Emit plain file when key is empty

Co-Authored-By: Slaier <slaier@users.noreply.github.com>

README.md

@@ -707,6 +707,44 @@ This is how it can be included in your `configuration.nix`:
 }
 ```
 
+## Emit plain file for yaml and json formats
+
+By default, sops-nix extracts a single key from yaml and json files. If you
+need the plain file instead of extracting a specific key from the input document,
+you can set `key` to an empty string.
+
+For example, the input document `my-config.yaml` likes this:
+
+```yaml
+my-secret1: ENC[AES256_GCM,data:tkyQPQODC3g=,iv:yHliT2FJ74EtnLIeeQtGbOoqVZnF0q5HiXYMJxYx6HE=,tag:EW5LV4kG4lcENaN2HIFiow==,type:str]
+my-secret2: ENC[AES256_GCM,data:tkyQPQODC3g=,iv:yHliT2FJ74EtnLIeeQtGbOoqVZnF0q5HiXYMJxYx6HE=,tag:EW5LV4kG4lcENaN2HIFiow==,type:str]
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+...
+```
+
+This is how it can be included in your NixOS module:
+
+```nix
+{
+  sops.secrets.my-config = {
+    format = "yaml";
+    sopsFile = ./my-config.yaml;
+    key = "";
+  };
+}
+```
+
+Then, it will be mounted as `/run/secrets/my-config`:
+
+```yaml
+my-secret1: hello
+my-secret2: hello
+```
+
 ## Use with home manager
 
 sops-nix also provides a home-manager module.

modules/home-manager/sops.nix

@@ -15,11 +15,12 @@ let
 
       key = lib.mkOption {
         type = lib.types.str;
-        default = name;
+        default = if cfg.defaultSopsKey != null then cfg.defaultSopsKey else name;
         description = ''
           Key used to lookup in the sops file.
           No tested data structures are supported right now.
           This option is ignored if format is binary.
+          "" means whole file.
         '';
       };
 
@@ -131,6 +132,16 @@ in {
       '';
     };
 
+    defaultSopsKey = mkOption {
+      type = lib.types.nullOr lib.types.str;
+      default = null;
+      description = ''
+        Default key used to lookup in all secrets.
+        This option is ignored if format is binary.
+        "" means whole file.
+      '';
+    };
+
     validateSopsFiles = lib.mkOption {
       type = lib.types.bool;
       default = true;

modules/sops/default.nix

@@ -41,11 +41,12 @@ let
       };
       key = lib.mkOption {
         type = lib.types.str;
-        default = config._module.args.name;
+        default = if cfg.defaultSopsKey != null then cfg.defaultSopsKey else config._module.args.name;
         description = ''
           Key used to lookup in the sops file.
           No tested data structures are supported right now.
           This option is ignored if format is binary.
+          "" means whole file.
         '';
       };
       path = lib.mkOption {
@@ -176,6 +177,16 @@ in {
       '';
     };
 
+    defaultSopsKey = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      default = null;
+      description = ''
+        Default key used to lookup in all secrets.
+        This option is ignored if format is binary.
+        "" means whole file.
+      '';
+    };
+
     validateSopsFiles = lib.mkOption {
       type = lib.types.bool;
       default = true;

pkgs/sops-install-secrets/main.go

@@ -294,12 +294,20 @@ func decryptSecret(s *secret, sourceFiles map[string]plainData) error {
 		case Binary, Dotenv, Ini:
 			sourceFile.binary = plain
 		case Yaml:
-			if err := yaml.Unmarshal(plain, &sourceFile.data); err != nil {
+			if s.Key == "" {
-				return fmt.Errorf("cannot parse yaml of '%s': %w", s.SopsFile, err)
+				sourceFile.binary = plain
+			} else {
+				if err := yaml.Unmarshal(plain, &sourceFile.data); err != nil {
+					return fmt.Errorf("Cannot parse yaml of '%s': %w", s.SopsFile, err)
+				}
 			}
 		case JSON:
-			if err := json.Unmarshal(plain, &sourceFile.data); err != nil {
+			if s.Key == "" {
-				return fmt.Errorf("cannot parse json of '%s': %w", s.SopsFile, err)
+				sourceFile.binary = plain
+			} else {
+				if err := json.Unmarshal(plain, &sourceFile.data); err != nil {
+					return fmt.Errorf("Cannot parse json of '%s': %w", s.SopsFile, err)
+				}
 			}
 		default:
 			return fmt.Errorf("secret of type %s in %s is not supported", s.Format, s.SopsFile)
@@ -309,11 +317,15 @@ func decryptSecret(s *secret, sourceFiles map[string]plainData) error {
 	case Binary, Dotenv, Ini:
 		s.value = sourceFile.binary
 	case Yaml, JSON:
-		strVal, err := recurseSecretKey(sourceFile.data, s.Key)
+		if s.Key == "" {
-		if err != nil {
+			s.value = sourceFile.binary
-			return fmt.Errorf("secret %s in %s is not valid: %w", s.Name, s.SopsFile, err)
+		} else {
+			strVal, err := recurseSecretKey(sourceFile.data, s.Key)
+			if err != nil {
+				return fmt.Errorf("secret %s in %s is not valid: %w", s.Name, s.SopsFile, err)
+			}
+			s.value = []byte(strVal)
 		}
-		s.value = []byte(strVal)
 	}
 	sourceFiles[s.SopsFile] = sourceFile
 	return nil
@@ -482,7 +494,7 @@ func (app *appContext) validateSopsFile(s *secret, file *secretFile) error {
 			s.Name, s.SopsFile, s.Format,
 			file.firstSecret.Format, file.firstSecret.Name)
 	}
-	if app.checkMode != Manifest && (s.Format != Binary && s.Format != Dotenv && s.Format != Ini) {
+	if app.checkMode != Manifest && !(s.Format == Binary || s.Format == Dotenv || s.Format == Ini) && s.Key != "" {
 		_, err := recurseSecretKey(file.keys, s.Key)
 		if err != nil {
 			return fmt.Errorf("secret %s in %s is not valid: %w", s.Name, s.SopsFile, err)