Repository: modin-project/modin

Issue:
Unify type of log_level in logging module
**Is your feature request related to a problem? Please describe.**
A clear and concise description of what the problem is. What kind of performance improvements would you like to see with this new API?

The logging module currently has a handful of functions that take in a `log_level` argument that are ints in some functions and string in other functions. For example, `_create_logger` in `logging/config.py` has `log_level` as an integer where as `class_logger.py` takes in `log_level` as a string. This isn't a terribly pressing issue, but we should try to decide on one type for `log_level` or handle both integers and strings elegantly. 


Discussion:

Resolving patch:
diff --git a/modin/logging/class_logger.py b/modin/logging/class_logger.py
--- a/modin/logging/class_logger.py
+++ b/modin/logging/class_logger.py
@@ -19,6 +19,7 @@
 
 from typing import Dict, Optional
 
+from .config import LogLevel
 from .logger_decorator import enable_logging
 
 
@@ -38,7 +39,7 @@ def __init_subclass__(
         cls,
         modin_layer: Optional[str] = None,
         class_name: Optional[str] = None,
-        log_level: str = "info",
+        log_level: LogLevel = LogLevel.INFO,
         **kwargs: Dict,
     ) -> None:
         """
@@ -51,8 +52,8 @@ def __init_subclass__(
         class_name : str, optional
             The name of the class the decorator is being applied to.
             Composed from the decorated class name if not specified.
-        log_level : str, default: "info"
-            The log level (INFO, DEBUG, WARNING, etc.).
+        log_level : LogLevel, default: LogLevel.INFO
+            The log level (LogLevel.INFO, LogLevel.DEBUG, LogLevel.WARNING, etc.).
         **kwargs : dict
         """
         modin_layer = modin_layer or cls._modin_logging_layer
diff --git a/modin/logging/config.py b/modin/logging/config.py
--- a/modin/logging/config.py
+++ b/modin/logging/config.py
@@ -23,6 +23,7 @@
 import threading
 import time
 import uuid
+from enum import IntEnum
 from logging.handlers import RotatingFileHandler
 from pathlib import Path
 from typing import Optional
@@ -36,6 +37,16 @@
 __LOGGER_CONFIGURED__: bool = False
 
 
+class LogLevel(IntEnum):  # noqa: PR01
+    """Enumerator to specify the valid values of LogLevel accepted by Logger.setLevel()."""
+
+    DEBUG = 10
+    INFO = 20
+    WARNING = 30
+    ERROR = 40
+    CRITICAL = 50
+
+
 class ModinFormatter(logging.Formatter):  # noqa: PR01
     """Implement custom formatter to log at microsecond granularity."""
 
@@ -97,7 +108,7 @@ def bytes_int_to_str(num_bytes: int, suffix: str = "B") -> str:
 
 
 def _create_logger(
-    namespace: str, job_id: str, log_name: str, log_level: int
+    namespace: str, job_id: str, log_name: str, log_level: LogLevel
 ) -> logging.Logger:
     """
     Create and configure logger as Modin expects it to be.
@@ -110,8 +121,7 @@ def _create_logger(
         Part of path to where logs are stored.
     log_name : str
         Name of the log file to create.
-    log_level : int
-        Log level as accepted by `Logger.setLevel()`.
+    log_level : LogLevel
 
     Returns
     -------
@@ -159,7 +169,7 @@ def configure_logging() -> None:
         "modin.logger.default",
         job_id,
         "trace",
-        logging.INFO if LogMode.get() == "enable_api_only" else logging.DEBUG,
+        LogLevel.INFO if LogMode.get() == "enable_api_only" else LogLevel.DEBUG,
     )
 
     logger.info(f"OS Version: {platform.platform()}")
@@ -174,7 +184,7 @@ def configure_logging() -> None:
     if LogMode.get() != "enable_api_only":
         mem_sleep = LogMemoryInterval.get()
         mem_logger = _create_logger(
-            "modin_memory.logger", job_id, "memory", logging.DEBUG
+            "modin_memory.logger", job_id, "memory", LogLevel.DEBUG
         )
 
         svmem = psutil.virtual_memory()
@@ -186,7 +196,7 @@ def configure_logging() -> None:
         )
         mem.start()
 
-    _create_logger("modin.logger.errors", job_id, "error", logging.INFO)
+    _create_logger("modin.logger.errors", job_id, "error", LogLevel.INFO)
 
