/**
* Shared logger utility
* IMPORTANT: For stdio transport, all logs must go to stderr (not stdout)
* stdout is reserved exclusively for JSON-RPC messages
*/
type LogLevel = 'ERROR' | 'INFO' | 'DEBUG';
/**
* Get current log level from environment
* Defaults to INFO
*/
function getLogLevel(): LogLevel {
const level = process.env.LOG_LEVEL?.toUpperCase();
if (level === 'ERROR' || level === 'INFO' || level === 'DEBUG') {
return level;
}
return 'INFO';
}
/**
* Check if a log level should be displayed
*/
function shouldLog(messageLevel: LogLevel): boolean {
const currentLevel = getLogLevel();
const levels: Record<LogLevel, number> = {
ERROR: 0,
INFO: 1,
DEBUG: 2,
};
return levels[messageLevel] <= levels[currentLevel];
}
/**
* Format log message
*/
function formatMessage(level: LogLevel, message: string): string {
const timestamp = new Date().toISOString();
return `[${level}] ${timestamp} - ${message}`;
}
export const log = {
error: (message: string, ...args: unknown[]): void => {
if (shouldLog('ERROR')) {
console.error(formatMessage('ERROR', message), ...args);
}
},
info: (message: string, ...args: unknown[]): void => {
if (shouldLog('INFO')) {
console.error(formatMessage('INFO', message), ...args);
}
},
debug: (message: string, ...args: unknown[]): void => {
if (shouldLog('DEBUG')) {
console.error(formatMessage('DEBUG', message), ...args);
}
},
};
