mcp-use__mcp-use/libraries/python/mcp_use/server/logging/config.py

"""Configurable logging setup for MCP servers."""

import logging

from mcp_use.server.logging.formatters import ColoredFormatter, MCPAccessFormatter, MCPErrorFormatter


class InspectorLogFilter(logging.Filter):
    """Filter that hides inspector-related access logs."""

    def __init__(self, inspector_path: str = "/inspector"):
        super().__init__()
        self.inspector_path = inspector_path

    def filter(self, record: logging.LogRecord) -> bool:
        # Check if args contain a path that starts with inspector_path
        args = record.args
        if args is not None and isinstance(args, tuple) and len(args) >= 3:
            path = args[2]
            if isinstance(path, str) and self.inspector_path in path:
                return False
        return True


class MCPLogsOnlyFilter(logging.Filter):
    """Filter that drops all uvicorn access log records.

    MCP protocol logs are printed directly to stdout by MCPLoggingMiddleware,
    bypassing the logging system entirely. This filter drops all uvicorn access
    records so only the MCP: lines remain.
    """

    def filter(self, record: logging.LogRecord) -> bool:
        args = record.args
        if args is not None and isinstance(args, tuple) and len(args) >= 3:
            return False
        return True


def setup_logging(
    debug_level: int = 0,
    log_level: str = "INFO",
    show_inspector_logs: bool = False,
    inspector_path: str = "/inspector",
    mcp_logs_only: bool = False,
) -> dict:
    """Set up logging configuration for MCP server.

    Args:
        debug_level: Debug level (0: production, 1: debug+routes, 2: debug+routes+jsonrpc)
        log_level: Logging level (DEBUG, INFO, WARNING, ERROR)
        show_inspector_logs: Whether to show inspector-related access logs (default: False)
        inspector_path: Effective inspector route prefix, typically `/inspector`
            or a prefixed route like `/mcp/inspector`
        mcp_logs_only: When True, suppress all uvicorn access logs (MCP logs are printed
            directly by the middleware). Default: False.

    Returns:
        Uvicorn logging configuration dict
    """

    # Suppress noisy loggers
    suppressed_loggers = {
        "uvicorn.error": "ERROR",
        "mcp.server.lowlevel.server": "CRITICAL",
        "mcp.server.streamable_http_manager": "CRITICAL",
        "mcp.server.fastmcp": "CRITICAL",
        "mcp": "CRITICAL",
        "httpx": "WARNING",
    }

    # Configure loggers
    loggers = {
        # Access logs with MCP enhancement (handled by middleware)
        "uvicorn.access": {"handlers": ["access"], "level": log_level, "propagate": False},
        # Error logs with custom formatting
        "uvicorn.error": {"handlers": ["error"], "level": "ERROR", "propagate": False},
        # Suppress noisy loggers
        **{
            logger_name: {"handlers": ["null"], "level": level, "propagate": False}
            for logger_name, level in suppressed_loggers.items()
            if logger_name != "uvicorn.error"
        },
    }

    # Add debug logger if debug mode is enabled
    if debug_level >= 2:
        loggers["mcp.debug"] = {"handlers": ["debug"], "level": "DEBUG", "propagate": False}

    # Build filters
    filters = {}
    if not show_inspector_logs:
        filters["inspector_filter"] = {"()": InspectorLogFilter, "inspector_path": inspector_path}
    if mcp_logs_only:
        filters["mcp_logs_only_filter"] = {"()": MCPLogsOnlyFilter}

    # Build access handler with optional filters
    access_filters = []
    if not show_inspector_logs:
        access_filters.append("inspector_filter")
    if mcp_logs_only:
        access_filters.append("mcp_logs_only_filter")
    access_handler = {
        "formatter": "access",
        "class": "logging.StreamHandler",
        "stream": "ext://sys.stdout",
    }
    if access_filters:
        access_handler["filters"] = access_filters

    return {
        "version": 1,
        "disable_existing_loggers": False,
        "filters": filters,
        "formatters": {
            "access": {
                "()": MCPAccessFormatter,
            },
            "error": {
                "()": MCPErrorFormatter,
            },
            "debug": {
                "fmt": "%(levelname)s: %(message)s",
            },
            "colored": {
                "()": ColoredFormatter,
                "fmt": "%(levelname)-8s %(name)s: %(message)s",
            },
        },
        "handlers": {
            "access": access_handler,
            "error": {
                "formatter": "error",
                "class": "logging.StreamHandler",
                "stream": "ext://sys.stderr",
            },
            "debug": {
                "formatter": "colored" if debug_level >= 2 else "debug",
                "class": "logging.StreamHandler",
                "stream": "ext://sys.stdout",
            },
            "null": {
                "class": "logging.NullHandler",
            },
        },
        "loggers": loggers,
    }