[Core/RLlib] Move log_once from rllib to ray.util. (#7273)

* Move log_once from rllib to tune.

* Move log_once from rllib to tune.

* LINT.

* Move to ray.util.debug.

python/ray/tune/logger.py

@@ -7,6 +7,7 @@ import numbers
 import numpy as np
 
 import ray.cloudpickle as cloudpickle
+from ray.util.debug import log_once
 from ray.tune.result import (NODE_IP, TRAINING_ITERATION, TIME_TOTAL_S,
                              TIMESTEPS_TOTAL, EXPR_PARAM_FILE,
                              EXPR_PARAM_PICKLE_FILE, EXPR_PROGRESS_FILE,
@@ -214,10 +215,11 @@ class TBXLogger(Logger):
                 # In case TensorboardX still doesn't think it's a valid value
                 # (e.g. `[[]]`), warn and move on.
                 except (ValueError, TypeError):
-                    logger.warning(
-                        "You are trying to log an invalid value ({}={}) "
-                        "via {}!".format(full_attr, value,
-                                         type(self).__name__))
+                    if log_once("invalid_tbx_value"):
+                        logger.warning(
+                            "You are trying to log an invalid value ({}={}) "
+                            "via {}!".format(full_attr, value,
+                                             type(self).__name__))
 
         self.last_result = valid_result
         self._file_writer.flush()

python/ray/tune/utils/__init__.py

@@ -1,9 +1,14 @@
-from ray.tune.utils.util import (deep_update, flatten_dict, get_pinned_object,
-                                 merge_dicts, pin_in_object_store, UtilMonitor,
-                                 validate_save_restore, warn_if_slow)
+from ray.tune.utils.util import deep_update, flatten_dict, get_pinned_object, \
+    merge_dicts, pin_in_object_store, UtilMonitor, validate_save_restore, \
+    warn_if_slow
 
 __all__ = [
-    "deep_update", "flatten_dict", "get_pinned_object", "merge_dicts",
-    "pin_in_object_store", "UtilMonitor", "validate_save_restore",
-    "warn_if_slow"
+    "deep_update",
+    "flatten_dict",
+    "get_pinned_object",
+    "merge_dicts",
+    "pin_in_object_store",
+    "UtilMonitor",
+    "validate_save_restore",
+    "warn_if_slow",
 ]

python/ray/util/__init__.py

@@ -1,10 +1,15 @@
-from .named_actors import get_actor, register_actor
-from .actor_pool import ActorPool
-from . import iter
+from ray.util import iter
+from ray.util.actor_pool import ActorPool
+from ray.util.debug import log_once, disable_log_once_globally, \
+    enable_periodic_logging
+from ray.util.named_actors import get_actor, register_actor
 
 __all__ = [
     "ActorPool",
-    "iter",
+    "disable_log_once_globally",
+    "enable_periodic_logging",
     "get_actor",
+    "iter",
+    "log_once",
     "register_actor",
 ]

python/ray/util/debug.py

@@ -0,0 +1,46 @@
+import time
+
+_logged = set()
+_disabled = False
+_periodic_log = False
+_last_logged = 0.0
+
+
+def log_once(key):
+    """Returns True if this is the "first" call for a given key.
+
+    Various logging settings can adjust the definition of "first".
+
+    Example:
+        >>> if log_once("some_key"):
+        ...     logger.info("Some verbose logging statement")
+    """
+
+    global _last_logged
+
+    if _disabled:
+        return False
+    elif key not in _logged:
+        _logged.add(key)
+        _last_logged = time.time()
+        return True
+    elif _periodic_log and time.time() - _last_logged > 60.0:
+        _logged.clear()
+        _last_logged = time.time()
+        return False
+    else:
+        return False
+
+
+def disable_log_once_globally():
+    """Make log_once() return False in this process."""
+
+    global _disabled
+    _disabled = True
+
+
+def enable_periodic_logging():
+    """Make log_once() periodically return True in this process."""
+
+    global _periodic_log
+    _periodic_log = True