     __LOGGER_CONFIGURED__ = True
 
diff --git a/modin/logging/logger_decorator.py b/modin/logging/logger_decorator.py
--- a/modin/logging/logger_decorator.py
+++ b/modin/logging/logger_decorator.py
@@ -18,13 +18,12 @@
 """
 
 from functools import wraps
-from logging import Logger
 from types import FunctionType, MethodType
 from typing import Any, Callable, Dict, Optional, Tuple, Type, Union
 
 from modin.config import LogMode
 
-from .config import get_logger
+from .config import LogLevel, get_logger
 
 _MODIN_LOGGER_NOWRAP = "__modin_logging_nowrap__"
 
@@ -50,7 +49,7 @@ def disable_logging(func: Callable) -> Callable:
 def enable_logging(
     modin_layer: Union[str, Callable, Type] = "PANDAS-API",
     name: Optional[str] = None,
-    log_level: str = "info",
+    log_level: LogLevel = LogLevel.INFO,
 ) -> Callable:
     """
     Log Decorator used on specific Modin functions or classes.
@@ -63,8 +62,8 @@ def enable_logging(
     name : str, optional
         The name of the object the decorator is being applied to.
         Composed from the decorated object name if not specified.
-    log_level : str, default: "info"
-        The log level (INFO, DEBUG, WARNING, etc.).
+    log_level : LogLevel, default: LogLevel.INFO
+        The log level (LogLevel.INFO, LogLevel.DEBUG, LogLevel.WARNING, etc.).
 
     Returns
     -------
@@ -77,9 +76,6 @@ def enable_logging(
         # def func()
         return enable_logging()(modin_layer)
 
-    log_level = log_level.lower()
-    assert hasattr(Logger, log_level.lower()), f"Invalid log level: {log_level}"
-
     def decorator(obj: Any) -> Any:
         """Decorate function or class to add logs to Modin API function(s)."""
         if isinstance(obj, type):
@@ -129,8 +125,7 @@ def run_and_log(*args: Tuple, **kwargs: Dict) -> Any:
                 return obj(*args, **kwargs)
 
             logger = get_logger()
-            logger_level = getattr(logger, log_level)
-            logger_level(start_line)
+            logger.log(log_level, start_line)
             try:
                 result = obj(*args, **kwargs)
             except BaseException as e:
@@ -146,7 +141,7 @@ def run_and_log(*args: Tuple, **kwargs: Dict) -> Any:
                     e._modin_logged = True  # type: ignore[attr-defined]
                 raise
             finally:
-                logger_level(stop_line)
+                logger.log(log_level, stop_line)
             return result
 
         # make sure we won't decorate multiple times


Test patch:
diff --git a/modin/test/test_logging.py b/modin/test/test_logging.py
--- a/modin/test/test_logging.py
+++ b/modin/test/test_logging.py
@@ -27,8 +27,8 @@ def __init__(self, namespace):
         self.messages = collections.defaultdict(list)
         self.namespace = namespace
 
-    def info(self, message, *args, **kw):
-        self.messages["info"].append(message.format(*args, **kw))
+    def log(self, log_level, message, *args, **kw):
+        self.messages[log_level].append(message.format(*args, **kw))
 
     def exception(self, message, *args, **kw):
         self.messages["exception"].append(message.format(*args, **kw))
@@ -81,8 +81,8 @@ def func(do_raise):
         with pytest.raises(ValueError):
             func(do_raise=True)
 
-    assert "func" in get_log_messages()["info"][0]
-    assert "START" in get_log_messages()["info"][0]
+    assert "func" in get_log_messages()[logging.INFO][0]
+    assert "START" in get_log_messages()[logging.INFO][0]
     assert get_log_messages("modin.logger.errors")["exception"] == [
         "STOP::PANDAS-API::func"
     ]
@@ -137,7 +137,7 @@ def method4(self):
         Bar().method1()
         Bar().method4()
 
-    assert get_log_messages()["info"] == [
+    assert get_log_messages()[logging.INFO] == [
         "START::CUSTOM::Foo.method1",
         "STOP::CUSTOM::Foo.method1",
         "START::CUSTOM::Foo.method2",
@@ -164,7 +164,7 @@ def method2(self):
         Bar().method1()
         Bar().method2()
 
-    assert get_log_messages()["info"] == [
+    assert get_log_messages()[logging.INFO] == [
         "START::CUSTOM::Foo.method1",
         "STOP::CUSTOM::Foo.method1",
         "START::CUSTOM::Foo.method1",