Catch errors on TCP/UDP socket closing to prevent requeuing of events (…

…#100)

Relates to #98.

logstash_async/transport.py

@@ -135,8 +135,7 @@ def _close(self, force=False):
             if self._sock:
                 try:
                     self._wait_for_socket_buffer_empty()
-                    self._sock.shutdown(socket.SHUT_WR)
-                    self._sock.close()
+                    self._try_to_close_socket()
                 finally:
                     self._sock = None
 
@@ -162,6 +161,19 @@ def _is_sock_write_buff_empty(self):
         buffer_size = struct.unpack('I', ioctl_result)[0]
         return not buffer_size
 
+    # ----------------------------------------------------------------------
+    def _try_to_close_socket(self):
+        try:
+            self._sock.shutdown(socket.SHUT_WR)
+            self._sock.close()
+        except Exception as exc:
+            self._log_close_socket_error(exc)
+
+    # ----------------------------------------------------------------------
+    def _log_close_socket_error(self, exc):
+        msg = f'Error on closing the transport socket: {exc}'
+        logger.warning(msg)
+
     # ----------------------------------------------------------------------
     def close(self):
         self._close(force=True)