A simple logger to dump applications logs into a dedicated Slack instance. It’s the poor person’s logging system, but it works!

slackLogger.js

const https = require('https');

function postToSlack(body) {
  return new Promise(function(ok, fail) {
    var jsonObject = JSON.stringify(body);

    // the post options
    var optionspost = {
      host: 'hooks.slack.com',
      port: 443,
      path: '<SLACK URL PATH HERE>',
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Content-Length': Buffer.byteLength(jsonObject, 'utf8')
      }
    };

    var req = https.request(optionspost, function (res) {

      var resp = '';

      res.on('data', function (d) {
        resp += d;
      });

      res.on('end', function() { ok(resp) });

    });

    req.on('error', fail);

    req.write(jsonObject);
    req.end();
  });
}

const TYPES = exports.TYPES = {
  SUCCESS: 'SUCCESS',
  ERROR: 'ERROR',
  WARNING: 'WARNING',
  INFO: 'INFO',
  ACCESS_LOG: 'ACCESS_LOG'
};

const ICONS = {
  SUCCESS: ':white_check_mark:',
  ERROR: ':fire:',
  WARNING: ':warning:',
  INFO: ':information_source:',
  ACCESS_LOG: ':scroll:'
};

const CHANNELS = {
  SUCCESS: 'logs',
  ERROR: 'errors',
  WARNING: 'errors',
  INFO: 'logs',
  ACCESS_LOG: 'access-logs'
};


function sendMessage({ message, type=TYPES.INFO, username, channel }) {

  const payload = {
    username: username || ('system_' + type).toLowerCase(),
    icon_emoji: ICONS[type] || ICONS.INFO,
    text: message,
    channel: '#' + (channel || CHANNELS[type])
  };

  return postToSlack(payload);
}

function log(message) {
  return sendMessage({ message });
}

function warn(message) {
  return sendMessage({ message, type: TYPES.WARNING });
}

function error(message) {
  return sendMessage({ message, type: TYPES.ERROR });
}


function accessLog(message) {
  return sendMessage({ message, type: TYPES.ACCESS_LOG });
}


module.exports = {
  TYPES,
  sendMessage,
  accessLog,
  log,
  warn,
  error
};