/**
* Debug logging utility for MCP server
* Logs to stderr (captured by Claude Desktop) and optionally to files
*/
import debugModule from 'debug';
import * as fs from 'node:fs';
import * as path from 'node:path';
import { fileURLToPath } from 'node:url';
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
// Create debug namespaces for different components
export const debugMain = debugModule('mcp:main');
export const debugServer = debugModule('mcp:server');
export const debugTransport = debugModule('mcp:transport');
export const debugTools = debugModule('mcp:tools');
export const debugData = debugModule('mcp:data');
export const debugHttp = debugModule('mcp:http');
export const debugSession = debugModule('mcp:session');
export const debugEnv = debugModule('mcp:env');
// Enable debug output based on environment variables
// Priority: DEBUG env var takes precedence, then DEBUG_MCHMCP for backward compatibility
if (process.env.DEBUG) {
// Use the standard debug module pattern
debugModule.enable(process.env.DEBUG);
} else if (process.env.DEBUG_MCHMCP === 'true') {
// Legacy compatibility - enable all mcp namespaces
debugModule.enable('mcp:*');
}
// File logging setup
// Use __dirname to get a path relative to the source file location
const PROJECT_ROOT = path.resolve(__dirname, '..', '..');
const LOG_DIR = path.join(PROJECT_ROOT, '.debug', 'logs');
let logStream: fs.WriteStream | null = null;
/**
* Initialize file logging if DEBUG_MCHMCP is enabled
*/
export function initFileLogging(clientName?: string): void {
if (process.env.DEBUG_MCHMCP !== 'true') {
return;
}
try {
// Create log directory if it doesn't exist (with parent directories)
fs.mkdirSync(LOG_DIR, { recursive: true });
// Generate log filename with timestamp
const timestamp = new Date().toISOString().replace(/[:.]/g, '-');
const clientPart = clientName ? `_${clientName.replace(/[^a-zA-Z0-9]/g, '-')}` : '';
const logFile = path.join(LOG_DIR, `mcp-server${clientPart}_${timestamp}.log`);
// Create write stream
logStream = fs.createWriteStream(logFile, { flags: 'a' });
// Override debug output to write to both stderr and file
const originalLog = debugModule.log;
debugModule.log = function (...args: unknown[]) {
// Write to stderr (default behavior)
originalLog.apply(debugModule, args);
// Also write to file
if (logStream && logStream.writable) {
const message = args.join(' ');
logStream.write(`${message}\n`);
}
};
debugMain(`Logging initialized to file: ${logFile}`);
} catch (error) {
console.error('Failed to initialize file logging:', error);
}
}
/**
* Close log file stream
*/
export function closeFileLogging(): void {
if (logStream) {
logStream.end();
logStream = null;
}
}
// Ensure logs are flushed on exit
process.on('exit', () => {
closeFileLogging();
});
