l 3: add fetchWallpaper.nix

lass/3modules/default.nix

@@ -8,5 +8,6 @@ _:
     ./urxvtd.nix
     ./xresources.nix
     ./wordpress_nginx.nix
+    ./fetchWallpaper.nix
   ];
 }

lass/3modules/fetchWallpaper.nix

@@ -0,0 +1,89 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.lass.fetchWallpaper;
+
+  out = {
+    options.lass.fetchWallpaper = api;
+    config = mkIf cfg.enable imp;
+  };
+
+  api = {
+    enable = mkEnableOption "fetch wallpaper";
+    predicate = mkOption {
+      type = with types; nullOr path;
+      default = null;
+    };
+    url = mkOption {
+      type = types.str;
+    };
+    timerConfig = mkOption {
+      type = types.unspecified;
+      default = {
+        OnCalendar = "*:00,10,20,30,40,50";
+      };
+    };
+    stateDir = mkOption {
+      type = types.str;
+      default = "/tmp/wallpaper";
+    };
+    display = mkOption {
+      type = types.str;
+      default = ":11";
+    };
+  };
+
+  fetchWallpaperScript = pkgs.writeScript "fetchWallpaper" ''
+    #! ${pkgs.bash}/bin/bash
+    ${if (cfg.predicate == null) then "" else ''
+      ${cfg.predicate}
+      if [ $? -ne 0 ]; then
+        echo "predicate failed"
+        exit 23
+      fi
+    ''}
+    mkdir -p ${shell.escape cfg.stateDir}
+    curl -s -o ${shell.escape cfg.stateDir}/wallpaper -z ${shell.escape cfg.stateDir}/wallpaper ${shell.escape cfg.url}
+    feh --no-fehbg --bg-scale ${shell.escape cfg.stateDir}/wallpaper
+  '';
+
+  imp = {
+    users.extraUsers.fetchWallpaper = {
+      name = "fetchWallpaper";
+      uid = 3332383611; #genid fetchWallpaper
+      description = "fetchWallpaper user";
+      home = "/var/empty";
+    };
+
+    systemd.timers.fetchWallpaper = {
+      description = "fetch wallpaper timer";
+      wantedBy = [ "timers.target" ];
+
+      timerConfig = cfg.timerConfig;
+    };
+    systemd.services.fetchWallpaper = {
+      description = "fetch wallpaper";
+      after = [ "network.target" ];
+
+      path = with pkgs; [
+        curl
+        feh
+      ];
+
+      environment = {
+        URL = cfg.url;
+        DISPLAY = cfg.display;
+      };
+
+      restartIfChanged = true;
+
+      serviceConfig = {
+        Type = "simple";
+        ExecStart = fetchWallpaperScript;
+        User = "fetchWallpaper";
+      };
+    };
+  };
+in out