The Complete Production SOP: How to Deploy and Run Winston Multi-Transport Logging & Daily File Rotation in Autonomous AI Agents

---
name: "winston-multi-transport-logger"
description: "Route logs to multiple outputs, format timestamps, and manage automated daily file rotation."
metadata:
  author: "Winston"
  version: "1.0.0"
  runtime_compatibility:
    - "codex"
    - "claude-code"
    - "cursor"
    - "windsurf"
triggers:
  - "configure winston logger"
  - "winston daily rotate file"
  - "custom winston format"
permissions:
  fs_read: true
  fs_write: "workspace"
  shell_exec: false
  net_access: false
---

import winston from 'winston';
import DailyRotateFile from 'winston-daily-rotate-file';
import path from 'path';

const LOG_DIR = process.env.LOG_DIR || path.join(process.cwd(), 'logs');

const consoleFormat = winston.format.combine(
  winston.format.colorize({ all: true }),
  winston.format.timestamp({ format: 'YYYY-MM-DD HH:mm:ss.SSS' }),
  winston.format.printf(({ timestamp, level, message, ...meta }) => {
    const metaString = Object.keys(meta).length ? JSON.stringify(meta, null, 2) : '';
    return `[${timestamp}] [${level}]: ${message} ${metaString}`;
  })
);

const fileFormat = winston.format.combine(
  winston.format.timestamp(),
  winston.format.errors({ stack: true }),
  winston.format.json()
);

export const logger = winston.createLogger({
  level: process.env.LOG_LEVEL || 'info',
  format: fileFormat,
  defaultMeta: { service: process.env.SERVICE_NAME || 'api-backend' },
  transports: [
    new winston.transports.Console({
      format: consoleFormat,
      silent: process.env.NODE_ENV === 'test',
    }),
    new DailyRotateFile({
      dirname: LOG_DIR,
      filename: 'application-%DATE%.log',
      datePattern: 'YYYY-MM-DD',
      zippedArchive: true,
      maxSize: '20m',
      maxFiles: '14d',
      level: 'info',
    }),
    new DailyRotateFile({
      dirname: LOG_DIR,
      filename: 'error-%DATE%.log',
      datePattern: 'YYYY-MM-DD',
      zippedArchive: true,
      maxSize: '20m',
      maxFiles: '30d',
      level: 'error',
    }),
  ],
  exceptionHandlers: [
    new DailyRotateFile({
      dirname: LOG_DIR,
      filename: 'exceptions-%DATE%.log',
      datePattern: 'YYYY-MM-DD',
      maxFiles: '30d',
    }),
  ],
  rejectionHandlers: [
    new DailyRotateFile({
      dirname: LOG_DIR,
      filename: 'rejections-%DATE%.log',
      datePattern: 'YYYY-MM-DD',
      maxFiles: '30d',
    }),
  ],
  exitOnError: false,
});

import { logger } from './utils/logger';

logger.info('HTTP server initializing', {
  port: process.env.PORT || 3000,
  nodeEnv: process.env.NODE_ENV || 'development',
});

#!/usr/bin/env bash
set -euo pipefail

echo 'Running logger lint and verification...'
npx eslint src/utils/logger.ts
npx tsc --noEmit

# Run smoke test in subshell
node -e "const { logger } = require('./dist/utils/logger'); logger.info('Healthcheck probe');"
if [ -d 'logs' ]; then
  echo 'Verification successful: logs directory created with active file transports.'
  exit 0
else
  echo 'Error: logs directory was not created.' >&2
  exit 1
fi