node-bunyan-lite/examples/raw-stream.js

// Example of a "raw" stream in a Bunyan Logger. A raw stream is one to
// which log record *objects* are written instead of the JSON-serialized
// string.

var Logger = require('../lib/bunyan');


/**
 * A raw Bunyan Logger stream object. It takes raw log records and writes
 * them to stdout with an added "yo": "yo" field.
 */
function MyRawStream() {}
MyRawStream.prototype.write = function (rec) {
  if (typeof (rec) !== 'object') {
    console.error('error: raw stream got a non-object record: %j', rec)
  } else {
    rec.yo = 'yo';
    process.stdout.write(JSON.stringify(rec) + '\n');
  }
}


// A Logger using the raw stream.
var log = new Logger({
  name: 'raw-example',
  streams: [
    {
      level: 'info',
      stream: new MyRawStream(),
      type: 'raw'
    },
  ]
});


log.info('hi raw stream');
log.info({foo: 'bar'}, 'added "foo" key');