import { config } from '../config.js';
/**
* Log levels
*/
export type LogLevel = 'debug' | 'info' | 'warn' | 'error';
/**
* Log level priority (higher = more severe)
*/
const LOG_LEVELS: Record<LogLevel, number> = {
debug: 0,
info: 1,
warn: 2,
error: 3,
};
/**
* Log entry structure
*/
interface LogEntry {
timestamp: string;
level: LogLevel;
message: string;
data?: Record<string, unknown>;
}
/**
* Keys that should be redacted from logs
*/
const SENSITIVE_KEYS = [
'password',
'secret',
'token',
'key',
'credential',
'auth',
'apikey',
'api_key',
];
/**
* Sanitize data by removing sensitive information
*/
function sanitizeData(data: Record<string, unknown>): Record<string, unknown> {
const sanitized: Record<string, unknown> = {};
for (const [key, value] of Object.entries(data)) {
const lowerKey = key.toLowerCase();
// Check if key contains sensitive words
if (SENSITIVE_KEYS.some((sk) => lowerKey.includes(sk))) {
sanitized[key] = '***REDACTED***';
} else if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
// Recursively sanitize nested objects
sanitized[key] = sanitizeData(value as Record<string, unknown>);
} else {
sanitized[key] = value;
}
}
return sanitized;
}
/**
* Log a message with optional data
*
* IMPORTANT: Uses console.error to avoid interfering with stdio transport
*/
export function log(
level: LogLevel,
message: string,
data?: Record<string, unknown>
): void {
// Check if we should log based on configured level
if (LOG_LEVELS[level] < LOG_LEVELS[config.LOG_LEVEL]) {
return;
}
const entry: LogEntry = {
timestamp: new Date().toISOString(),
level,
message,
};
// Add sanitized data if provided
if (data) {
entry.data = sanitizeData(data);
}
// Output to stderr (NEVER stdout - it's used for MCP protocol)
console.error(JSON.stringify(entry));
}
/**
* Convenience methods for each log level
*/
export const logger = {
debug: (message: string, data?: Record<string, unknown>) => log('debug', message, data),
info: (message: string, data?: Record<string, unknown>) => log('info', message, data),
warn: (message: string, data?: Record<string, unknown>) => log('warn', message, data),
error: (message: string, data?: Record<string, unknown>) => log('error', message, data),
};
