egg-logger

Egg logger.

diagram

Including two base class, Logger and Transport:

Transport: Save log to file, stdout/stderr and network.
Logger: A logger can contains multi transports.

Install

$ npm i egg-logger

Usage

Create a Logger and add a file Transport.

const Logger = require('egg-logger').Logger;
const FileTransport = require('egg-logger').FileTransport;
const ConsoleTransport = require('egg-logger').ConsoleTransport;

const logger = new Logger();
logger.set('file', new FileTransport({
  file: '/path/to/file',
  level: 'INFO',
}));
logger.set('console', new ConsoleTransport({
  level: 'DEBUG',
}));
logger.debug('debug foo'); // only output to stdout
logger.info('info foo');
logger.warn('warn foo');
logger.error(new Error('error foo'));

Enable / Disable Transport

logger.disable('file');
logger.info('info'); // output nothing
logger.enable('file');
logger.info('info'); // output 'info' string

Duplicate

Duplicate error log to other logger.

Accept an options.excludes to special whether excludes some tranports.

logger.duplicate('error', errorLogger, { excludes: [ 'console' ]});
logger.error(new Error('print to errorLogger')); // will additional call `errorLogger.error`

Redirect

Redirect special level log to other logger.

oneLogger.redirect('debug', debugLogger); // all debug level logs of `oneLogger` will delegate to debugLogger

Reload

logger.reload(); // will close the exists write stream and create a new one.

Custom Transport

You can make your own Transport for logging，e.g.: send log to your logging server.

const urllib = require('urllib');
const Transport = require('egg-logger').Transport;

class UrllibTransport extends Transport {

  log(level, args, meta) {
    const msg = super.log(level, args, meta);
    return urllib.request('url?msg=' + msg);
  }
}

const logger = new Logger();
logger.set('remote', new UrllibTransport({
  level: 'DEBUG',
}));
logger.info('info');