src/writing_studio/utils/logging.py

"""Structured logging configuration with rotation support."""

import logging
import sys
from logging.handlers import RotatingFileHandler
from pathlib import Path
from typing import Optional

from pythonjsonlogger import jsonlogger

from writing_studio.core.config import settings


class CustomJsonFormatter(jsonlogger.JsonFormatter):
    """Custom JSON formatter with additional fields."""

    def add_fields(self, log_record: dict, record: logging.LogRecord, message_dict: dict) -> None:
        """Add custom fields to log records."""
        super().add_fields(log_record, record, message_dict)
        log_record["level"] = record.levelname
        log_record["logger"] = record.name
        log_record["app"] = settings.app_name
        log_record["environment"] = settings.environment


def setup_logging(
    name: Optional[str] = None,
    level: Optional[str] = None,
    log_file: Optional[str] = None,
) -> logging.Logger:
    """
    Configure structured logging with file rotation.

    Args:
        name: Logger name (default: root logger)
        level: Log level (default: from settings)
        log_file: Log file path (default: from settings)

    Returns:
        Configured logger instance
    """
    logger = logging.getLogger(name)
    logger.setLevel(level or settings.log_level)
    logger.handlers.clear()

    # Console handler
    console_handler = logging.StreamHandler(sys.stdout)
    console_handler.setLevel(level or settings.log_level)

    # Format based on settings
    if settings.log_format == "json":
        formatter = CustomJsonFormatter(
            "%(timestamp)s %(level)s %(name)s %(message)s",
            rename_fields={"timestamp": "asctime"},
        )
    else:
        formatter = logging.Formatter(
            "%(asctime)s - %(name)s - %(levelname)s - %(message)s",
            datefmt="%Y-%m-%d %H:%M:%S",
        )

    console_handler.setFormatter(formatter)
    logger.addHandler(console_handler)

    # File handler with rotation
    log_file_path = log_file or settings.log_file_path
    if log_file_path:
        # Ensure log directory exists
        Path(log_file_path).parent.mkdir(parents=True, exist_ok=True)

        file_handler = RotatingFileHandler(
            log_file_path,
            maxBytes=settings.log_max_bytes,
            backupCount=settings.log_backup_count,
        )
        file_handler.setLevel(level or settings.log_level)
        file_handler.setFormatter(formatter)
        logger.addHandler(file_handler)

    # Prevent propagation to avoid duplicate logs
    logger.propagate = False

    return logger


# Global logger instance
logger = setup_logging("writing_studio")