Ray Logging Configuration (#3691)

* fix logging for autoscaler

* module logging

* try this for logging

* yapf

* fix

* Initial logging setup

* momery

* ok

* remove basicconfig

* catch

* remove package logging

* print

* fix

* try_fix

* fix 1

* revert rllib

* logging level

* flake8

* fix

* fix

* Remove vestigal TODO

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
@@ -276,6 +277,33 @@ def resources_from_resource_arguments(default_num_cpus, default_num_gpus,
     return resources
 
 
+_default_handler = None
+
+
+def setup_logger(logging_level, logging_format):
+    """Setup default logging for ray."""
+    logger = logging.getLogger("ray")
+    if type(logging_level) is str:
+        logging_level = logging.getLevelName(logging_level.upper())
+    logger.setLevel(logging_level)
+    global _default_handler
+    _default_handler = logging.StreamHandler()
+    _default_handler.setFormatter(logging.Formatter(logging_format))
+    logger.addHandler(_default_handler)
+    logger.propagate = False
+
+
+def try_update_handler(new_stream):
+    global _default_handler
+    logger = logging.getLogger("ray")
+    if _default_handler:
+        new_handler = logging.StreamHandler(stream=new_stream)
+        new_handler.setFormatter(_default_handler.formatter)
+        _default_handler.close()
+        _default_handler = new_handler
+        logger.addHandler(_default_handler)
+
+
 # This function is copied and modified from
 # https://github.com/giampaolo/psutil/blob/5bd44f8afcecbfb0db479ce230c790fc2c56569a/psutil/tests/test_linux.py#L132-L138  # noqa: E501
 def vmstat(stat):