Glean MCP Server

import fs from 'fs'; import path from 'path'; import { ensureFileExistsWithLimitedPermissions, getStateDir as getXDGStateDir, } from '../xdg/xdg.js'; export enum LogLevel { TRACE = 0, DEBUG = 1, INFO = 2, WARN = 3, ERROR = 4, } /** * A simple logger that exposes functions for standard log levels (`trace, * `debug`, &c.) for a singleton logger. * * Logs are written to `$HOME/.local/state/glean/mcp.log` by default (or the * XDG equivalent for windows, or if XDG env vars are set). * * Logs are intended to be provided by users to help with troubleshooting. */ export class Logger { private static instance?: Logger; private logFilePath: string; private logLevel: LogLevel; constructor(appName = 'glean') { const logDir = getXDGStateDir(appName); // Ensure log directory exists if (!fs.existsSync(logDir)) { fs.mkdirSync(logDir, { recursive: true }); } this.logFilePath = path.join(logDir, 'mcp.log'); ensureFileExistsWithLimitedPermissions(this.logFilePath); this.logLevel = LogLevel.TRACE; // Default to most verbose logging } public static getInstance(): Logger { if (!Logger.instance) { Logger.instance = new Logger(); } return Logger.instance; } public static reset() { Logger.instance = undefined; } public setLogLevel(level: LogLevel): void { this.logLevel = level; } private log(level: LogLevel, ...args: any[]): void { if (level < this.logLevel) return; const timestamp = new Date().toISOString(); const levelName = LogLevel[level]; let message = ''; const dataObjects: Record<string, unknown>[] = []; // Helper to format errors with causes function formatErrorWithCauses(err: Error, indent = 0): string { const pad = ' '.repeat(indent); let out = `${pad}[${err.name}: ${err.message}]`; if (err.stack) { // Only include stack for the top-level error if (indent === 0) { out += `\n${pad}${err.stack.replace(/\n/g, `\n${pad}`)}`; } } // Handle error cause (ES2022 standard, but may be polyfilled) const cause = (err as any).cause; if (cause instanceof Error) { out += `\n${pad}Caused by: ` + formatErrorWithCauses(cause, indent + 1); } else if (cause !== undefined) { out += `\n${pad}Caused by: ${JSON.stringify(cause)}`; } return out; } // Process each argument args.forEach((arg) => { if (typeof arg === 'string') { message += (message ? ' ' : '') + arg; } else if (arg instanceof Error) { message += (message ? ' ' : '') + formatErrorWithCauses(arg); } else if (arg !== null && typeof arg === 'object') { dataObjects.push(arg); } else if (arg !== undefined) { // Convert primitives to string message += (message ? ' ' : '') + String(arg); } }); let logMessage = `[${timestamp}] [${levelName}] ${message}`; // Add data objects if any if (dataObjects.length > 0) { dataObjects.forEach((data) => { logMessage += ` ${JSON.stringify(data)}`; }); } logMessage += '\n'; // Append to log file fs.appendFileSync(this.logFilePath, logMessage); } public trace(...args: any[]): void { this.log(LogLevel.TRACE, ...args); } public debug(...args: any[]): void { this.log(LogLevel.DEBUG, ...args); } public info(...args: any[]): void { this.log(LogLevel.INFO, ...args); } public warn(...args: any[]): void { this.log(LogLevel.WARN, ...args); } public error(...args: any[]): void { this.log(LogLevel.ERROR, ...args); } } // Exported functions export function trace(...args: any[]): void { Logger.getInstance().trace(...args); } export function debug(...args: any[]): void { Logger.getInstance().debug(...args); } export function info(...args: any[]): void { Logger.getInstance().info(...args); } export function warn(...args: any[]): void { Logger.getInstance().warn(...args); } export function error(...args: any[]): void { Logger.getInstance().error(...args); }