more fixes to the backup contract (#281)

This PR irons out the last issues with the backup contract and the
Restic implementation.
I could check it works backing up files to a local folder and to
Backblaze on my server.

lib/default.nix

@@ -9,7 +9,7 @@ rec {
   # - resultPath is the location the config file should have on the filesystem.
   # - generator is a function taking two arguments name and value and returning path in the nix
   #   nix store where the
-  replaceSecrets = { userConfig, resultPath, generator }:
+  replaceSecrets = { userConfig, resultPath, generator, user ? null, permissions ? "u=r,g=r,o=" }:
     let
       configWithTemplates = withReplacements userConfig;
 
@@ -20,6 +20,7 @@ rec {
       replaceSecretsScript {
         file = nonSecretConfigFile;
         inherit resultPath replacements;
+        inherit user permissions;
       };
 
   replaceSecretsFormatAdapter = format: format.generate;
@@ -30,7 +31,7 @@ rec {
     resultPath = newPath;
   };
 
-  replaceSecretsScript = { file, resultPath, replacements }:
+  replaceSecretsScript = { file, resultPath, replacements, user ? null, permissions ? "u=r,g=r,o=" }:
     let
       templatePath = resultPath + ".template";
       sedPatterns = lib.strings.concatStringsSep " " (lib.attrsets.mapAttrsToList (from: to: "-e \"s|${from}|${to}|\"") replacements);
@@ -44,7 +45,12 @@ rec {
       mkdir -p $(dirname ${templatePath})
       ln -fs ${file} ${templatePath}
       rm -f ${resultPath}
+      touch ${resultPath}
+      '' + (lib.optionalString (user != null) ''
+      chown ${user} ${resultPath}
+      '') + ''
       ${sedCmd} ${templatePath} > ${resultPath}
+      chmod ${permissions} ${resultPath}
       '';
 
   secretFileType = lib.types.submodule {
@@ -237,13 +243,14 @@ rec {
       pkgs.runCommand "nix-flake-tests-success" { } "echo > $out";
 
 
-  genConfigOutOfBandSystemd = { config, configLocation, generator }:
+  genConfigOutOfBandSystemd = { config, configLocation, generator, user ? null, permissions ? "u=r,g=r,o=" }:
     {
       loadCredentials = getLoadCredentials "source" config;
       preStart = lib.mkBefore (replaceSecrets {
         userConfig = updateToLoadCredentials "source" "$CREDENTIALS_DIRECTORY" config;
         resultPath = configLocation;
         inherit generator;
+        inherit user permissions;
       });
     };
 

modules/blocks/ldap.nix

@@ -106,6 +106,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "lldap";
         sourceDirectories = [
           "/var/lib/lldap"
         ];
@@ -139,10 +140,7 @@ in
       group = "lldap";
       isSystemUser = true;
     };
-
+    users.groups.lldap = {};
-    users.groups.lldap = {
-      members = [ "backup" ];
-    };
 
     services.lldap = {
       enable = true;

modules/blocks/restic.nix

@@ -15,22 +15,9 @@ let
 
     user = lib.mkOption {
       description = ''
-        Unix user doing the backups.
+        Unix user doing the backups. Must be the user owning the files to be backed up.
-
-        For Restic, the same user must be used for all instances.
       '';
       type = lib.types.str;
-      default = cfg.user;
-    };
-
-    group = lib.mkOption {
-      description = ''
-        Unix group doing the backups.
-
-        For Restic, the same group must be used for all instances.
-      '';
-      type = lib.types.str;
-      default = cfg.group;
     };
 
