2 files changed, 103 insertions, 0 deletions

diff --git a/custom/borgbackup.nix b/custom/borgbackup.nix
new file mode 100644
index 00000000..49da1975
--- /dev/null
+++ b/custom/borgbackup.nix
@@ -0,0 +1,101 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.borgbackup;
+
+  targetOptions = {
+    options = {
+      repo = mkOption {
+        type = types.str;
+      };
+    
+      paths = mkOption {
+        type = types.listOf types.path;
+        default = [];
+      };
+
+      interval = mkOption {
+        type = types.str;
+        default = "6h";
+      };
+
+      lock = mkOption {
+        type = types.nullOr types.str;
+        default = "backup";
+      };
+
+      network = mkOption {
+        type = types.bool;
+        default = true;
+      };
+    };
+  };
+in {
+  options = {
+    services.borgbackup = {
+      snapshots = mkOption {
+        type = types.nullOr (types.enum ["btrfs"]);
+        default = null;
+      };
+
+      targets = mkOption {
+        type = types.attrsOf (types.submodule targetOptions);
+        default = {};
+      };
+
+      prefix = mkOption {
+        type = types.str;
+      };
+    };
+  };
+
+  config = mkIf (any (t: t.paths != []) cfg.targets) {
+    services.btrfs-snapshots.enable = mkIf (cfg.snapshots == "btrfs") true;
+  
+    systemd.timers = listToAttrs (map (target: path: nameValuePair "borgbackup-${target}@${path}" {
+      wantedBy = [ "timers.target" ];
+
+      timerConfig = {
+        Persistent = true;
+        OnUnitInactiveSec = "6h";
+      };
+    }) (flatten (mapAttrsToList (target: tCfg: map (path: { inherit target path; }) tCfg.paths;) cfg.targets)));
+
+    systemd.services = map (target: nameValuePair "borgbackup-${target}@" (let
+      deps = flatten [
+        optional (cfg.snapshots == "btrfs") "btrfs-snapshot@%i.service"
+        optional network "network-online.target"
+      ];
+    in {
+      bindsTo = deps;
+      after = deps;
+
+      path = with pkgs; [borgbackup];
+
+      script = ''
+        borg create \
+          --stats \
+          --list \
+          --filter 'AME' \
+          --exclude-caches \
+          --keep-exclude-tags \
+          --patterns-from .backup \
+          --one-file-system \
+          --compression auto,lzma \
+          ${target}::${prefix}$1-{utcnow}
+      '';
+      scriptArgs = "%i";
+
+      serviceConfig = {
+        Type = "oneshot";
+        WorkingDirectory = if (cfg.snapshots == null) then "%p" else "/mnt/snapshot-%i";
+        Nice = 15;
+        IOSchedulingClass = 2;
+        IOSchedulingPriority = 7;
+        SuccessExitStatus = [1 2];
+      };
+    })) (attrNames cfg.targets);
+  };
+};
diff --git a/custom/btrfs-snapshots.nix b/custom/btrfs-snapshots.nix
index 03b17d23..7114e9d9 100644
--- a/custom/btrfs-snapshots.nix
+++ b/custom/btrfs-snapshots.nix
@@ -13,11 +13,13 @@ in {
       enable = mkEnableOption "a systemd unit for btrfs snapshots";   
 
       mountPoint = mkOption {
+        readOnly = true;
         type = types.path;
         default = "/mnt";
       };
 
       mountPrefix = mkOption {
+        readOnly = true;
         type = types.str;
         default = "snapshot-";
       };