Metromatic NPM

metromatic

Report metrics based on events generated by a given event emitter. Supports StatsD, Cloudwatch & custom backends.

Installation

Install using npm

npm install metromatic

Usage

var Metromatic = require('metromatic');

const backends = [
  {
    type: 'statsd',
    host: 'localhost',
    port: 8125
  },
  {
    type: 'cloudwatch'
    region: 'us-west-1',
    groupName: 'MyService'
    dimensions: { environment: NODE_ENV },
    accessKeyId: AWS_CLOUDWATCH_KEY_ID,
    secretAccessKey: AWS_CLOUDWATCH_ACCESS_KEY,
  },
  {
    type: 'custom',
    send: (type, name, data) => {
      // handle metric storage
    },
  }
];

Metromatic.instrument(myEventEmitter, {
  backends: backends,
  metrics: [{
    name: 'request_time',
    type: 'timing', // timing or gauge currently supported
    eventStart: 'request',
    eventStop: 'response'
  }, {
    name: 'gauge_foo',
    type: 'gauge',
    eventGauge: 'hey'
  }]
});

Eventually, timings and gauges metrics will be sent when myEventEmitter emits the request and response events (for timing) or hey event (for gauge).

If you just want to stop listening the object:

Metromatic.restore(myEventEmitter);

To keep track of multiple timings of the same event pass any id string as a parameter when emitting the events to differentiate them.

Running tests

Run the tests using

npm test

Contributing

At the moment supports timing and gauges metric types. You're more than welcome to express some code love in a Pull Request to make it even more awesome.

Also, if you feel like something is quite not right or want to suggest something, leave us an open issue.