     sourceDirectories = lib.mkOption {
@@ -125,18 +112,6 @@ let
 in
 {
   options.shb.restic = {
-    user = lib.mkOption {
-      description = "Unix user doing the backups.";
-      type = lib.types.str;
-      default = "backup";
-    };
-
-    group = lib.mkOption {
-      description = "Unix group doing the backups.";
-      type = lib.types.str;
-      default = "backup";
-    };
-
     instances = lib.mkOption {
       description = "Each instance is a backup setting";
       default = {};
@@ -176,41 +151,24 @@ in
       enabledInstances = lib.attrsets.filterAttrs (k: i: i.enable) cfg.instances;
     in lib.mkMerge [
       {
-        assertions = [
+        environment.systemPackages = lib.optionals (enabledInstances != {}) [ pkgs.restic ];
-          {
+
-            assertion = lib.all (x: x.user == cfg.user) (lib.mapAttrsToList (n: v: v)cfg.instances);
+        systemd.tmpfiles.rules =
-            message = "All Restic instances must have the same user as 'shb.restic.user'.";
+          let
-          }
+            mkRepositorySettings = name: instance: repository: lib.optionals (lib.hasPrefix "/" repository.path) [
-          {
+              "d '${repository.path}' 0750 ${instance.user} root - -"
-            assertion = lib.all (x: x.group == cfg.group) (lib.mapAttrsToList (n: v: v) cfg.instances);
-            message = "All Restic instances must have the same group as 'shb.restic.group'.";
-          }
             ];
 
-        users.users = {
+            mkSettings = name: instance: builtins.map (mkRepositorySettings name instance) instance.repositories;
-          ${cfg.user} = {
+          in
-            name = cfg.user;
+            lib.flatten (lib.attrsets.mapAttrsToList mkSettings enabledInstances);
-            group = cfg.group;
-            home = lib.mkForce "/var/lib/${cfg.user}";
-            createHome = true;
-            isSystemUser = true;
-            extraGroups = [ "keys" ];
-          };
-        };
-        users.groups = {
-          ${cfg.group} = {
-            name = cfg.group;
-          };
-        };
-      }
-      {
-        environment.systemPackages = lib.optionals (enabledInstances != {}) [ pkgs.restic ];
 
         services.restic.backups =
           let
             mkRepositorySettings = name: instance: repository: {
               "${name}_${repoSlugName repository.path}" = {
-                inherit (cfg) user;
+                inherit (instance) user;
+
                 repository = repository.path;
 
                 paths = instance.sourceDirectories;
@@ -250,12 +208,13 @@ in
                         Nice = cfg.performance.niceness;
                         IOSchedulingClass = cfg.performance.ioSchedulingClass;
                         IOSchedulingPriority = cfg.performance.ioPriority;
+                        BindReadOnlyPaths = instance.sourceDirectories;
                       };
                     }
                     (lib.attrsets.optionalAttrs (repository.secrets != {})
                       {
                         serviceConfig.EnvironmentFile = [
-                          "/run/secrets/restic/${serviceName}"
+                          "/run/secrets_restic/${serviceName}"
                         ];
                         after = [ "${serviceName}-pre.service" ];
                         requires = [ "${serviceName}-pre.service" ];
@@ -266,8 +225,9 @@ in
                     (let
                       script = shblib.genConfigOutOfBandSystemd {
                         config = repository.secrets;
-                        configLocation = "/run/secrets/restic/${serviceName}";
+                        configLocation = "/run/secrets_restic/${serviceName}";
                         generator = name: v: pkgs.writeText "template" (lib.generators.toINIWithGlobalSection {} { globalSection = v; });
+                        user = instance.user;
                       };
                     in
                       {

modules/blocks/restic/docs/default.md

@@ -18,18 +18,18 @@ Integration tests are defined in [`/test/blocks/restic.nix`](@REPO@/test/blocks/
 
 The following snippet shows how to configure
 the backup of 1 folder to 1 repository.
-
+We assume that the folder is used by the `myservice` service and is owned by a user of the same name.
-Assumptions:
-- 1 hard drive pool is used for backup and is mounted on `/srv/pool1`.
 
 ```nix
-shb.restic.instances.myfolder = {
+shb.restic.instances.myservice = {
   enable = true;
 
+  user = "myservice";
+
   passphraseFile = "<path/to/passphrase>";
 
   repositories = [{
-    path = "/srv/pool1/backups/myfolder";
+    path = "/srv/backups/myservice";
     timerConfig = {
       OnCalendar = "00:00:00";
       RandomizedDelaySec = "3h";
@@ -47,17 +47,9 @@ shb.restic.instances.myfolder = {
     keep_weekly = 4;
     keep_monthly = 6;
   };
-
-  consistency = {
-    repository = "2 weeks";
-    archives = "1 month";
-  };
 };
 ```
 
-To be secure, the `passphraseFile` must contain a secret that is deployed out of band, otherwise it will be world-readable in the nix store.
-To achieve that, I recommend [sops](usage.html#usage-secrets) although other methods work great too.
-
 ### One folder backed up to S3 {#blocks-restic-usage-remote}
 
