busybody

Your friendly neighborhood request tracker?

Example

Setup

import express from 'express';
import busybody from 'busybody';

const app = express();
const tracker = busybody();

app.use(tracker);

app.get('/stats', (req, res) => {
  res.send(tracker.getStats(req.query.sortBy));
});

app.get('/ping', (req, res) => {
  setTimeout(() => res.send('pong'), 100);
});

app.listen(8080, () => console.log('Server listening'));

Output

{
  "since": "2016-05-19T21:18:44.362Z",
  "routes": [
    {
      "route": "/ping",
      "count": 4,
      "mean": 127.5,
      "standardDeviation": 25.5,
      "min": 96.3,
      "max": 153.4
    },
    {
      "route": "/stats",
      "count": 4,
      "mean": 1.7,
      "standardDeviation": 1.1,
      "min": 1,
      "max": 3.5
    }
  ]
}

API

busybody(options) -> tracker

Creates a new tracker. Takes in the following options.

• step=21600000 - Time between steps in milliseconds. Defaults to 6 hours.
• window = 4 - Maximum steps to store.
• maxSize = 500 - Maximum unique paths to store per step, after path sanitization.
• precision = 2 - Maximum decimals to round to.
• preFilter(req, res) -> boolean - Custom function to filter tracked requests before they're handled.
• postFilter(err, req, res) -> boolean - Custom function to filter tracked requests after they're handled.
• sanitize(req, res) -> string - Custom function to sanitize a url. By default, removes querystring, ids, uuids, and casing.
• onStep(step) - shortcut for tracker.on('step', fn) (see Events)
• onExpire(step) - shortcut for tracker.on('expire', fn) (see Events)

busybody.sanitize(req, res) -> string

The default sanitization function. It makes the following transformations to req.originalUrl.

1. Extract the pathname.
2. Normalize the pathname.
3. Replace all numbers with :id.
4. Replace all uuids with :uuid.
5. Make everything lowercase.

Example

> /path/../2/something?foo=bar
/:id/something/

> /foo/BAR/21/123e4567-e89b-12d3-a456-426655440000
/foo/bar/:id/:uuid/

tracker(req, res, next)

Express middleware that should be placed above routes you want to keep stats about.

tracker.getStats(sort = 'mean') -> object

Returns the stats output.

The sort parameter can be count, mean, standardDeviation, min, or max.

tracker.push(path, ms)

Manually track a path and duration.

Events

The middleware returned by busybody is also an EventEmitter that exposes the following events:

• expire - emitted when a step is about to expire. Passed the expiring step.
• step - emitted after a new step was created. Passed the new step.