refactor systemd-unit derivation

Ttrss/update.nix

@@ -1,6 +1,7 @@
 { stdenv
 , pkgs
 , lib
+, utils
 }:
 { readOnlyPaths ? []
 , readWritePaths ? []
@@ -22,9 +23,9 @@ let
   fullPath = "${TtrssService.documentRoot}/${TtrssService.documentName}";
   roPaths = [fullPath] ++ readOnlyPaths;
 in
-stdenv.mkDerivation rec {
+utils.systemd-service-derivation rec {
   name = "ttrss-update";
-  src = pkgs.writeTextDir "${name}.service" ''
+  content = ''
     [Unit]
     Description=${name}
     After=network.target ${TtrssPostgresDB.postgresServiceName}
@@ -60,9 +61,4 @@ stdenv.mkDerivation rec {
     [Install]
     WantedBy=multi-user.target
   '';
-
-  installPhase = ''
-    mkdir -p $out/etc/systemd/system
-    cp $src/*.service $out/etc/systemd/system
-  '';
 }

all-packages.nix

@@ -2,6 +2,7 @@
 , services ? null
 , system ? builtins.currentSystem
 , pkgs ? import <nixpkgs> { inherit system; }
+, utils ? null
 }:
 
 let
@@ -11,7 +12,7 @@ let
     PostgresDB = callPackage ./PostgresDB {};
 
     TtrssService = callPackage ./Ttrss {};
-    TtrssUpdateService = callPackage ./Ttrss/update.nix {};
+    TtrssUpdateService = callPackage ./Ttrss/update.nix {inherit utils;};
     TtrssUpgradeDBService = callPackage ./Ttrss/dbupgrade.nix {};
   };
 in