 Here we will only highlight the differences with the previous configuration.
@@ -65,7 +57,7 @@ Here we will only highlight the differences with the previous configuration.
 This assumes you have access to such a remote S3 store, for example by using [Backblaze](https://www.backblaze.com/).
 
 ```diff
-  shb.backup.instances.myfolder = {
+  shb.backup.instances.myservice = {
 
     repositories = [{
 -     path = "/srv/pool1/backups/myfolder";
@@ -83,6 +75,48 @@ This assumes you have access to such a remote S3 store, for example by using [Ba
   }
 ```
 
+### Secrets {#blocks-restic-secrets}
+
+To be secure, the secrets should deployed out of band, otherwise they will be world-readable in the nix store.
+
+To achieve that, I recommend [sops](usage.html#usage-secrets) although other methods work great too.
+The code to backup to Backblaze with secrets stored in Sops would look like so:
+
+```nix
+shb.restic.instances.myfolder.passphraseFile = config.sops.secrets."myservice/backup/passphrase".path;
+shb.restic.instances.myfolder.repositories = [
+  {
+    path = "s3:s3.us-west-000.backblazeb2.com/<mybucket>";
+    secrets = {
+      AWS_ACCESS_KEY_ID.source = config.sops.secrets."backup/b2/access_key_id".path;
+      AWS_SECRET_ACCESS_KEY.source = config.sops.secrets."backup/b2/secret_access_key".path;
+    };
+  }
+];
+
+sops.secrets."myservice/backup/passphrase" = {
+  sopsFile = ./secrets.yaml;
+  mode = "0400";
+  owner = "myservice";
+  group = "myservice";
+};
+sops.secrets."backup/b2/access_key_id" = {
+  sopsFile = ./secrets.yaml;
+  mode = "0400";
+  owner = "myservice";
+  group = "myservice";
+};
+sops.secrets."backup/b2/secret_access_key" = {
+  sopsFile = ./secrets.yaml;
+  mode = "0400";
+  owner = "myservice";
+  group = "myservice";
+};
+```
+
+Pay attention that the owner must be the `myservice` user, the one owning the files to be backed up.
+A `secrets` contract is in progress that will allow one to not care about such details.
+
 ### Multiple directories to multiple destinations {#blocks-restic-usage-multiple}
 
 The following snippet shows how to configure backup of any number of folders to 3 repositories,
@@ -151,11 +185,6 @@ backupcfg = repositories: name: sourceDirectories {
     keep_monthly = 6;
   };
 
-  consistency = {
-    repository = "2 weeks";
-    archives = "1 month";
-  };
-
   environmentFile = true;
 };
 ```

modules/contracts/backup.nix

@@ -6,13 +6,6 @@ lib.types.submodule {
     user = lib.mkOption {
       description = "Unix user doing the backups.";
       type = lib.types.str;
-      default = "backup";
-    };
-
-    group = lib.mkOption {
-      description = "Unix group doing the backups.";
-      type = lib.types.str;
-      default = "backup";
     };
 
     sourceDirectories = lib.mkOption {
@@ -26,18 +19,6 @@ lib.types.submodule {
       default = [];
     };
 
-    retention = lib.mkOption {
-      description = "Backup files retention.";
-      type = lib.types.attrsOf (lib.types.oneOf [ lib.types.int lib.types.nonEmptyStr ]);
-      default = {
-        keep_within = "1d";
-        keep_hourly = 24;
-        keep_daily = 7;
-        keep_weekly = 4;
-        keep_monthly = 6;
-      };
-    };
-
     hooks = lib.mkOption {
       description = "Hooks to run around the backup.";
       default = {};

modules/contracts/backup/docs/default.md

@@ -4,6 +4,11 @@ This NixOS contract represents a backup job
 that will backup one or more files or directories
 at a regular schedule.
 
+It is a contract between a service that has files to be backed up
+and a service that backs up files.
+All options in this contract should be set by the former.
+The latter will then use the values of those options to know what to backup.
+
 ## Contract Reference {#backup-contract-options}
 
 These are all the options that are expected to exist for this contract to be respected.
@@ -16,41 +21,85 @@ source: @OPTIONS_JSON@
 
 ## Usage {#backup-contract-usage}
 
-A service that can be backed up will provide a `backup` option, like for the [Vaultwarden service][vaultwarden-service-backup].
+A service that can be backed up will provide a `backup` option.
-What this option defines is an implementation detail of that service
+What this option defines is, from the user perspective - that is _you_ - an implementation detail
-but it will at least define what directories to backup
+but it will at least define what directories to backup,
+the user to backup with
 and possibly hooks to run before or after the backup job runs.
 
-[vaultwarden-service-backup]: services-vaultwarden.html#services-vaultwarden-options-shb.vaultwarden.backup
+Here is an example module defining such a `backup` option:
 
