[QEff. Finetune]: Added logger and its test cases. (#644)

- Added a logger which will log onto console and file. This code is
similar to existing QEff. Finetuning logger code.
- Also added dist_utils which serves as utility code when dealing with
distributed training.
- Added logger test cases for sanity checks.

---------

Signed-off-by: meetkuma <meetkuma@qti.qualcomm.com>

Author: quic-meetkuma

QEfficient/finetune/experimental/core/logger.py

@@ -0,0 +1,170 @@
+# -----------------------------------------------------------------------------
+#
+# Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+# SPDX-License-Identifier: BSD-3-Clause
+#
+# -----------------------------------------------------------------------------
+
+
+import logging
+import sys
+from pathlib import Path
+from typing import Optional
+
+from transformers.utils.logging import get_logger as hf_get_logger
+
+from QEfficient.finetune.experimental.core.utils.dist_utils import get_local_rank
+
+# -----------------------------------------------------------------------------
+# Logger usage:
+# Initialize logger:
+#   logger = Logger("my_logger", log_file="logs/output.log", level=logging.DEBUG)
+# Log messages:
+#   logger.info("This is an info message")
+#   logger.error("This is an error message")
+#   logger.log_rank_zero("This message is logged only on rank 0")
+#   logger.log_exception("An error occurred", exception, raise_exception=False)
+# Attach file handler later if needed:
+#   logger.prepare_for_logs(output_dir="logs", log_level="DEBUG")
+# -----------------------------------------------------------------------------
+
+
+class Logger:
+    """Custom logger with console and file logging capabilities."""
+
+    def __init__(
+        self,
+        name: str = "transformers",  # We are using "transformers" as default to align with HF logs
+        log_file: Optional[str] = None,
+        level: int = logging.INFO,
+    ):
+        """
+        Initialize the logger.
+
+        Args:
+            name: Logger name
+            log_file: Path to log file (if None, log only to console)
+            level: Logging level
+        """
+        self.logger = hf_get_logger(name)
+        self.logger.setLevel(level)
+
+        # Clear any existing handlers
+        self.logger.handlers.clear()
+
+        # Create formatter
+        self.formatter = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
+
+        # Console handler
+        console_handler = logging.StreamHandler(sys.stdout)
+        console_handler.setLevel(level)
+        console_handler.setFormatter(self.formatter)
+        self.logger.addHandler(console_handler)
+
+        # File handler (if log_file is provided)
+        if log_file:
+            # Create directory if it doesn't exist
+            log_path = Path(log_file)
+            log_path.parent.mkdir(parents=True, exist_ok=True)
+
+            file_handler = logging.FileHandler(log_file)
+            file_handler.setLevel(level)
+            file_handler.setFormatter(self.formatter)
+            self.logger.addHandler(file_handler)
+
+    def debug(self, message: str) -> None:
+        """Log debug message."""
+        self.logger.debug(message)
+
+    def info(self, message: str) -> None:
+        """Log info message."""
+        self.logger.info(message)
+
+    def warning(self, message: str) -> None:
+        """Log warning message."""
+        self.logger.warning(message)
+
+    def error(self, message: str) -> None:
+        """Log error message."""
+        self.logger.error(message)
+
+    def critical(self, message: str) -> None:
+        """Log critical message."""
+        self.logger.critical(message)
+
+    def log_rank_zero(self, message: str, level: int = logging.INFO) -> None:
+        """
+        Log message only on rank 0 process.
+
+        Args:
+            message: Message to log
+            level: Logging level
+        """
+        if get_local_rank() == 0:
+            self.logger.log(level, message)
+
+    def log_exception(self, message: str, exception: Exception, raise_exception: bool = True) -> None:
+        """
+        Log exception message and optionally raise the exception.
+
+        Args:
+            message: Custom message to log
+            exception: Exception to log
+            raise_exception: Whether to raise the exception after logging
+        """
+        error_message = f"{message}: {str(exception)}"
+        self.logger.error(error_message)
+
+        if raise_exception:
+            raise exception
+
+    def prepare_for_logs(self, output_dir: Optional[str] = None, log_level: str = "INFO") -> None:
+        """
+        Prepare existing logger to log to both console and file with specified
+        output directory and log level.
+
+        Args:
+            output_dir: Output directory for logs
+            log_level: Logging level as string
+        """
+        # Convert string log level to logging constant
+        level = getattr(logging, log_level.upper(), logging.INFO)
+        self.logger.setLevel(level)
+
+        # Update existing handlers' levels
+        for handler in self.logger.handlers:
+            handler.setLevel(level)
+
+        # Add file handler if saving metrics
+        if output_dir:
+            log_file = Path(output_dir) / "training.log"
+            log_file.parent.mkdir(parents=True, exist_ok=True)
+
+            # Check if file handler already exists
+            file_handler_exists = any(isinstance(handler, logging.FileHandler) for handler in self.logger.handlers)
+
+            if not file_handler_exists:
+                file_handler = logging.FileHandler(log_file)
+                file_handler.setLevel(level)
+                file_handler.setFormatter(self.formatter)
+                self.logger.addHandler(file_handler)
+
+
+# Global logger instance
+_logger: Optional[Logger] = None
+
+
+def get_logger(log_file: Optional[str] = None) -> Logger:
+    """
+    Get or create a logger instance.
+
+    Args:
+        log_file: Path to log file (if None, log only to console)
+
+    Returns:
+        Logger instance
+    """
+    global _logger
+    if _logger is None:
+        _logger = Logger(log_file=log_file)
+    return _logger

QEfficient/finetune/experimental/core/utils/dist_utils.py

@@ -4,3 +4,36 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 # -----------------------------------------------------------------------------
+
+import torch.distributed as dist
+
+
+def is_dist_available_and_initialized() -> bool:
+    """Check if distributed training is available and initialized."""
+    return dist.is_available() and dist.is_initialized()
+
+
+def get_rank() -> int:
+    """Return the global rank of the current process, else 0."""
+    if not is_dist_available_and_initialized():
+        return 0
+    return dist.get_rank()
+
+
+def get_local_rank() -> int:
+    """Return the local rank of the current process on its node, else 0."""
+    if not is_dist_available_and_initialized():
+        return 0
+    return dist.get_node_local_rank()
+
+
+def get_world_size() -> int:
+    """Get the total number of processes in distributed training."""
+    if not is_dist_available_and_initialized():
+        return 1
+    return dist.get_world_size()
+
+
+def is_main_process() -> bool:
+    """Check if the current process is the main process (rank 0)."""
+    return get_rank() == 0