Improve the CLI to handle asyncio.CancelledError properly

Author: RussellLuo

coagent/cli/main.py

@@ -7,6 +7,7 @@
 
 from coagent.core import Address, RawMessage, set_stderr_logger
 from coagent.core.exceptions import BaseError
+from coagent.core.messages import Cancel
 from coagent.runtimes import NATSRuntime, HTTPRuntime
 
 
@@ -68,6 +69,8 @@ async def run(
             else:
                 async for chunk in runtime.channel.publish_multi(addr, msg):
                     print_msg(chunk, oneline, filter)
+        except asyncio.CancelledError:
+            await runtime.channel.publish(addr, Cancel().encode(), probe=False)
         except BaseError as exc:
             print(f"Error: {exc}")