 ```nix
-shb.<service>.backup
+{
-```
+  options = {
-
+    myservice.backup = lib.mkOption {
-Let's assume a module implementing this contract is available under the `shb.<backup_impl>` variable.
+      type = contracts.backup;
-Then, to actually backup the service, one would write:
+      readOnly = true;
-
+      default = {
-```nix
+        user = "myservice";
-shb.<backup_impl>.instances."<service>" = shb.<service>.backup // {
+        sourceDirectories = [
-  enable = true;
+          "/var/lib/myservice"
-
+        ];
-  # Options specific to backup_impl
+      };
+    };
+  };
 };
 ```
 
-Then, for extra caution, a second backup could be made using another module `shb.<backup_impl_2>`:
+As you can see, NixOS modules are a bit abused to make contracts work.
+Default values are set as well as the `readOnly` attribute to ensure those values stay as defined.
+
+Now, on the other side we have a service that uses this `backup` option and actually backs up files.
+Let's assume such a module is available under the `backupservice` option
+and that one can create multiple backup instances under `backupservice.instances`.
+Then, to actually backup the `myservice` service, one would write:
 
 ```nix
-shb.<backup_impl_2>.instances."<service>" = shb.<service>.backup // {
+backupservice.instances.myservice = myservice.backup // {
   enable = true;
 
