logs: Add colored output

Make the log output colored depending on the log level. This will make
it much easier to quickly spot errors and warnings in the output, and
also looks cooler.

Control characters for colors are only added if the output is a TTY, so
the output can be redirected to a file without any issues.

Signed-off-by: Mykyta Poturai <[email protected]>

moulin/log_utils.py

@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright 2024 EPAM Systems
+
+
+import logging
+import sys
+
+
+class ColoredFormatter(logging.Formatter):
+    # Define color codes
+    COLORS = {
+        'DEBUG': '\033[94m',      # Blue
+        'INFO': '\033[92m',       # Green
+        'WARNING': '\033[93m',    # Yellow
+        'ERROR': '\033[91m',      # Red
+        'CRITICAL': '\033[1;91m'  # Bold Red
+    }
+    RESET = '\033[0m'  # Reset color
+
+    def format(self, record):
+        log_color = self.COLORS.get(record.levelname, self.RESET)
+        message = super().format(record)
+
+        if sys.stderr.isatty():
+            return f"{log_color}{message}{self.RESET}"
+        else:
+            return message
+
+
+def build_handlers(log_format: str) -> list[logging.Handler]:
+    formatter = ColoredFormatter(log_format)
+    handler = logging.StreamHandler()
+    handler.setFormatter(formatter)
+    return [handler]

moulin/main.py

@@ -23,6 +23,7 @@
 from moulin.build_conf import MoulinConfiguration
 import moulin.rouge
 import moulin.rouge.block_entry
+from moulin.log_utils import build_handlers
 
 log = logging.getLogger(__name__)
 
@@ -88,7 +89,7 @@ def _handle_shared_opts(description: str,
     loglevel = logging.INFO
     if args.verbose:
         loglevel = logging.DEBUG
-    logging.basicConfig(level=loglevel, format="[%(levelname)s] %(message)s")
+    logging.basicConfig(level=loglevel, handlers=build_handlers("[%(levelname)s] %(message)s"))
 
     local_conf_file = _get_conf_file(args.conf)