Log traceback upon task error (#8746)

Author: hendrikmakait

distributed/tests/test_worker.py

@@ -878,6 +878,7 @@ async def test_log_exception_on_failed_task(c, s, a, b):
     text = logger.getvalue()
     assert "ZeroDivisionError" in text
     assert "Exception" in text
+    assert "Traceback" in text
 
 
 @gen_cluster(client=True)

distributed/worker.py

@@ -2348,13 +2348,15 @@ async def execute(self, key: Key, *, stimulus_id: str) -> StateMachineEvent:
                     "Function:  %s\n"
                     "args:      %s\n"
                     "kwargs:    %s\n"
-                    "Exception: %r\n",
+                    "Exception: %r\n"
+                    "Traceback: %r\n",
                     key,
                     ts.state,
                     str(funcname(function))[:1000],
                     convert_args_to_str(args2, max_len=1000),
                     convert_kwargs_to_str(kwargs2, max_len=1000),
                     result["exception_text"],
+                    result["traceback_text"],
                 )
 
             return ExecuteFailureEvent.from_exception(