Fix multi-thread problem of function manager and Jenkins test (#3648)

python/ray/utils.py

@@ -6,6 +6,7 @@ import binascii
 import functools
 import hashlib
 import inspect
+import logging
 import numpy as np
 import os
 import subprocess
@@ -18,6 +19,8 @@ import ray.gcs_utils
 import ray.raylet
 import ray.ray_constants as ray_constants
 
+logger = logging.getLogger(__name__)
+
 
 def _random_string():
     id_hash = hashlib.sha1()
@@ -69,6 +72,8 @@ def push_error_to_driver(worker,
     if driver_id is None:
         driver_id = ray_constants.NIL_JOB_ID.id()
     data = {} if data is None else data
+    logging.error("Pushing error to dirver, type: %s, message: %s.",
+                  error_type, message)
     worker.raylet_client.push_error(
         ray.ObjectID(driver_id), error_type, message, time.time())