespace"`
-	Location    string       `json:"location"`
-	Description string       `json:"description"`
-	Origin      PolicyOrigin `json:"origin"`
+	Name        string              `json:"namespace"`
+	Description string              `json:"description"`
+	Origin      PolicyOrigin        `json:"origin"`
+	Files       []PolicyMappingFile `json:"files"`
+}
+
+type PolicyMappingFile struct {
+	Path string `json:"path"`
 }
 
 type PolicyMirror struct {
@@ -75,9 +75,10 @@ func resolveLocalPolicy(opts *PolicyOptions, mapping *PolicyMapping) ([]*PolicyF
 	if opts.LocalPolicyDir == "" {
 		return nil, fmt.Errorf("local policy dir not set")
 	}
-	files := make([]*PolicyFile, 0, len(PolicyFileNames))
-	for _, filename := range PolicyFileNames {
-		filePath := path.Join(opts.LocalPolicyDir, mapping.Location, filename)
+	files := make([]*PolicyFile, 0, len(mapping.Files))
+	for _, f := range mapping.Files {
+		filename := f.Path
+		filePath := path.Join(opts.LocalPolicyDir, filename)
 		fileContents, err := os.ReadFile(filePath)
 		if err != nil {
 			return nil, fmt.Errorf("failed to read policy file %s: %w", filename, err)
@@ -108,10 +109,10 @@ func loadLocalMappings(opts *PolicyOptions) (*PolicyMappings, error) {
 }
 
 func resolveTufPolicy(opts *PolicyOptions, mapping *PolicyMapping) ([]*PolicyFile, error) {
-	files := make([]*PolicyFile, 0, len(PolicyFileNames))
-	for _, filename := range PolicyFileNames {
-		filePath := path.Join(mapping.Location, filename)
-		_, fileContents, err := opts.TufClient.DownloadTarget(filePath, filepath.Join(opts.LocalTargetsDir, filePath))
+	files := make([]*PolicyFile, 0, len(mapping.Files))
+	for _, f := range mapping.Files {
+		filename := f.Path
+		_, 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)
 		}

pkg/policy/testdata/mock-tuf-allow/doi/data.yaml

@@ -1 +0,0 @@
-config:

pkg/policy/testdata/mock-tuf-allow/mapping.yaml

@@ -7,4 +7,5 @@ policies:
       prefix: library/
     name: docker-official-images
     description: Docker Official Images
-    location: doi
+    files:
+      - path: doi/policy.rego

pkg/policy/testdata/mock-tuf-deny/doi/data.yaml

@@ -1 +0,0 @@
-config:

pkg/policy/testdata/mock-tuf-deny/mapping.yaml

@@ -7,4 +7,5 @@ policies:
       prefix: library/
     name: docker-official-images
     description: Docker Official Images
-    location: doi
+    files:
+      - path: doi/policy.rego

pkg/policy/testdata/mock-tuf-verify-sig/doi/data.yaml

@@ -1 +0,0 @@
-config:

pkg/policy/testdata/mock-tuf-verify-sig/mapping.yaml

@@ -7,4 +7,5 @@ policies:
       prefix: library/
     name: docker-official-images
     description: Docker Official Images
-    location: doi
+    files:
+      - path: doi/policy.rego

pkg/policy/testdata/mock-tuf-wrong-key/doi/data.yaml

@@ -1 +0,0 @@
-config:

pkg/policy/testdata/mock-tuf-wrong-key/mapping.yaml

@@ -7,4 +7,5 @@ policies:
       prefix: library/
     name: docker-official-images
     description: Docker Official Images
-    location: doi
+    files:
+      - path: doi/policy.rego

test/testdata/local-policy/mapping.yaml

@@ -7,7 +7,9 @@ policies:
       prefix: library/
     name: test-images
     description: Local test images
-    location: doi
+    files:
+      - path: doi/data.yaml
+      - path: doi/policy.rego
 
 mirrors:
   - name: test-images