/**
* Logger utility that ensures all output goes to stderr
* This prevents corruption of stdout which is used for JSON-RPC messages
*/
type LogLevel = 'debug' | 'info' | 'warn' | 'error';
interface LogEntry {
timestamp: string;
level: LogLevel;
message: string;
data?: any;
}
class Logger {
private debugMode: boolean;
private serverName: string;
constructor(serverName: string = 'mav-postgresql-mcp') {
this.serverName = serverName;
this.debugMode = process.env.MCP_DEBUG?.toLowerCase() === 'true';
}
private formatMessage(level: LogLevel, message: string, data?: any): string {
const entry: LogEntry = {
timestamp: new Date().toISOString(),
level,
message,
data
};
return `[${entry.timestamp}] [${this.serverName}] [${level.toUpperCase()}] ${message}${
data ? ' ' + JSON.stringify(data) : ''
}`;
}
private log(level: LogLevel, message: string, data?: any): void {
const shouldLog = level !== 'debug' || this.debugMode;
if (shouldLog) {
// CRITICAL: Always use stderr, never stdout
console.error(this.formatMessage(level, message, data));
}
}
debug(message: string, data?: any): void {
this.log('debug', message, data);
}
info(message: string, data?: any): void {
this.log('info', message, data);
}
warn(message: string, data?: any): void {
this.log('warn', message, data);
}
error(message: string, error?: Error | any): void {
const errorData = error instanceof Error ? {
message: error.message,
stack: this.debugMode ? error.stack : undefined
} : error;
this.log('error', message, errorData);
}
// Special method for audit logging
audit(action: string, details: any): void {
const auditEntry = {
timestamp: new Date().toISOString(),
action,
details,
// Include request ID if available for tracing
requestId: (global as any).currentRequestId
};
// Always log audits regardless of debug mode
console.error(`[AUDIT] ${JSON.stringify(auditEntry)}`);
}
}
// Export singleton instance
export const logger = new Logger();
// Export class for testing or custom instances
export { Logger };
