in callouts/python/extproc/service/callout_server.py [0:0]
def _loop_server(self) -> None:
"""Loop server forever, calling shutdown will cause the server to stop."""
# We chose the main serving thread based on what server configuration
# was requested. Defaults to the health check thread.
if self._health_check_server:
logging.info("Health check server started.")
self._health_check_server.serve_forever()
else:
# If the only server requested is a grpc callout server, we wait on the grpc server.
self._callout_server.loop()