nixos/airsonic: add module

nixos/modules/module-list.nix

@@ -268,6 +268,7 @@
   ./services/mail/rspamd.nix
   ./services/mail/rmilter.nix
   ./services/mail/nullmailer.nix
+  ./services/misc/airsonic.nix
   ./services/misc/apache-kafka.nix
   ./services/misc/autofs.nix
   ./services/misc/autorandr.nix

nixos/modules/services/misc/airsonic.nix

@@ -0,0 +1,117 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.airsonic;
+in {
+  options = {
+
+    services.airsonic = {
+      enable = mkEnableOption "Airsonic, the Free and Open Source media streaming server (fork of Subsonic and Libresonic)";
+
+      user = mkOption {
+        type = types.str;
+        default = "airsonic";
+        description = "User account under which airsonic runs.";
+      };
+
+      home = mkOption {
+        type = types.path;
+        default = "/var/lib/airsonic";
+        description = ''
+          The directory where Airsonic will create files.
+          Make sure it is writable.
+        '';
+      };
+
+      listenAddress = mkOption {
+        type = types.string;
+        default = "127.0.0.1";
+        description = ''
+          The host name or IP address on which to bind Airsonic.
+          Only relevant if you have multiple network interfaces and want
+          to make Airsonic available on only one of them. The default value
+          will bind Airsonic to all available network interfaces.
+        '';
+      };
+
+      port = mkOption {
+        type = types.int;
+        default = 4040;
+        description = ''
+          The port on which Airsonic will listen for
+          incoming HTTP traffic. Set to 0 to disable.
+        '';
+      };
+
+      contextPath = mkOption {
+        type = types.path;
+        default = "/";
+        description = ''
+          The context path, i.e., the last part of the Airsonic
+          URL. Typically '/' or '/airsonic'. Default '/'
+        '';
+      };
+
+      maxMemory = mkOption {
+        type = types.int;
+        default = 100;
+        description = ''
+          The memory limit (max Java heap size) in megabytes.
+          Default: 100
+        '';
+      };
+
+      transcoders = mkOption {
+        type = types.listOf types.path;
+        default = [ "${pkgs.ffmpeg.bin}/bin/ffmpeg" ];
+        defaultText= [ "\${pkgs.ffmpeg.bin}/bin/ffmpeg" ];
+        description = ''
+          List of paths to transcoder executables that should be accessible
+          from Airsonic. Symlinks will be created to each executable inside
+          ${cfg.home}/transcoders.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.airsonic = {
+      description = "Airsonic Media Server";
+      after = [ "local-fs.target" "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      script = ''
+        ${pkgs.jre}/bin/java -Xmx${toString cfg.maxMemory}m \
+          -Dairsonic.home=${cfg.home} \
+          -Dserver.address=${cfg.listenAddress} \
+          -Dserver.port=${toString cfg.port} \
+          -Dairsonic.contextPath=${cfg.contextPath} \
+          -Djava.awt.headless=true \
+          -verbose:gc \
+          -jar ${pkgs.airsonic}/webapps/airsonic.war
+      '';
+
+      preStart = ''
+        # Install transcoders.
+        ${pkgs.coreutils}/bin/rm -rf ${cfg.home}/transcode
+        ${pkgs.coreutils}/bin/mkdir -p ${cfg.home}/transcode
+        for exe in ${toString cfg.transcoders}; do
+            ${pkgs.coreutils}/bin/ln -sf "$exe" ${cfg.home}/transcode
+        done
+      '';
+      serviceConfig = {
+        Restart = "always";
+        User = "airsonic";
+        UMask = "0022";
+      };
+    };
+
+    users.extraUsers.airsonic = {
+      description = "Airsonic service user";
+      name = cfg.user;
+      home = cfg.home;
+      createHome = true;
+    };
+  };
+}