Simplify the interface of parseSingleAuthHeader

Don't create a single-element map only for the only caller
to laboriously extract an element of that map; just return
a single entry.

Should not change behavior.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

pkg/auth/auth.go

@@ -121,17 +121,11 @@ func getAuthCredentials(r *http.Request) (*types.DockerAuthConfig, string, error
 	}
 
 	// Fallback to looking for a single-auth header (i.e., one config).
-	authConfigs, err = parseSingleAuthHeader(r)
+	authConfig, err := parseSingleAuthHeader(r)
 	if err != nil {
 		return nil, "", err
 	}
-	var conf *types.DockerAuthConfig
+	return &authConfig, "", nil
-	for k := range authConfigs {
-		c := authConfigs[k]
-		conf = &c
-		break
-	}
-	return conf, "", nil
 }
 
 // Header builds the requested Authentication Header
@@ -321,7 +315,7 @@ func imageAuthToDockerAuth(authConfig types.DockerAuthConfig) dockerAPITypes.Aut
 
 // parseSingleAuthHeader extracts a DockerAuthConfig from the request's header.
 // The header content is a single DockerAuthConfig.
-func parseSingleAuthHeader(r *http.Request) (map[string]types.DockerAuthConfig, error) {
+func parseSingleAuthHeader(r *http.Request) (types.DockerAuthConfig, error) {
 	authHeader := r.Header.Get(string(XRegistryAuthHeader))
 	authConfig := dockerAPITypes.AuthConfig{}
 	// Accept "null" and handle it as empty value for compatibility reason with Docker.
@@ -329,12 +323,10 @@ func parseSingleAuthHeader(r *http.Request) (map[string]types.DockerAuthConfig,
 	if len(authHeader) > 0 && authHeader != "null" {
 		authJSON := base64.NewDecoder(base64.URLEncoding, strings.NewReader(authHeader))
 		if err := json.NewDecoder(authJSON).Decode(&authConfig); err != nil {
-			return nil, err
+			return types.DockerAuthConfig{}, err
 		}
 	}
-	authConfigs := make(map[string]types.DockerAuthConfig)
+	return dockerAuthToImageAuth(authConfig), nil
-	authConfigs["0"] = dockerAuthToImageAuth(authConfig)
-	return authConfigs, nil
 }
 
 // parseMultiAuthHeader extracts a DockerAuthConfig from the request's header.

pkg/auth/auth_test.go

@@ -302,24 +302,22 @@ func TestParseSingleAuthHeader(t *testing.T) {
 	for _, tc := range []struct {
 		input     string
 		shouldErr bool
-		expected  map[string]types.DockerAuthConfig
+		expected  types.DockerAuthConfig
 	}{
 		{
 			input:    "", // An empty (or missing) header
-			expected: map[string]types.DockerAuthConfig{"0": {}},
+			expected: types.DockerAuthConfig{},
 		},
 		{
 			input:    "null",
-			expected: map[string]types.DockerAuthConfig{"0": {}},
+			expected: types.DockerAuthConfig{},
 		},
 		// Invalid JSON
 		{input: "@", shouldErr: true},
 		// Success
 		{
-			input: base64.URLEncoding.EncodeToString([]byte(`{"username":"u1","password":"p1"}`)),
+			input:    base64.URLEncoding.EncodeToString([]byte(`{"username":"u1","password":"p1"}`)),
-			expected: map[string]types.DockerAuthConfig{
+			expected: types.DockerAuthConfig{Username: "u1", Password: "p1"},
-				"0": {Username: "u1", Password: "p1"},
-			},
 		},
 	} {
 		req, err := http.NewRequest(http.MethodPost, "/", nil)