nixos/nzbget: fix broken service, add a nixos test, as well as some general improvements

nixos/modules/services/misc/nzbget.nix

@@ -4,33 +4,35 @@ with lib;
 
 let
   cfg = config.services.nzbget;
-  dataDir = builtins.dirOf cfg.configFile;
-in {
+  pkg = pkgs.nzbget;
+  stateDir = "/var/lib/nzbget";
+  configFile = "${stateDir}/nzbget.conf";
+  configOpts = concatStringsSep " " (mapAttrsToList (name: value: "-o ${name}=${value}") nixosOpts);
+
+  nixosOpts = {
+    # allows nzbget to run as a "simple" service
+    OutputMode = "loggable";
+    # use journald for logging
+    WriteLog = "none";
+    ErrorTarget = "screen";
+    WarningTarget = "screen";
+    InfoTarget = "screen";
+    DetailTarget = "screen";
+    # required paths
+    ConfigTemplate = "${pkg}/share/nzbget/nzbget.conf";
+    WebDir = "${pkg}/share/nzbget/webui";
+    # nixos handles package updates
+    UpdateCheck = "none";
+  };
+
+in
+{
+  # interface
+
   options = {
     services.nzbget = {
       enable = mkEnableOption "NZBGet";
 
-      package = mkOption {
-        type = types.package;
-        default = pkgs.nzbget;
-        defaultText = "pkgs.nzbget";
-        description = "The NZBGet package to use";
-      };
-
-      dataDir = mkOption {
-        type = types.str;
-        default = "/var/lib/nzbget";
-        description = "The directory where NZBGet stores its configuration files.";
-      };
-
-      openFirewall = mkOption {
-        type = types.bool;
-        default = false;
-        description = ''
-          Open ports in the firewall for the NZBGet web interface
-        '';
-      };
-
       user = mkOption {
         type = types.str;
         default = "nzbget";
@@ -42,15 +44,11 @@ in {
         default = "nzbget";
         description = "Group under which NZBGet runs";
       };
-
-      configFile = mkOption {
-        type = types.str;
-        default = "/var/lib/nzbget/nzbget.conf";
-        description = "Path for NZBGet's config file. (If this doesn't exist, the default config template is copied here.)";
-      };
     };
   };
 
+  # implementation
+
   config = mkIf cfg.enable {
     systemd.services.nzbget = {
       description = "NZBGet Daemon";
@@ -61,50 +59,26 @@ in {
         p7zip
       ];
       preStart = ''
-        cfgtemplate=${cfg.package}/share/nzbget/nzbget.conf
-        if [ ! -f ${cfg.configFile} ]; then
-          echo "${cfg.configFile} not found. Copying default config $cfgtemplate to ${cfg.configFile}"
-          install -m 0700 $cfgtemplate ${cfg.configFile}
-          echo "Setting temporary \$MAINDIR variable in default config required in order to allow nzbget to complete initial start"
-          echo "Remember to change this to a proper value once NZBGet startup has been completed"
-          sed -i -e 's/MainDir=.*/MainDir=\/tmp/g' ${cfg.configFile}
+        if [ ! -f ${configFile} ]; then
+          ${pkgs.coreutils}/bin/install -m 0700 ${pkg}/share/nzbget/nzbget.conf ${configFile}
         fi
       '';
 
-      script = ''
-        args="--daemon --configfile ${cfg.configFile}"
-        # The script in preStart (above) copies nzbget's config template to datadir on first run, containing paths that point to the nzbget derivation installed at the time.
-        # These paths break when nzbget is upgraded & the original derivation is garbage collected. If such broken paths are found in the config file, override them to point to
-        # the currently installed nzbget derivation.
-        cfgfallback () {
-          local hit=`grep -Po "(?<=^$1=).*+" "${cfg.configFile}" | sed 's/[ \t]*$//'` # Strip trailing whitespace
-          ( test $hit && test -e $hit ) || {
-            echo "In ${cfg.configFile}, valid $1 not found; falling back to $1=$2"
-            args+=" -o $1=$2"
-          }
-        }
-        cfgfallback ConfigTemplate ${cfg.package}/share/nzbget/nzbget.conf
-        cfgfallback WebDir ${cfg.package}/share/nzbget/webui
-        ${cfg.package}/bin/nzbget $args
-      '';
-
       serviceConfig = {
-        StateDirectory = dataDir;
-        StateDirectoryMode = "0700";
-        Type = "forking";
+        StateDirectory = "nzbget";
+        StateDirectoryMode = "0750";
         User = cfg.user;
         Group = cfg.group;
-        PermissionsStartOnly = "true";
+        UMask = "0002";
         Restart = "on-failure";
+        ExecStart = "${pkg}/bin/nzbget --server --configfile ${stateDir}/nzbget.conf ${configOpts}";
+        ExecStop = "${pkg}/bin/nzbget --quit";
       };
     };
 
-    networking.firewall = mkIf cfg.openFirewall {
-      allowedTCPPorts = [ 8989 ];
-    };
-
     users.users = mkIf (cfg.user == "nzbget") {
       nzbget = {
+        home = stateDir;
         group = cfg.group;
         uid = config.ids.uids.nzbget;
       };