-  # Options specific to backup_impl_2
+  repository = {
+    path = "/srv/backup/myservice";
+  };
+
+  # ... Other options specific to backupservice like scheduling.
 };
 ```
 
+It is advised to backup files to different location, to improve redundancy.
+Thanks to using contracts, this can be made easily either with the same `backupservice`:
+
+```nix
+backupservice.instances.myservice_2 = myservice.backup // {
+  enable = true;
+
+  repository = {
+    path = "<remote path>";
+  };
+};
+```
+
+Or with another module `backupservice_2`!
+
 ## Provided Implementations {#backup-contract-impl}
 
+An implementation here is a service that understands the `backup` contract
+and will backup the files accordingly.
+
 One implementation is provided out of the box:
 - [Restic block](blocks-restic.html).
 
 A second one based on `borgbackup` is in progress.
+
+## Services Providing `backup` Option {#backup-contract-services}
+
+- <!-- [ -->Audiobookshelf<!-- ](services-audiobookshelf.html). --> (no manual yet)
+- <!-- [ -->Deluge<!--](services-deluge.html). --> (no manual yet)
+- <!-- [ -->Grocy<!--](services-grocy.html). --> (no manual yet)
+- <!-- [ -->Hledger<!--](services-hledger.html). --> (no manual yet)
+- <!-- [ -->Home Assistant<!--](services-home-assistant.html). --> (no manual yet)
+- <!-- [ -->Jellyfin<!--](services-jellyfin.html). --> (no manual yet)
+- <!-- [ -->LLDAP<!--](blocks-ldap.html). --> (no manual yet)
+- [Nextcloud](services-nextcloud.html#services-nextcloud-server-usage-backup).
+- [Vaultwarden](services-vaultwarden.html#services-vaultwarden-backup).
+- <!-- [ -->*arr<!--](services-arr.html). --> (no manual yet)

modules/services/arr.nix

@@ -277,20 +277,6 @@ let
     ];
   };
 
-  backup = name: {
-    systemd.tmpfiles.rules = [
-      "d '${config.shb.arr.${name}.dataDir}' 0750 ${config.services.${name}.user} ${config.services.${name}.group} - -"
-    ];
-    users.groups.${name} = {
-      members = [ "backup" ];
-    };
-    systemd.services.${name}.serviceConfig = {
-      # Setup permissions needed for backups, as the backup user is member of the jellyfin group.
-      UMask = lib.mkForce "0027";
-      StateDirectoryMode = lib.mkForce "0750";
-    };
-  };
-
   appOption = name: c: lib.nameValuePair name (lib.mkOption {
     description = "Configuration for ${name}";
     default = {};
@@ -347,6 +333,7 @@ let
           '';
           readOnly = true;
           default = {
+            user = name;
             sourceDirectories = [
               cfg.${name}.dataDir
             ];
@@ -386,7 +373,6 @@ in
 
       shb.nginx.vhosts = [ (vhosts {} cfg') ];
     }))
-    (lib.mkIf cfg.radarr.enable (backup "radarr"))
 
     (lib.mkIf cfg.sonarr.enable (
     let
@@ -416,7 +402,6 @@ in
 
       shb.nginx.vhosts = [ (vhosts {} cfg') ];
     }))
-    (lib.mkIf cfg.sonarr.enable (backup "sonarr"))
 
     (lib.mkIf cfg.bazarr.enable (
     let
@@ -443,7 +428,6 @@ in
 
       shb.nginx.vhosts = [ (vhosts {} cfg') ];
     }))
-    (lib.mkIf cfg.bazarr.enable (backup "bazarr"))
 
     (lib.mkIf cfg.readarr.enable (
     let
@@ -465,7 +449,6 @@ in
 
       shb.nginx.vhosts = [ (vhosts {} cfg') ];
     }))
-    (lib.mkIf cfg.readarr.enable (backup "readarr"))
 
     (lib.mkIf cfg.lidarr.enable (
     let
@@ -492,7 +475,6 @@ in
 
       shb.nginx.vhosts = [ (vhosts {} cfg') ];
     }))
-    (lib.mkIf cfg.lidarr.enable (backup "lidarr"))
 
     (lib.mkIf cfg.jackett.enable (
     let
@@ -503,6 +485,7 @@ in
         enable = true;
         dataDir = "/var/lib/jackett";
       };
+      # TODO: avoid implicitly relying on the media group
       users.users.jackett = {
         extraGroups = [ "media" ];
       };
@@ -516,6 +499,5 @@ in
         extraBypassResources = [ "^/dl.*" ];
       } cfg') ];
     }))
-    (lib.mkIf cfg.jackett.enable (backup "jackett"))
   ];
 }

modules/services/audiobookshelf.nix

@@ -100,6 +100,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "audiobookshelf";
         sourceDirectories = [
           "/var/lib/audiobookshelf"
         ];
@@ -162,17 +163,6 @@ in
         ];
       }
     ];
-    
-    # We want audiobookshelf to create files in the media group and to make those files group readable.
-    users.users.audiobookshelf = {
-      extraGroups = [ "media" ];
-    };
-    systemd.services.audiobookshelfd.serviceConfig.Group = lib.mkForce "media";
-    systemd.services.audiobookshelfd.serviceConfig.UMask = lib.mkForce "0027";
-
-    # We backup the whole audiobookshelf directory and set permissions for the backup user accordingly.
-    users.groups.audiobookshelf.members = [ "backup" ];
-    users.groups.media.members = [ "backup" ];
   } {
     systemd.services.audiobookshelfd.serviceConfig = cfg.extraServiceConfig;
   }]);

modules/services/deluge.nix

@@ -251,6 +251,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "deluge";
         sourceDirectories = [
           cfg.dataDir
         ];
@@ -373,17 +374,6 @@ in
         inherit (cfg) authEndpoint;
