Reduce RLlib log verbosity (#6154)

doc/source/rllib-training.rst

@@ -567,13 +567,18 @@ You can use the `data output API <rllib-offline.html>`__ to save episode traces
 Log Verbosity
 ~~~~~~~~~~~~~
 
-You can control the trainer log level via the ``"log_level"`` flag. Valid values are "INFO" (default), "DEBUG", "WARN", and "ERROR". This can be used to increase or decrease the verbosity of internal logging. For example:
+You can control the trainer log level via the ``"log_level"`` flag. Valid values are "DEBUG", "INFO", "WARN" (default), and "ERROR". This can be used to increase or decrease the verbosity of internal logging. You can also use the ``-v`` and ``-vv`` flags. For example, the following two commands are about equivalent:
 
 .. code-block:: bash
 
     rllib train --env=PongDeterministic-v4 \
         --run=A2C --config '{"num_workers": 2, "log_level": "DEBUG"}'
 
+    rllib train --env=PongDeterministic-v4 \
+        --run=A2C --config '{"num_workers": 2}' -vv
+
+The default log level is ``WARN``. We strongly recommend using at least ``INFO`` level logging for development.
+
 Stack Traces
 ~~~~~~~~~~~~
 

rllib/agents/trainer.py

@@ -47,7 +47,7 @@ COMMON_CONFIG = {
     # Should be one of DEBUG, INFO, WARN, or ERROR. The DEBUG level will also
     # periodically print out summaries of relevant internal dataflow (this is
     # also printed out once at startup at the INFO level).
-    "log_level": "INFO",
+    "log_level": "WARN",
     # Callbacks that will be run during various phases of training. These all
     # take a single "info" dict as an argument. For episode callbacks, custom
     # metrics can be attached to the episode by updating the episode object's
@@ -479,6 +479,11 @@ class Trainer(Trainable):
         self.raw_user_config = config
         self.config = merged_config
         Trainer._validate_config(self.config)
+        log_level = self.config.get("log_level")
+        if log_level in ["WARN", "ERROR"]:
+            logger.info("Current log_level is {}. For more information, "
+                        "set 'log_level': 'INFO' / 'DEBUG' or use the -v and "
+                        "-vv flags.".format(log_level))
         if self.config.get("log_level"):
             logging.getLogger("ray.rllib").setLevel(self.config["log_level"])
 

rllib/train.py

@@ -88,6 +88,10 @@ def create_parser(parser_creator=None):
         default="",
         type=str,
         help="Optional URI to sync training results to (e.g. s3://bucket).")
+    parser.add_argument(
+        "-v", action="store_true", help="Whether to use INFO level logging.")
+    parser.add_argument(
+        "-vv", action="store_true", help="Whether to use DEBUG level logging.")
     parser.add_argument(
         "--resume",
         action="store_true",
@@ -143,6 +147,7 @@ def run(args, parser):
             }
         }
 
+    verbose = 1
     for exp in experiments.values():
         if not exp.get("run"):
             parser.error("the following arguments are required: --run")
@@ -150,6 +155,12 @@ def run(args, parser):
             parser.error("the following arguments are required: --env")
         if args.eager:
             exp["config"]["eager"] = True
+        if args.v:
+            exp["config"]["log_level"] = "INFO"
+            verbose = 2
+        if args.vv:
+            exp["config"]["log_level"] = "DEBUG"
+            verbose = 3
         if args.trace:
             if not exp["config"].get("eager"):
                 raise ValueError("Must enable --eager to enable tracing.")
@@ -178,6 +189,7 @@ def run(args, parser):
         scheduler=_make_scheduler(args),
         queue_trials=args.queue_trials,
         resume=args.resume,
+        verbose=verbose,
         concurrent=True)