"""
Logging configuration for imagen-mcp.
Configures:
- Human-readable rotating log file: `imagen-mcp.log`
- Structured JSONL events log: `events.jsonl`
Defaults to `~/Downloads/images/logs` (or `OUTPUT_DIR/logs` when `OUTPUT_DIR` is set).
"""
from __future__ import annotations
import json
import logging
from datetime import datetime, timezone
from logging.handlers import RotatingFileHandler
from pathlib import Path
from typing import Any
from ..config.paths import get_log_directory
from ..config.settings import get_settings
_CONFIGURED = False
def _has_rotating_file_handler(logger: logging.Logger, file_path: Path) -> bool:
target = str(file_path)
for handler in logger.handlers:
if isinstance(handler, RotatingFileHandler) and getattr(handler, "baseFilename", "") == target:
return True
return False
def _has_console_handler(logger: logging.Logger) -> bool:
for handler in logger.handlers:
if isinstance(handler, logging.StreamHandler) and not isinstance(handler, logging.FileHandler):
return True
return False
def configure_logging() -> None:
"""Configure application logging (idempotent)."""
global _CONFIGURED
if _CONFIGURED:
return
settings = get_settings()
level_name = settings.log_level.upper()
level = getattr(logging, level_name, logging.INFO)
root_logger = logging.getLogger()
root_logger.setLevel(level)
human_formatter = logging.Formatter(
fmt="%(asctime)s %(levelname)s %(name)s: %(message)s",
datefmt="%Y-%m-%dT%H:%M:%S%z",
)
# Console logs (for MCP host capture)
if not _has_console_handler(root_logger):
stream_handler = logging.StreamHandler()
stream_handler.setLevel(level)
stream_handler.setFormatter(human_formatter)
root_logger.addHandler(stream_handler)
# File logs
try:
log_dir = get_log_directory()
log_file = log_dir / "imagen-mcp.log"
events_file = log_dir / "events.jsonl"
# Rotating file logs
if not _has_rotating_file_handler(root_logger, log_file):
file_handler = RotatingFileHandler(
log_file,
maxBytes=settings.log_max_bytes,
backupCount=settings.log_backup_count,
encoding="utf-8",
)
file_handler.setLevel(level)
file_handler.setFormatter(human_formatter)
root_logger.addHandler(file_handler)
# Structured JSONL events log (pure JSON per line)
events_logger = logging.getLogger("imagen_mcp.events")
events_logger.setLevel(level)
events_logger.propagate = False
if not _has_rotating_file_handler(events_logger, events_file):
events_handler = RotatingFileHandler(
events_file,
maxBytes=settings.log_max_bytes,
backupCount=settings.log_backup_count,
encoding="utf-8",
)
events_handler.setLevel(level)
events_handler.setFormatter(logging.Formatter("%(message)s"))
events_logger.addHandler(events_handler)
except Exception:
root_logger.exception("Failed to initialize file logging; continuing with console logging only")
_CONFIGURED = True
def log_event(event: str, **fields: Any) -> None:
"""Write a structured event to the JSONL events log."""
try:
configure_logging()
payload: dict[str, Any] = {
"timestamp": datetime.now(timezone.utc).isoformat(),
"event": event,
**fields,
}
logging.getLogger("imagen_mcp.events").info(
json.dumps(payload, ensure_ascii=False, default=str)
)
except Exception:
logging.getLogger(__name__).debug("Failed to write events log entry", exc_info=True)
