feat: add centralized logging to replace ad-hoc print statements (#1254)

* feat: add logging utility functions

* feat: add logging setup and log level argument to CLI

* feat: integrate logging across modules

whisperx/log_utils.py

@@ -0,0 +1,67 @@
+import logging
+import sys
+from typing import Optional
+
+_LOG_FORMAT = "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
+_DATE_FORMAT = "%Y-%m-%d %H:%M:%S"
+
+
+def setup_logging(
+    level: str = "info",
+    log_file: Optional[str] = None,
+) -> None:
+    """
+    Configure logging for WhisperX.
+
+    Args:
+        level: Logging level (debug, info, warning, error, critical). Default: info
+        log_file: Optional path to log file. If None, logs only to console.
+    """
+    logger = logging.getLogger("whisperx")
+
+    logger.handlers.clear()
+
+    try:
+        log_level = getattr(logging, level.upper())
+    except AttributeError:
+        log_level = logging.WARNING
+    logger.setLevel(log_level)
+
+    formatter = logging.Formatter(_LOG_FORMAT, datefmt=_DATE_FORMAT)
+
+    console_handler = logging.StreamHandler(sys.stdout)
+    console_handler.setLevel(log_level)
+    console_handler.setFormatter(formatter)
+
+    logger.addHandler(console_handler)
+
+    if log_file:
+        try:
+            file_handler = logging.FileHandler(log_file)
+            file_handler.setLevel(log_level)
+            file_handler.setFormatter(formatter)
+            logger.addHandler(file_handler)
+        except (OSError) as e:
+            logger.warning(f"Failed to create log file '{log_file}': {e}")
+            logger.warning("Continuing with console logging only")
+
+    # Don't propagate to root logger to avoid duplicate messages
+    logger.propagate = False
+
+
+def get_logger(name: str) -> logging.Logger:
+    """
+    Get a logger instance for the given module.
+
+    Args:
+        name: Logger name (typically __name__ from calling module)
+
+    Returns:
+        Logger instance configured with WhisperX settings
+    """
+    whisperx_logger = logging.getLogger("whisperx")
+    if not whisperx_logger.handlers:
+        setup_logging()
+
+    logger_name = "whisperx" if name == "__main__" else name
+    return logging.getLogger(logger_name)