borgmatic: add module

modules/programs/borgmatic.nix

@@ -0,0 +1,196 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.programs.borgmatic;
+
+  mkNullableOption = args:
+    lib.mkOption (args // {
+      type = lib.types.nullOr args.type;
+      default = null;
+    });
+
+  mkRetentionOption = frequency:
+    mkNullableOption {
+      type = types.int;
+      description =
+        "Number of ${frequency} archives to keep. Use -1 for no limit.";
+      example = 3;
+    };
+
+  extraConfigOption = mkOption {
+    type = with types; attrsOf (oneOf [ str bool path int ]);
+    default = { };
+    description = "Extra settings.";
+  };
+
+  consistencyCheckModule = types.submodule {
+    options = {
+      name = mkOption {
+        type = types.enum [ "repository" "archives" "data" "extract" ];
+        description = "Name of consistency check to run.";
+        example = "repository";
+      };
+
+      frequency = mkNullableOption {
+        type = types.strMatching "([[:digit:]]+ .*)|always";
+        description = "Frequency of this type of check";
+        example = "2 weeks";
+      };
+    };
+  };
+
+  configModule = types.submodule {
+    options = {
+      location = {
+        sourceDirectories = mkOption {
+          type = types.listOf types.str;
+          description = "Directories to backup.";
+          example = literalExpression "[config.home.homeDirectory]";
+        };
+
+        repositories = mkOption {
+          type = types.listOf types.str;
+          description = "Paths to repositories.";
+          example =
+            literalExpression ''["ssh://myuser@myrepo.myserver.com/./repo"]'';
+        };
+
+        extraConfig = extraConfigOption;
+      };
+
+      storage = {
+        encryptionPasscommand = mkNullableOption {
+          type = types.str;
+          description = "Command writing the passphrase to standard output.";
+          example =
+            literalExpression ''"''${pkgs.password-store}/bin/pass borg-repo"'';
+        };
+        extraConfig = extraConfigOption;
+      };
+
+      retention = {
+        keepWithin = mkNullableOption {
+          type = types.strMatching "[[:digit:]]+[Hdwmy]";
+          description = "Keep all archives within this time interval.";
+          example = "2d";
+        };
+
+        keepSecondly = mkRetentionOption "secondly";
+        keepMinutely = mkRetentionOption "minutely";
+        keepHourly = mkRetentionOption "hourly";
+        keepDaily = mkRetentionOption "daily";
+        keepWeekly = mkRetentionOption "weekly";
+        keepMonthly = mkRetentionOption "monthly";
+        keepYearly = mkRetentionOption "yearly";
+
+        extraConfig = extraConfigOption;
+      };
+
+      consistency = {
+        checks = mkOption {
+          type = types.listOf consistencyCheckModule;
+          default = [ ];
+          description = "Consistency checks to run";
+          example = literalExpression ''
+            [
+              {
+                name = "repository";
+                frequency = "2 weeks";
+              }
+              {
+                name = "archives";
+                frequency = "4 weeks";
+              }
+              {
+                name = "data";
+                frequency = "6 weeks";
+              }
+              {
+                name = "extract";
+                frequency = "6 weeks";
+              }
+            ];
+          '';
+        };
+
+        extraConfig = extraConfigOption;
+      };
+    };
+  };
+
+  removeNullValues = attrSet: filterAttrs (key: value: value != null) attrSet;
+
+  writeConfig = config:
+    generators.toYAML { } {
+      location = removeNullValues {
+        source_directories = config.location.sourceDirectories;
+        repositories = config.location.repositories;
+      } // config.location.extraConfig;
+      storage = removeNullValues {
+        encryption_passcommand = config.storage.encryptionPasscommand;
+      } // config.storage.extraConfig;
+      retention = removeNullValues {
+        keep_within = config.retention.keepWithin;
+        keep_secondly = config.retention.keepSecondly;
+        keep_minutely = config.retention.keepMinutely;
+        keep_hourly = config.retention.keepHourly;
+        keep_daily = config.retention.keepDaily;
+        keep_weekly = config.retention.keepWeekly;
+        keep_monthly = config.retention.keepMonthly;
+        keep_yearly = config.retention.keepYearly;
+      } // config.retention.extraConfig;
+      consistency = removeNullValues { checks = config.consistency.checks; }
+        // config.consistency.extraConfig;
+    };
+in {
+  meta.maintainers = [ maintainers.DamienCassou ];
+
+  options = {
+    programs.borgmatic = {
+      enable = mkEnableOption "Borgmatic";
+
+      package = mkPackageOption pkgs "borgmatic" { };
+
+      backups = mkOption {
+        type = types.attrsOf configModule;
+        description = ''
+          Borgmatic allows for several named backup configurations,
+          each with its own source directories and repositories.
+        '';
+        example = literalExpression ''
+          {
+            personal = {
+              location = {
+                sourceDirectories = [ "/home/me/personal" ];
+                repositories = [ "ssh://myuser@myserver.com/./personal-repo" ];
+              };
+            };
+            work = {
+              location = {
+                sourceDirectories = [ "/home/me/work" ];
+                repositories = [ "ssh://myuser@myserver.com/./work-repo" ];
+              };
+            };
+          };
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    assertions = [
+      (lib.hm.assertions.assertPlatform "programs.borgmatic" pkgs
+        lib.platforms.linux)
+    ];
+
+    xdg.configFile = with lib.attrsets;
+      mapAttrs' (configName: config:
+        nameValuePair ("borgmatic.d/" + configName + ".yaml") {
+          text = writeConfig config;
+        }) cfg.backups;
+
+    home.packages = [ cfg.package ];
+  };
+}