logger.ts•1.96 kB
export enum LogLevel {
OFF = -1,
ERROR = 0,
WARN = 1,
INFO = 2,
DEBUG = 3,
}
export class Logger {
private level: LogLevel;
private name: string;
constructor(name: string, level: LogLevel = LogLevel.ERROR) {
this.name = name;
this.level = level;
}
private log(level: LogLevel, message: string, ...args: any[]): void {
if (level > this.level) return;
const timestamp = new Date().toISOString();
const levelName = LogLevel[level];
const prefix = `[${timestamp}] [${levelName}] [${this.name}]`;
// For MCP servers, all logs should go to stderr to avoid
// interfering with the JSON-RPC communication on stdout
console.error(prefix, message, ...args);
// Force flush in non-TTY environments (like CI)
if (!process.stderr.isTTY && process.stderr.write) {
process.stderr.write('');
}
}
error(message: string, ...args: any[]): void {
this.log(LogLevel.ERROR, message, ...args);
}
warn(message: string, ...args: any[]): void {
this.log(LogLevel.WARN, message, ...args);
}
info(message: string, ...args: any[]): void {
this.log(LogLevel.INFO, message, ...args);
}
debug(message: string, ...args: any[]): void {
this.log(LogLevel.DEBUG, message, ...args);
}
setLevel(level: LogLevel): void {
this.level = level;
}
}
// Global logger instance
export const logger = new Logger('MCP');
// Set log level from environment
const envLevel = process.env.LOG_LEVEL?.toUpperCase();
if (envLevel) {
if (envLevel === 'OFF') {
logger.setLevel(LogLevel.OFF);
} else if (envLevel in LogLevel) {
logger.setLevel(
LogLevel[envLevel as keyof typeof LogLevel] as unknown as LogLevel
);
}
} else {
// Default to OFF for MCP servers to avoid any debug output
logger.setLevel(LogLevel.OFF);
}