Fix configuring CLI logging on Python 3.9/3.10 (#2953)

Do not use `logging.getLevelNamesMapping`
introduced in 3.11.

No need to get the numeric levels at all - just
set the configured named levels on the handlers
and set DEBUG on the logger. This way, the logger
allows all messages, but level filtering is then
done by the handlers.

Author: jvstme

src/dstack/_internal/cli/utils/common.py

@@ -1,5 +1,4 @@
 import logging
-import os
 from datetime import datetime, timezone
 from pathlib import Path
 from typing import Any, Dict, Union
@@ -9,6 +8,7 @@
 from rich.table import Table
 from rich.theme import Theme
 
+from dstack._internal import settings
 from dstack._internal.cli.utils.rich import DstackRichHandler
 from dstack._internal.core.errors import CLIError, DstackError
 from dstack._internal.utils.common import get_dstack_dir
@@ -68,29 +68,22 @@ def configure_logging():
 
     log_file = _get_cli_log_file()
 
-    level_names = logging.getLevelNamesMapping()
-    stdout_level_name = os.getenv("DSTACK_CLI_LOG_LEVEL", "INFO").upper()
-    stdout_level = level_names[stdout_level_name]
-    dstack_logger.setLevel(stdout_level)
-
     stdout_handler = DstackRichHandler(console=console)
     stdout_handler.setFormatter(logging.Formatter(fmt="%(message)s", datefmt="[%X]"))
-    stdout_handler.setLevel(stdout_level)
+    stdout_handler.setLevel(settings.CLI_LOG_LEVEL)
     dstack_logger.addHandler(stdout_handler)
 
-    file_level_name = os.getenv("DSTACK_CLI_FILE_LOG_LEVEL", "DEBUG").upper()
-    file_level = level_names[file_level_name]
-
     file_handler = logging.FileHandler(log_file)
     file_handler.setFormatter(
         logging.Formatter(
             fmt="%(asctime)s - %(name)s - %(levelname)s - %(message)s", datefmt="%Y-%m-%d %H:%M:%S"
         )
     )
-    file_handler.setLevel(file_level)
+    file_handler.setLevel(settings.CLI_FILE_LOG_LEVEL)
     dstack_logger.addHandler(file_handler)
 
-    dstack_logger.setLevel(min(stdout_level, file_level))
+    # the logger allows all messages, filtering is done by the handlers
+    dstack_logger.setLevel(logging.DEBUG)
 
 
 def confirm_ask(prompt, **kwargs) -> bool:

src/dstack/_internal/settings.py

@@ -19,6 +19,9 @@
 )
 DSTACK_DIND_IMAGE = os.getenv("DSTACK_DIND_IMAGE", "dstackai/dind")
 
+CLI_LOG_LEVEL = os.getenv("DSTACK_CLI_LOG_LEVEL", "INFO").upper()
+CLI_FILE_LOG_LEVEL = os.getenv("DSTACK_CLI_FILE_LOG_LEVEL", "DEBUG").upper()
+
 # Development settings
 
 LOCAL_BACKEND_ENABLED = os.getenv("DSTACK_LOCAL_BACKEND_ENABLED") is not None