Add log rotation (#312)

* Add log rotation

* Add log rotation

Author: qinantong

api/logging_config.py

@@ -1,54 +1,85 @@
 import logging
 import os
 from pathlib import Path
+from logging.handlers import RotatingFileHandler
+
 
 class IgnoreLogChangeDetectedFilter(logging.Filter):
     def filter(self, record: logging.LogRecord):
         return "Detected file change in" not in record.getMessage()
 
+
 def setup_logging(format: str = None):
     """
-    Configure logging for the application.
-    Reads LOG_LEVEL and LOG_FILE_PATH from environment (defaults: INFO, logs/application.log).
-    Ensures log directory exists, and configures both file and console handlers.
+    Configure logging for the application with log rotation.
+
+    Environment variables:
+        LOG_LEVEL: Log level (default: INFO)
+        LOG_FILE_PATH: Path to log file (default: logs/application.log)
+        LOG_MAX_SIZE: Max size in MB before rotating (default: 10MB)
+        LOG_BACKUP_COUNT: Number of backup files to keep (default: 5)
+
+    Ensures log directory exists, prevents path traversal, and configures
+    both rotating file and console handlers.
     """
     # Determine log directory and default file path
     base_dir = Path(__file__).parent
     log_dir = base_dir / "logs"
     log_dir.mkdir(parents=True, exist_ok=True)
     default_log_file = log_dir / "application.log"
 
-    # Get log level and file path from environment
+    # Get log level from environment
     log_level_str = os.environ.get("LOG_LEVEL", "INFO").upper()
     log_level = getattr(logging, log_level_str, logging.INFO)
-    log_file_path = Path(os.environ.get(
-        "LOG_FILE_PATH", str(default_log_file)))
 
-    # ensure log_file_path is within the project's logs directory to prevent path traversal
+    # Get log file path
+    log_file_path = Path(os.environ.get("LOG_FILE_PATH", str(default_log_file)))
+
+    # Secure path check: must be inside logs/ directory
     log_dir_resolved = log_dir.resolve()
     resolved_path = log_file_path.resolve()
     if not str(resolved_path).startswith(str(log_dir_resolved) + os.sep):
-        raise ValueError(
-            f"LOG_FILE_PATH '{log_file_path}' is outside the trusted log directory '{log_dir_resolved}'"
-        )
-    # Ensure parent dirs exist for the log file
+        raise ValueError(f"LOG_FILE_PATH '{log_file_path}' is outside the trusted log directory '{log_dir_resolved}'")
+
+    # Ensure parent directories exist
     resolved_path.parent.mkdir(parents=True, exist_ok=True)
 
-    # Configure logging handlers and format
-    logging.basicConfig(
-        level=log_level,
-        format = format or "%(asctime)s - %(levelname)s - %(name)s - %(filename)s:%(lineno)d - %(message)s",
-        handlers=[
-            logging.FileHandler(resolved_path),
-            logging.StreamHandler()
-        ],
-        force=True
-    )
-    
-    # Ignore log file's change detection
-    for handler in logging.getLogger().handlers:
-        handler.addFilter(IgnoreLogChangeDetectedFilter())
+    # Get max log file size (default: 10MB)
+    try:
+        max_mb = int(os.environ.get("LOG_MAX_SIZE", 10))  # 10MB default
+        max_bytes = max_mb * 1024 * 1024
+    except (TypeError, ValueError):
+        max_bytes = 10 * 1024 * 1024  # fallback to 10MB on error
 
-    # Initial debug message to confirm configuration
+    # Get backup count (default: 5)
+    try:
+        backup_count = int(os.environ.get("LOG_BACKUP_COUNT", 5))
+    except ValueError:
+        backup_count = 5
+
+    # Configure format
+    log_format = format or "%(asctime)s - %(levelname)s - %(name)s - %(filename)s:%(lineno)d - %(message)s"
+
+    # Create handlers
+    file_handler = RotatingFileHandler(resolved_path, maxBytes=max_bytes, backupCount=backup_count, encoding="utf-8")
+    console_handler = logging.StreamHandler()
+
+    # Set format for both handlers
+    formatter = logging.Formatter(log_format)
+    file_handler.setFormatter(formatter)
+    console_handler.setFormatter(formatter)
+
+    # Add filter to suppress "Detected file change" messages
+    file_handler.addFilter(IgnoreLogChangeDetectedFilter())
+    console_handler.addFilter(IgnoreLogChangeDetectedFilter())
+
+    # Apply logging configuration
+    logging.basicConfig(level=log_level, handlers=[file_handler, console_handler], force=True)
+
+    # Log configuration info
     logger = logging.getLogger(__name__)
-    logger.debug(f"Log level set to {log_level_str}, log file: {resolved_path}")
+    logger.debug(
+        f"Logging configured: level={log_level_str}, "
+        f"file={resolved_path}, max_size={max_bytes} bytes, "
+        f"backup_count={backup_count}"
+    )