Implement SystemD activation

Closes #369
Closes #433

Author: amezin

Makefile

@@ -192,6 +192,7 @@ PACK_CONTENT += \
 	ddterm/com.github.amezin.ddterm.Extension.xml \
 	ddterm/com.github.amezin.ddterm.desktop.in \
 	ddterm/com.github.amezin.ddterm.service.in \
+	ddterm/dbus-com.github.amezin.ddterm.service.in \
 	LICENSE \
 
 PACK_CONTENT := $(sort $(PACK_CONTENT))

ddterm/app/application.js

@@ -83,6 +83,14 @@ const Application = GObject.registerClass(
                 'Ask the extension to launch the app',
                 null
             );
+            this.add_main_option(
+                'attach-unit',
+                0,
+                GLib.OptionFlags.NONE,
+                GLib.OptionArg.STRING,
+                'Attach launched application process to the specified systemd unit',
+                'UNIT_NAME'
+            );
 
             this.connect('startup', this.startup.bind(this));
             this.connect('handle-local-options', this.handle_local_options.bind(this));
@@ -228,17 +236,30 @@ const Application = GObject.registerClass(
         }
 
         handle_local_options(_, options) {
+            const attach_unit = options.lookup('attach-unit');
+
             if (options.lookup('launch-through-extension')) {
                 try {
-                    const iface = extensiondbus.get();
-                    iface.ServiceSync();
+                    extensiondbus.get().ServiceSync(
+                        attach_unit ? ['--attach-unit', attach_unit] : []
+                    );
+
                     return 0;
                 } catch (e) {
                     logError(e);
                     return 1;
                 }
             }
 
+            if (attach_unit) {
+                try {
+                    this.attach_unit(attach_unit);
+                } catch (e) {
+                    logError(e);
+                    return 1;
+                }
+            }
+
             this.decorated = !options.lookup('undecorated');
 
             if (!(this.flags & Gio.ApplicationFlags.IS_SERVICE))
@@ -247,6 +268,27 @@ const Application = GObject.registerClass(
             return -1;
         }
 
+        attach_unit(unit) {
+            Gio.DBus.session.call_sync(
+                'org.freedesktop.systemd1',
+                '/org/freedesktop/systemd1',
+                'org.freedesktop.systemd1.Manager',
+                'AttachProcessesToUnit',
+                GLib.Variant.new_tuple([
+                    GLib.Variant.new_string(unit),
+                    GLib.Variant.new_string(''),
+                    GLib.Variant.new_array(
+                        new GLib.VariantType('u'),
+                        [GLib.Variant.new_uint32(Gio.Credentials.new().get_unix_pid())]
+                    ),
+                ]),
+                null,
+                Gio.DBusCallFlags.NONE,
+                -1,
+                null
+            );
+        }
+
         preferences() {
             if (this.prefs_dialog === null) {
                 this.prefs_dialog = new PrefsDialog({

ddterm/com.github.amezin.ddterm.Extension.xml

@@ -5,7 +5,9 @@
     <interface name="com.github.amezin.ddterm.Extension">
         <method name="Toggle"/>
         <method name="Activate"/>
-        <method name="Service"/>
+        <method name="Service">
+            <arg type="as" name="args" direction="in"/>
+        </method>
         <method name="MissingDependenciesNotification">
             <arg type="as" name="packages" direction="in"/>
             <arg type="as" name="files" direction="in"/>

ddterm/com.github.amezin.ddterm.service.in

@@ -1,3 +1,4 @@
 [D-BUS Service]
 Name=com.github.amezin.ddterm
 Exec="@LAUNCHER@" --launch-through-extension
+SystemdService=dbus-com.github.amezin.ddterm.service

ddterm/dbus-com.github.amezin.ddterm.service.in

@@ -0,0 +1,5 @@
+[Service]
+Type=forking
+BusName=com.github.amezin.ddterm
+ExecStart="@LAUNCHER@" --launch-through-extension --attach-unit "%n"
+Delegate=

ddterm/shell/extension.js

@@ -44,6 +44,7 @@ let window_connections = null;
 let dbus_interface = null;
 
 let desktop_entry = null;
+let systemd_service = null;
 let dbus_service = null;
 
 const APP_ID = 'com.github.amezin.ddterm';
@@ -127,8 +128,28 @@ class ExtensionDBusInterface {
         activate();
     }
 
