pn-logging

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.)

Report to Sentry

If error object is passed to logger's logging methods, e.g. error, in addition to sending data to defined transporter (most likely Loggly), the error will also be sent to Sentry.

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

logger.error('Error message', {
  tags: {key: 'value'}
}, err);

Refer to sentry docs.

tags, fingerprint, and level properties of log meta object will be mapped to related sentry optional attributes. All other meta properties will become extra property in sentry optional attributes.

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
      }
    }
  ],
  sentry: {
    // specify `false` here to disable sentry
    dsn: 'https://*****@app.getsentry.com/xxxxx',
    // pass directly to raven constructor refer to https://goo.gl/9Ud7Mz
    options: {}
  }
};