nixos/borgmatic: Allow defining multiple configurations

nixos/doc/manual/release-notes/rl-2305.section.md

@@ -148,6 +148,8 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - NixOS now defaults to using nsncd (a non-caching reimplementation in Rust) as NSS lookup dispatcher, instead of the buggy and deprecated glibc-provided nscd. If you need to switch back, set `services.nscd.enableNsncd = false`, but please open an issue in nixpkgs so your issue can be fixed.
 
+- `services.borgmatic` now allows for multiple configurations, placed in `/etc/borgmatic.d/`, you can define them with `services.borgmatic.configurations`.
+
 - The `dnsmasq` service now takes configuration via the
   `services.dnsmasq.settings` attribute set. The option
   `services.dnsmasq.extraConfig` will be deprecated when NixOS 22.11 reaches

nixos/modules/services/backup/borgmatic.nix

@@ -5,29 +5,21 @@ with lib;
 let
   cfg = config.services.borgmatic;
   settingsFormat = pkgs.formats.yaml { };
-  cfgfile = settingsFormat.generate "config.yaml" cfg.settings;
-in {
-  options.services.borgmatic = {
-    enable = mkEnableOption (lib.mdDoc "borgmatic");
 
-    settings = mkOption {
-      description = lib.mdDoc ''
-        See https://torsion.org/borgmatic/docs/reference/configuration/
-      '';
-      type = types.submodule {
+  cfgType = with types; submodule {
     freeformType = settingsFormat.type;
     options.location = {
       source_directories = mkOption {
-            type = types.listOf types.str;
-            description = lib.mdDoc ''
+        type = listOf str;
+        description = mdDoc ''
           List of source directories to backup (required). Globs and
           tildes are expanded.
         '';
         example = [ "/home" "/etc" "/var/log/syslog*" ];
       };
       repositories = mkOption {
-            type = types.listOf types.str;
-            description = lib.mdDoc ''
+        type = listOf str;
+        description = mdDoc ''
           Paths to local or remote repositories (required). Tildes are
           expanded. Multiple repositories are backed up to in
           sequence. Borg placeholders can be used. See the output of
@@ -37,12 +29,34 @@ in {
           service file to the ReadWritePaths list.
         '';
         example = [
-              "user@backupserver:sourcehostname.borg"
-              "user@backupserver:{fqdn}"
+          "ssh://user@backupserver/./sourcehostname.borg"
+          "ssh://user@backupserver/./{fqdn}"
+          "/var/local/backups/local.borg"
         ];
       };
     };
   };
+
+  cfgfile = settingsFormat.generate "config.yaml" cfg.settings;
+in
+{
+  options.services.borgmatic = {
+    enable = mkEnableOption (mdDoc "borgmatic");
+
+    settings = mkOption {
+      description = mdDoc ''
+        See https://torsion.org/borgmatic/docs/reference/configuration/
+      '';
+      default = null;
+      type = types.nullOr cfgType;
+    };
+
+    configurations = mkOption {
+      description = mdDoc ''
+        Set of borgmatic configurations, see https://torsion.org/borgmatic/docs/reference/configuration/
+      '';
+      default = { };
+      type = types.attrsOf cfgType;
     };
   };
 
@@ -50,9 +64,13 @@ in {
 
     environment.systemPackages = [ pkgs.borgmatic ];
 
-    environment.etc."borgmatic/config.yaml".source = cfgfile;
+    environment.etc = (optionalAttrs (cfg.settings != null) { "borgmatic/config.yaml".source = cfgfile; }) //
+      mapAttrs'
+        (name: value: nameValuePair
+          "borgmatic.d/${name}.yaml"
+          { source = settingsFormat.generate "${name}.yaml" value; })
+        cfg.configurations;
 
     systemd.packages = [ pkgs.borgmatic ];
-
   };
 }