Add termination handler support

Add support for yate clients to handle the situation
that yate has closed the connection to us.

Make callgen script make use of this and terminate upon yate
connection closing.

Author: garw

yate/asyncio.py

@@ -20,6 +20,7 @@ def __init__(self, host=None, port=None, sockpath=None):
         self.writer = None
         self.main_task = None
         self._automatic_bufsize = False
+        self._termination_handler = None
 
         if host is not None:
             self.mode = self.MODE_TCP
@@ -34,6 +35,9 @@ def __init__(self, host=None, port=None, sockpath=None):
     def run(self, application_main):
         asyncio.run(self._amain(application_main))
 
+    def set_termination_handler(self, termination_handler):
+        self._termination_handler = termination_handler
+
     async def _amain(self, application_main):
         if self.mode == self.MODE_STDIO:
             await self.setup_for_stdio()
@@ -108,7 +112,8 @@ def deferred_msg_write(_param, _value, _success):
         logger.debug("> %s", repr(msg))
 
     async def _yate_stream_closed(self):
-        pass
+        if self._termination_handler is not None:
+            self._termination_handler()
 
     async def drain(self):
         await self.writer.drain()

yate/callgen.py

@@ -29,6 +29,7 @@ def __init__(self, port, sounds_directory, bind_global=False):
 
         self.active_calls = {}
         self.yate = YateAsync("127.0.0.1", port)
+        self.yate.set_termination_handler(self.termination_handler)
         self.sounds_directory = sounds_directory
 
         self.web_app = web.Application()
@@ -71,6 +72,12 @@ async def application_main(self, yate):
     def shutdown(self):
         self.shutdown_future.set_result(True)
 
+    @staticmethod
+    def termination_handler():
+        logging.info("Yate has closed the connection. Terminating application.")
+        os._exit(1)
+
+
     async def web_call_handler(self, request):
         params = await request.post()