       }))
     ];
-
-    # We want deluge to create files in the media group and to make those files group readable.
-    users.users.deluge = {
-      extraGroups = [ "media" ];
-    };
-    systemd.services.deluged.serviceConfig.Group = lib.mkForce "media";
-    systemd.services.deluged.serviceConfig.UMask = lib.mkForce "0027";
-
-    # We backup the whole deluge directory and set permissions for the backup user accordingly.
-    users.groups.deluge.members = [ "backup" ];
-    users.groups.media.members = [ "backup" ];
   } {
     systemd.services.deluged.serviceConfig = cfg.extraServiceConfig;
   } (lib.mkIf (config.shb.deluge.prometheusScraperPasswordFile != null) {

modules/services/grocy.nix

@@ -80,6 +80,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "grocy";
         sourceDirectories = [
           cfg.dataDir
         ];
@@ -115,10 +116,6 @@ in
       sslCertificate = lib.mkIf (!(isNull cfg.ssl)) cfg.ssl.paths.cert;
       sslCertificateKey = lib.mkIf (!(isNull cfg.ssl)) cfg.ssl.paths.key;
     };
-
-    # We backup the whole grocy directory and set permissions for the backup user accordingly.
-    users.groups.grocy.members = [ "backup" ];
-    users.groups.media.members = [ "backup" ];
   } {
     systemd.services.grocyd.serviceConfig = cfg.extraServiceConfig;
   }]);

modules/services/hledger.nix

@@ -72,6 +72,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "hledger";
         sourceDirectories = [
           cfg.dataDir
         ];

modules/services/home-assistant.nix

@@ -154,6 +154,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "hass";
         # No need for backup hooks as we use an hourly automation job in home assistant directly with a cron job.
         sourceDirectories = [
           "/var/lib/hass/backups"
@@ -322,22 +323,5 @@ in
       "f ${config.services.home-assistant.configDir}/scenes.yaml      0755 hass hass"
       "f ${config.services.home-assistant.configDir}/scripts.yaml     0755 hass hass"
     ];
-
-    # Adds the "backup" user to the "hass" group.
-    users.groups.hass = {
-      members = [ "backup" ];
-    };
-
-    # This allows the "backup" user, member of the "backup" group, to access what's inside the home
-    # folder, which is needed for accessing the "backups" folder. It allows to read (r), enter the
-    # directory (x) but not modify what's inside.
-    users.users.hass.homeMode = "0750";
-
-    systemd.services.home-assistant.serviceConfig = {
-      # This allows all members of the "hass" group to read files, list directories and enter
-      # directories created by the home-assistant service. This is needed for the "backup" user,
-      # member of the "hass" group, to backup what is inside the "backup/" folder.
-      UMask = lib.mkForce "0027";
-    };
   };
 }

modules/services/jellyfin.nix

@@ -138,6 +138,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "jellyfin";
         sourceDirectories = [
           "/var/lib/jellyfin"
         ];
@@ -153,16 +154,6 @@ in
       allowedUDPPorts = [ 1900 7359 ];
     };
 
-    users.groups = {
-      media = {
-        name = "media";
-        members = [ "jellyfin" ];
-      };
-      jellyfin = {
-        members = [ "backup" ];
-      };
-    };
-
     services.nginx.enable = true;
 
     # Take advice from https://jellyfin.org/docs/general/networking/nginx/ and https://nixos.wiki/wiki/Plex
@@ -432,13 +423,5 @@ in
         redirect_uris = [ "https://${cfg.subdomain}.${cfg.domain}/sso/OID/r/${cfg.sso.provider}" ];
       }
     ];
-
-    # For backup
-
-    systemd.services.jellyfin.serviceConfig = {
-      # Setup permissions needed for backups, as the backup user is member of the jellyfin group.
-      UMask = lib.mkForce "0027";
-      StateDirectoryMode = lib.mkForce "0750";
-    };
   };
 }

modules/services/nextcloud-server.nix

@@ -515,6 +515,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "nextcloud";
         sourceDirectories = [
           cfg.dataDir
         ];
@@ -568,12 +569,6 @@ in
         };
       };
 
-      # users.groups = {
-      #   nextcloud = {
-      #     members = [ "backup" ];
-      #   };
-      # };
-
       # LDAP is manually configured through
       # https://github.com/lldap/lldap/blob/main/example_configs/nextcloud.md, see also
       # https://docs.nextcloud.com/server/latest/admin_manual/configuration_user/user_auth_ldap.html
@@ -708,10 +703,6 @@ in
 
       services.postgresql.settings = lib.mkIf (! (isNull cfg.postgresSettings)) cfg.postgresSettings;
 
-      systemd.services.phpfpm-nextcloud.serviceConfig = {
-        # Setup permissions needed for backups, as the backup user is member of the jellyfin group.
-        UMask = lib.mkForce "0027";
-      };
       systemd.services.phpfpm-nextcloud.preStart = ''
       mkdir -p /var/log/xdebug; chown -R nextcloud: /var/log/xdebug
       '';

modules/services/nextcloud-server/docs/default.md

@@ -275,9 +275,19 @@ shb.nextcloud.postgresSettings = {
 };
 ```
 
