Morgan and Winston examples

accessLogger.js

const { morgan, LOG_FORMAT } = require('./morgan');

const logFormat =
  !process.env.NODE_ENV || process.env.NODE_ENV === 'development'
    ? 'dev'
    : LOG_FORMAT;

module.exports = options =>
  morgan(logFormat, {
    skip(req, res) {
      return res.statusCode >= 400;
    },
    stream: process.stdout,
    ...options,
  });

errorLogger.js

const { morgan, LOG_FORMAT } = require('./morgan');

const logFormat =
  !process.env.NODE_ENV || process.env.NODE_ENV === 'development'
    ? 'dev'
    : LOG_FORMAT;

module.exports = options =>
  morgan(logFormat, {
    skip(req, res) {
      return res.statusCode < 400;
    },
    stream: process.stderr,
    ...options,
  });

logger.js

const { createLogger, format, transports } = require('winston');

const level = process.env.LOG_LEVEL || 'debug';
const { combine, timestamp, label, printf } = format;
const logFormat = printf(
  info => `${info.timestamp} [${info.label}] ${info.level}: ${info.message}`,
);

const logger = loggerLabel =>
  createLogger({
    level,
    format: combine(
      label({ label: loggerLabel || 'default' }),
      timestamp(),
      logFormat,
    ),
    transports: [new transports.Console()],
  });

module.exports = logger;

morgan.js

const morgan = require('morgan');

morgan.token('id', req => req.id);

// combined + req.id
const LOG_FORMAT =
  ':remote-addr - :remote-user [:date[clf]] [:id] ":method :url HTTP/:http-version" :status :res[content-length] ":referrer" ":user-agent"';

module.exports = { morgan, LOG_FORMAT };