fix: allow only standard registry by default if no policy file is set

pkg/policy/config_reader.go

@@ -32,6 +32,9 @@ func (reader *MockConfigReader) Read(files []string) ([]*Config, error) {
 }
 
 func (reader *ConfigReaderImpl) Read(files []string) ([]*Config, error) {
+	if len(files) == 0 {
+		return reader.readDefault()
+	}
 	policyCfgs := make([]*Config, len(files))
 	for i, cfgFilePath := range files {
 		policyCfg := &Config{
@@ -46,6 +49,31 @@ func (reader *ConfigReaderImpl) Read(files []string) ([]*Config, error) {
 	return policyCfgs, nil
 }
 
+func (reader *ConfigReaderImpl) readDefault() ([]*Config, error) {
+	// https://github.com/aquaproj/aqua/issues/1404
+	// If no policy file is set, only standard registry is allowed by default.
+	cfg := &Config{
+		YAML: &ConfigYAML{
+			Registries: []*Registry{
+				{
+					Type: "standard",
+				},
+			},
+			Packages: []*Package{
+				{
+					RegistryName: "standard",
+				},
+			},
+		},
+	}
+	if err := cfg.Init(); err != nil {
+		return nil, err
+	}
+	return []*Config{
+		cfg,
+	}, nil
+}
+
 func (reader *ConfigReaderImpl) read(cfg *Config) error {
 	file, err := reader.fs.Open(cfg.Path)
 	if err != nil {