-### Backup the Nextcloud data {#services-nextcloud-server-usage-backup}
+### Backup {#services-nextcloud-server-usage-backup}
 
-TODO
+Backing up Nextcloud using the [Restic block](blocks-restic.html) is done like so:
+
+```nix
+shb.restic.instances."nextcloud" = config.shb.nextcloud.backup // {
+  enable = true;
+};
+```
+
+The name `"nextcloud"` in the `instances` can be anything.
+The `config.shb.nextcloud.backup` option provides what directories to backup.
+You can define any number of Restic instances to backup Nextcloud multiple times.
 
 ### Enable Preview Generator App {#services-nextcloud-server-usage-previewgenerator}
 

modules/services/vaultwarden.nix

@@ -132,6 +132,7 @@ in
       '';
       readOnly = true;
       default = {
+        user = "vaultwarden";
         sourceDirectories = [
           dataFolder
         ];
@@ -224,17 +225,6 @@ in
         passwordFile = builtins.toString cfg.databasePasswordFile;
       }
     ];
-
-    systemd.services.vaultwarden.serviceConfig.UMask = lib.mkForce "0027";
-    # systemd.services.vaultwarden.serviceConfig.Group = lib.mkForce "media";
-    users.users.vaultwarden = {
-      extraGroups = [ "media" ];
-    };
-
-    users.groups.vaultwarden = {
-      members = [ "backup" ];
-    };
-
     # TODO: make this work.
     # It does not work because it leads to infinite recursion.
     # ${cfg.mount}.path = dataFolder;

test/blocks/restic.nix

@@ -8,20 +8,15 @@ let
   base = testLib.base [
     ../../modules/blocks/restic.nix
   ];
-in
+
-{
+  commonTest = user: pkgs.testers.runNixOSTest {
-  backupAndRestore = pkgs.testers.runNixOSTest {
+    name = "restic_backupAndRestore_${user}";
-    name = "restic_backupAndRestore";
 
     nodes.machine = {
       imports = ( testLib.baseImports pkgs' ) ++ [
         ../../modules/blocks/restic.nix
       ];
 
-      shb.restic = {
-        user = "root";
-        group = "root";
-      };
       shb.restic.instances."testinstance" = {
         enable = true;
 
@@ -32,6 +27,8 @@ in
           "/opt/files/B"
         ];
 
+        user = user;
+
         repositories = [
           {
             path = "/opt/repos/A";
@@ -42,8 +39,8 @@ in
             # Those are not needed by the repository but are still included
             # so we can test them in the hooks section.
             secrets = {
-              A.source = pkgs.writeText "A" "secretA";
+              A.source = "/run/secrets/A";
-              B.source = pkgs.writeText "B" "secretB";
+              B.source = "/run/secrets/B";
             };
           }
           {
@@ -58,7 +55,7 @@ in
         hooks.before_backup = [''
           echo $RUNTIME_DIRECTORY
           if [ "$RUNTIME_DIRECTORY" = /run/restic-backups-testinstance_opt_repos_A ]; then
-          if ! [ -f /run/secrets/restic/restic-backups-testinstance_opt_repos_A ]; then
+            if ! [ -f /run/secrets_restic/restic-backups-testinstance_opt_repos_A ]; then
               exit 10
             fi
             if [ -z "$A" ] || ! [ "$A" = "secretA" ]; then
@@ -66,7 +63,7 @@ in
               exit 11
             fi
             if [ -z "$B" ] || ! [ "$B" = "secretB" ]; then
-            echo "A:$A"
+              echo "B:$B"
               exit 12
             fi
           fi
@@ -77,9 +74,7 @@ in
     extraPythonPackages = p: [ p.dictdiffer ];
     skipTypeCheck = true;
 
-    testScript = { nodes, ... }: let
+    testScript = ''
-      instanceCfg = nodes.machine.shb.restic.instances."testinstance";
-    in ''
       from dictdiffer import diff
 
       def list_files(dir):
@@ -102,19 +97,31 @@ in
           if len(result) > 0:
               raise Exception("Unexpected files:", result)
 
