mcp-use/dist/src/logging.js

A utility library for integrating Model Context Protocol (MCP) with LangChain, Zod, and related tools. Provides helpers for schema conversion, event streaming, and SDK usage.

import fs from 'node:fs';
import path from 'node:path';
import { createLogger, format, transports } from 'winston';
const { combine, timestamp, label, printf, colorize, splat } = format;
const DEFAULT_LOGGER_NAME = 'mcp-use';
function resolveLevel(env) {
    switch (env?.trim()) {
        case '2':
            return 'debug';
        case '1':
            return 'info';
        default:
            return 'info';
    }
}
const minimalFormatter = printf(({ level, message, label, timestamp }) => {
    return `${timestamp} [${label}] ${level}: ${message}`;
});
const detailedFormatter = printf(({ level, message, label, timestamp }) => {
    return `${timestamp} [${label}] ${level.toUpperCase()}: ${message}`;
});
const emojiFormatter = printf(({ level, message, label, timestamp }) => {
    return `${timestamp} [${label}] ${level.toUpperCase()}: ${message}`;
});
export class Logger {
    static instances = {};
    static currentFormat = 'minimal';
    static get(name = DEFAULT_LOGGER_NAME) {
        if (!this.instances[name]) {
            this.instances[name] = createLogger({
                level: resolveLevel(process.env.DEBUG),
                format: combine(colorize(), splat(), label({ label: name }), timestamp({ format: 'HH:mm:ss' }), this.getFormatter()),
                transports: [],
            });
        }
        return this.instances[name];
    }
    static getFormatter() {
        switch (this.currentFormat) {
            case 'minimal':
                return minimalFormatter;
            case 'detailed':
                return detailedFormatter;
            case 'emoji':
                return emojiFormatter;
            default:
                return minimalFormatter;
        }
    }
    static configure(options = {}) {
        const { level, console = true, file, format = 'minimal' } = options;
        const resolvedLevel = level ?? resolveLevel(process.env.DEBUG);
        this.currentFormat = format;
        const root = this.get();
        root.level = resolvedLevel;
        root.clear();
        if (console) {
            root.add(new transports.Console());
        }
        if (file) {
            const dir = path.dirname(path.resolve(file));
            if (!fs.existsSync(dir)) {
                fs.mkdirSync(dir, { recursive: true });
            }
            root.add(new transports.File({ filename: file }));
        }
        // Update all existing loggers with new format
        Object.values(this.instances).forEach((logger) => {
            logger.level = resolvedLevel;
            logger.format = combine(colorize(), splat(), label({ label: DEFAULT_LOGGER_NAME }), timestamp({ format: 'HH:mm:ss' }), this.getFormatter());
        });
    }
    static setDebug(enabled) {
        let level;
        if (enabled === 2 || enabled === true)
            level = 'debug';
        else if (enabled === 1)
            level = 'info';
        else
            level = 'info';
        Object.values(this.instances).forEach((logger) => {
            logger.level = level;
        });
        process.env.DEBUG = enabled ? (enabled === true ? '2' : String(enabled)) : '0';
    }
    static setFormat(format) {
        this.currentFormat = format;
        this.configure({ format });
    }
}
Logger.configure();
export const logger = Logger.get();