from collections.abc import Awaitable, Callable from typing import TypeAlias from mcp.client.session import LoggingFnT from mcp.types import LoggingMessageNotificationParams from fastmcp.utilities.logging import get_logger logger = get_logger(__name__) LogMessage: TypeAlias = LoggingMessageNotificationParams LogHandler: TypeAlias = Callable[[LogMessage], Awaitable[None]] async def default_log_handler(message: LogMessage) -> None: """Default handler that properly routes server log messages to appropriate log levels.""" msg = message.data.get("msg", str(message)) extra = message.data.get("extra", {}) # Map MCP log levels to Python logging levels level_map = { "debug": logger.debug, "info": logger.info, "notice": logger.info, # Python doesn't have 'notice', map to info "warning": logger.warning, "error": logger.error, "critical": logger.critical, "alert": logger.critical, # Map alert to critical "emergency": logger.critical, # Map emergency to critical } # Get the appropriate logging function based on the message level log_fn = level_map.get(message.level.lower(), logger.info) # Include logger name if available if message.logger: msg = f"[{message.logger}] {msg}" # Log with appropriate level and extra data log_fn(f"Server log: {msg}", extra=extra) def create_log_callback(handler: LogHandler | None = None) -> LoggingFnT: if handler is None: handler = default_log_handler async def log_callback(params: LoggingMessageNotificationParams) -> None: await handler(params) return log_callback