pn-logging

A logging wrapper around winston and sentry.

Usage

Ad-hoc log message

var Log = require('pn-logging').Log;

var logger = new Log(config);

// Call methods
logger.info('Message', meta);

logger.error('Error message', err);
// or
logger.error('Error message', meta, err);

Request/response middleware

// Use Express middleware
app.use(logger.middleware());

app.get('/', (req, res, next) => {
  // ...
  res.locals._log.addMeta({ keyName: 'value' });
  // ...
})

The big picture idea is that every req/res gets one log message, the level of which is set according to the final response status code:

• 200s = info
• 400s = warning (usually)
• 500s = error

The middleware attaches a log object to every req/res lifecycle as res.locals_log. This object exposes methods like addMeta and addError that attach fields to the final log for that req/res cycle.

addMeta attaches useful and relevant info about that req/res cycle as k/v pairs on its meta property. addError is a helper method that takes an Error, extracts useful info from it, and attaches it to meta.

(Errors within a req/res lifecycle may also warrant their own ad-hoc log messages, such as if an API request to a service fails.)

Config

The config object passed to Log constructor should look like:

var config = {
  transports: [
    {
      Console: {
        level: 'info',
        json: true,
        prettyPrint: true,
        silent: true // for test
      }
    },
    {
      Loggly: {
        level: 'warning',
        json: true,
        tag: 'APP_NAME',
        subdomain: process.env.LOGGLY_SUBDOMAIN,
        token: process.env.LOGGLY_TOKEN
      }
    }
  ],
};