+      with subtest("Create secrets"):
+          print(machine.succeed("""
+          mkdir -p /run/secrets/
+
+          echo secretA > /run/secrets/A
+          echo secretB > /run/secrets/B
+
+          chown root:keys -R /run/secrets
+          find /run/secrets -type d -exec chmod u=rwx,g=rx,o=x '{}' ';'
+          find /run/secrets -type f -exec chmod u=r,g=r,o= '{}' ';'
+          ls -l /run/secrets
+          """))
+
       with subtest("Create initial content"):
           machine.succeed("""
           mkdir -p /opt/files/A
           mkdir -p /opt/files/B
-        mkdir -p /opt/repos/A
-        mkdir -p /opt/repos/B
 
           echo repoA_fileA_1 > /opt/files/A/fileA
           echo repoA_fileB_1 > /opt/files/A/fileB
           echo repoB_fileA_1 > /opt/files/B/fileA
           echo repoB_fileB_1 > /opt/files/B/fileB
 
-        # chown :backup -R /opt/files
+          chown ${user}: -R /opt/files
+          chmod go-rwx -R /opt/files
           """)
 
           assert_files("/opt/files", {
@@ -176,5 +183,10 @@ in
               '/opt/files/A/fileB': 'repoA_fileB_2',
           })
       '';
+
   };
+in
+{
+  backupAndRestoreRoot = commonTest "root";
+  backupAndRestoreUser = commonTest "nobody";
 }

test/modules/arr.nix

@@ -56,15 +56,8 @@ in
 
   testRadarr = {
     expected = {
-      systemd.services.radarr = {
+      users = {};
-        serviceConfig = {
+      systemd.services.radarr = {};
-          StateDirectoryMode = "0750";
-          UMask = "0027";
-        };
-      };
-      systemd.tmpfiles.rules = [
-        "d '/var/lib/radarr' 0750 radarr radarr - -"
-      ];
       shb.nginx.vhosts = [
         {
           autheliaRules = [
@@ -90,7 +83,6 @@ in
           ssl = null;
         }
       ];
-      users.groups.radarr.members = [ "backup" ];
       services.nginx.enable = true;
       services.bazarr = {};
       services.jackett = {};
@@ -122,15 +114,8 @@ in
 
   testRadarrWithBackup = {
     expected = {
-      systemd.services.radarr = {
+      users = {};
-        serviceConfig = {
+      systemd.services.radarr = {};
-          StateDirectoryMode = "0750";
-          UMask = "0027";
-        };
-      };
-      systemd.tmpfiles.rules = [
-        "d '/var/lib/radarr' 0750 radarr radarr - -"
-      ];
       shb.nginx.vhosts = [
         {
           autheliaRules = [
@@ -156,7 +141,6 @@ in
           ssl = null;
         }
       ];
-      users.groups.radarr.members = [ "backup" ];
       services.nginx.enable = true;
       services.bazarr = {};
       services.jackett = {};

test/services/vaultwarden.nix

@@ -87,6 +87,25 @@ let
       authEndpoint = "https://${config.shb.authelia.subdomain}.${config.shb.authelia.domain}";
     };
   };
+
+  backup = { config, ... }: {
+    imports = [
+      ../../modules/blocks/restic.nix
+    ];
+    shb.restic.instances."testinstance" = config.shb.vaultwarden.backup // {
+      enable = true;
+      passphraseFile = pkgs.writeText "passphrase" "PassPhrase";
+      repositories = [
+        {
+          path = "/opt/repos/A";
+          timerConfig = {
+            OnCalendar = "00:00:00";
+            RandomizedDelaySec = "5h";
+          };
+        }
+      ];
+    };
+  };
 in
 {
   basic = pkgs.testers.runNixOSTest {
@@ -168,4 +187,25 @@ in
       '';
     };
   };
+
+  backup = pkgs.testers.runNixOSTest {
+    name = "vaultwarden_backup";
+
+    nodes.server = { config, ... }: {
+      imports = [
+        base
+        basic
+        backup
+      ];
+    };
+
+    nodes.client = {};
+
+    testScript = commonTestScript.override {
+      extraScript = { proto_fqdn, ... }: ''
+      with subtest("backup"):
+          server.succeed("systemctl start restic-backups-testinstance_opt_repos_A")
+      '';
+    };
+  };
 }