fix: poll for introspection data on startup

Starting the DBus service via systemd and getting the introspection data
is a non atomic operation. The start call can return before the service
is fully running. As the introspection data is acquired from the DBus
service and not from the broker service, this call is not delayed until
the service is responding.

This exposes a more fundamental issue: Introspection and DBus activation
is simply incompatible.

To mitigate this, we retry the introspection for some time after
startup.

Signed-off-by: Felix Moessbauer <[email protected]>

linux-entra-sso.py

@@ -13,6 +13,7 @@
 import struct
 import uuid
 import ctypes
+import time
 from signal import SIGINT
 from threading import Thread, Lock
 from gi.repository import GLib
@@ -27,6 +28,7 @@
 # value can be used, if no real value is provided.
 SSO_URL_DEFAULT = "https://login.microsoftonline.com/"
 EDGE_BROWSER_CLIENT_ID = "d7b530a4-7680-4c23-a8bf-c52c121d2e87"
+BROKER_START_TIMEOUT = 5
 # dbus start service reply codes
 START_REPLY_SUCCESS = 1
 START_REPLY_ALREADY_RUNNING = 2
@@ -94,7 +96,13 @@ def _check_broker_online(self):
             self.broker_online = False
 
     def _instantiate_broker(self):
-        self.broker = self._bus.get(self.BROKER_NAME, self.BROKER_PATH)
+        timeout = time.time() + BROKER_START_TIMEOUT
+        while not self.broker and time.time() < timeout:
+            try:
+                self.broker = self._bus.get(self.BROKER_NAME, self.BROKER_PATH)
+            except GLib.Error:
+                time.sleep(0.1)
+                pass
 
     def _monitor_bus(self):
         self._bus.subscribe(