fix(sunshine): stabilize remote Niri sessions

modules/nixos/desktop/networking/remote-desktop.nix

@@ -35,6 +35,7 @@
     capSysAdmin = false;
     openFirewall = true;
     settings = {
+      capture = "wlr";
       # pc  - Only localhost may access the web ui
       # lan - Only LAN devices may access the web ui
       origin_web_ui_allowed = "pc";

modules/nixos/desktop/networking/sunshine/remote-session.nu

@@ -85,18 +85,38 @@ def wait-ready [user: string, machine: string] {
   error make { msg: 'Remote session did not become ready within 30 seconds; inspect journalctl -u greetd-sunshine.service' }
 }
 
-def wait-niri [user: string] {
+def niri-socket [machine: string] {
+  let environment = (^systemctl --machine $machine --user show-environment | complete)
+  if $environment.exit_code != 0 { return '' }
+
+  ($environment.stdout
+    | lines
+    | where { |line| $line starts-with 'NIRI_SOCKET=' }
+    | get 0?
+    | default ''
+    | str replace 'NIRI_SOCKET=' '')
+}
+
+def wait-niri [user: string, machine: string] {
   for _ in 1..30 {
     let greetd = ((^systemctl is-active greetd-sunshine.service | complete).stdout | str trim) == 'active'
     let niri = ((^pgrep -u $user -x niri | complete).exit_code) == 0
-    if $greetd and $niri { return }
+    let socket = (niri-socket $machine)
+    let ipc = if $socket == '' or not ($socket | path exists) {
+      false
+    } else {
+      with-env { NIRI_SOCKET: $socket } {
+        ((^niri msg outputs | complete).exit_code) == 0
+      }
+    }
+    if $greetd and $niri and $ipc { return }
     sleep 1sec
   }
-  error make { msg: 'Niri did not become ready within 30 seconds; inspect journalctl -u greetd-sunshine.service' }
+  error make { msg: 'Niri IPC did not become ready within 30 seconds; inspect journalctl -u greetd-sunshine.service' }
 }
 
 def start-sunshine [machine: string] {
-  ^systemctl --machine $machine --user reset-failed sunshine.service
+  let _ = (^systemctl --machine $machine --user reset-failed sunshine.service | complete)
   ^systemctl --machine $machine --user start sunshine.service
 }
 
@@ -110,7 +130,9 @@ def main [
   let session_user = ($env.SUDO_USER? | default $user)
   let user_machine = (user-machine $session_user)
   # niri-session starts niri.service through the user manager. Run the
-  # compositor directly so greetd owns this temporary session.
+  # compositor directly so greetd owns this temporary session. This
+  # intentionally skips xdg-desktop-autostart.target, keeping XDG autostart
+  # apps such as browsers out of the remote session.
   let command = if $command == '' { '/run/current-system/sw/bin/niri --session' } else { $command }
   let runtime = (preflight $tty $command)
   if $check {
@@ -144,7 +166,7 @@ def main [
     $runtime.greetd
     --config $config)
 
-  wait-niri $session_user
+  wait-niri $session_user $user_machine
   start-sunshine $user_machine
   wait-ready $session_user $user_machine
   print 'Remote Niri and Sunshine session is ready.'