Primus Logger

primus-logger is a tiny module for the Primus real-time framework that allows you to add context to logging messages.

Even if you're simply outputting data to the console, it is often useful to correlate certain messages with application context (for instance, to log which user was responsible for triggering a certain event). Such metadata usually resides on the Spark object, which this module can dynamically export by prefixing each message with certain object properties.

The modules wraps the winston logging library, which theoretically means that every option supported by winston is also supported by primus-logger (e.g. transport configuration).

Installation

Installation occurs via npm:

npm install primus-logger --save

Usage

Like any other Primus plugin, you only need to create a server instance and use the plugin. It exposes a new option, logging, where all the configuration necessary for the plugin can be defined.

By default, the Console transport of winston is used, which does not use colors or timestamps, with an info level output cut out. The following overrides theses defaults to adds colors and timestamps.

The prefix property uses an object path to get the data from the Spark instance. You can read more about how to formulate your prefix by visiting the object-path project page.

'use strict';

var Primus = require('primus'),
  winston = require('winston');

var server = http.createServer()
  , primus = new Primus(server, {
      logging: {
            prefix: ['id', 'address.ip'],
            transports: [
              new (winston.transports.Console)({
                'timestamp': true,
                'colorize': true
              })
            ]
          }
  });

primus.use('logger', 'primus-logger');

primus.on('connection', function (spark) {
  spark.info('Connected');

  if ('127.0.0.1' !== spark.address.ip) {
    spark.log('error', 'Unexpected ip "' + spark.address.ip + '"');
  }
});

The output on the console will look like this:

2014-01-01T15:00:28.012Z - info: [1388618721010$0/127.0.0.1] Connected
2014-01-01T15:00:28.012Z - error: [1388618721010$0/127.0.0.1] Unexpected ip "127.0.0.2"

Supported levels

The following logging levels are supported on a Spark instance:

• log (generic, requires a level argument)
• debug
• info
• warn
• error
• err (alias of error)

Options

Currently, the only configurable option on the primus-logger plugin, besides dynamic properties (configured as prefix), is the separator string (defaults to /).

Compatibility

This plugin has been tested against Primus 1.5.x only.

License

MIT