-    Service() {
-        spawn_app();
+    ServiceAsync(params, invocation) {
+        const return_error = err => {
+            logError(err);
+
+            if (err instanceof GLib.Error) {
+                invocation.return_gerror(err);
+            } else {
+                let name = err.name;
+                if (!name.includes('.'))
+                    name = `org.gnome.gjs.JSError.${name}`;
+
+                invocation.return_dbus_error(name, err.message);
+            }
+        };
+
+        try {
+            const [args] = params;
+
+            spawn_app(args).then(() => invocation.return_value(null)).catch(return_error);
+        } catch (err) {
+            return_error(err);
+        }
     }
 
     MissingDependenciesNotification(packages, files) {
@@ -146,15 +167,7 @@ class ExtensionDBusInterface {
         for (const filename of files)
             cmd.push('--file', filename);
 
-        const [_, pid] = GLib.spawn_async(
-            null,
-            cmd,
-            null,
-            GLib.SpawnFlags.DEFAULT,
-            null
-        );
-
-        GLib.spawn_close_pid(pid);
+        Gio.Subprocess.new(cmd, Gio.SubprocessFlags.NONE);
     }
 
     GetTargetRect() {
@@ -292,6 +305,31 @@ function enable() {
     );
     desktop_entry.install();
 
+    systemd_service = new InstallableResource(
+        Me.dir.get_child('ddterm').get_child('dbus-com.github.amezin.ddterm.service.in'),
+        Gio.File.new_for_path(GLib.build_filenamev(
+            [
+                GLib.get_user_runtime_dir(),
+                'systemd',
+                'user',
+                `dbus-${APP_ID}.service`,
+            ]))
+    );
+    systemd_service.install();
+
+    Gio.DBus.session.call(
+        'org.freedesktop.systemd1',
+        '/org/freedesktop/systemd1',
+        'org.freedesktop.systemd1.Manager',
+        'Reload',
+        null,
+        null,
+        Gio.DBusCallFlags.NO_AUTO_START,
+        -1,
+        null,
+        null
+    );
+
     dbus_service = new InstallableResource(
         Me.dir.get_child('ddterm').get_child('com.github.amezin.ddterm.service.in'),
         Gio.File.new_for_path(GLib.build_filenamev(
@@ -372,6 +410,11 @@ function disable() {
         desktop_entry = null;
     }
 
+    if (systemd_service) {
+        systemd_service.uninstall();
+        systemd_service = null;
+    }
+
     if (dbus_service) {
         dbus_service.uninstall();
         dbus_service = null;
@@ -380,7 +423,7 @@ function disable() {
     settings = null;
 }
 
-function spawn_app() {
+async function spawn_app(args) {
     if (subprocess)
         return;
 
@@ -393,6 +436,7 @@ function spawn_app() {
         Me.dir.get_child(APP_ID).get_path(),
         '--undecorated',
         '--gapplication-service',
+        ...args,
     ];
 
     if (Meta.is_wayland_compositor()) {
@@ -407,12 +451,35 @@ function spawn_app() {
 
     printerr(`Starting ddterm app: ${JSON.stringify(argv)}`);
 
-    if (wayland_client)
-        subprocess = wayland_client.spawnv(global.display, argv);
-    else
-        subprocess = subprocess_launcher.spawnv(argv);
+    let available_handler = null;
+
+    const registered = new Promise(resolve => {
+        available_handler = app_dbus.connect('notify::available', source => {
+            if (source.available)
+                resolve();
+        });
+    });
+
+    try {
+        if (wayland_client)
+            subprocess = wayland_client.spawnv(global.display, argv);
+        else
+            subprocess = subprocess_launcher.spawnv(argv);
+
+        const terminated = new Promise(resolve => {
+            subprocess.wait_async(null, source => {
+                subprocess_terminated(source);
+                resolve();
+            });
+        });
+
+        await Promise.race([terminated, registered]);
+    } finally {
+        app_dbus.disconnect(available_handler);
+    }
 
-    subprocess.wait_async(null, subprocess_terminated);
+    if (!subprocess)
+        throw new Error('ddterm app exited without acquiring bus name');
 }
 
 function subprocess_terminated(source) {