list which processes occupy port

trap/socket_forwarder.py

@@ -1,8 +1,10 @@
 
 from argparse import Namespace
 import asyncio
+import errno
 import logging
 from multiprocessing import Event
+import subprocess
 from typing import Set, Union, Dict, Any
 from typing_extensions import Self
 
@@ -145,7 +147,14 @@ class WsRouter:
 
         # loop = tornado.ioloop.IOLoop.current()
         logger.info(f"Listen on {self.config.ws_port}")
-        self.application.listen(self.config.ws_port)
+        try:
+            self.application.listen(self.config.ws_port)
+        except OSError as e:
+            if e.errno == errno.EADDRINUSE:
+                logger.critical("Address already in use by process")
+                subprocess.run(["lsof", "-i", f"tcp:{self.config.ws_port:d}"])
+            raise
+
         loop = asyncio.get_event_loop()
 
         task = self.evt_loop.create_task(self.prediction_forwarder())