feat: Add monitoring and automatic restart for bus provider threads

Implemented checks in `MiddlewareDaemon` to monitor the status of
`bp_middleware1` and `bp_ios1` threads. Added automatic restarts for
non-alive threads using `dbus_start`.

Signed-off-by: Sven Sager <s.sager@kunbus.com>

src/revpi_middleware/daemon.py

@@ -129,6 +129,17 @@ class MiddlewareDaemon:
                 self._reconfigure = False
                 pi.startup_complete()
 
+            # Monitor bus providers for errors and restart them
+            restart = False
+            if not (self.bp_middleware1 and self.bp_middleware1.is_alive()):
+                log.warning("dbus middleware1 provider thread is not alive - restarting")
+                restart = True
+            if not (self.bp_ios1 and self.bp_ios1.is_alive()):
+                log.warning("dbus ios1 provider thread is not alive - restarting")
+                restart = True
+            if restart:
+                self.dbus_start()
+
             # Cycle time calculation
             dm = divmod(ot - perf_counter(), self._cycle_time)
             # For float the result is (q, a % b), where q is usually math.floor(a / b) but may be 1 less than that.