logger.ts•1.22 kB
import { pino, Logger } from 'pino'; // Try named import for the function
/**
* Pino logger instance configured for structured JSON logging to stderr.
* MCP servers typically use stdout for protocol messages, so logs go to stderr.
*/
export const logger: Logger = pino(
{
level: process.env.LOG_LEVEL || 'info', // Default to 'info', configurable via env var
formatters: {
level: (label: string) => { // Add type for label
// Standardize level labels if desired, e.g., uppercase
return { level: label.toUpperCase() };
},
// bindings: (bindings) => {
// // Add custom bindings if needed, e.g., hostname, pid
// return { pid: bindings.pid, hostname: bindings.hostname };
// },
},
timestamp: pino.stdTimeFunctions.isoTime, // Use ISO 8601 timestamps
},
pino.destination(2) // Direct output to stderr (file descriptor 2)
);
// Example usage (replace console.log/error calls throughout the app):
// logger.info('Server starting...');
// logger.debug({ userId: '123' }, 'User logged in');
// logger.error(new Error('Something failed'), 'Failed to process request');