node-statsd-client

Node.js client for statsd.

Quick tour

var SDC = require('statsd-client'),
	sdc = new SDC({host: 'statsd.example.com'});

var timer = new Date();
sdc.increment('some.counter'); // Increment by one.
sdc.gauge('some.gauge', 10); // Set gauge to 10
sdc.timing('some.timer', timer); // Calculates time diff

sdc.close(); // Optional - stop NOW

API

Initialization

var SDC = require('statsd-client'),
	sdc = new SDC({host: 'statsd.example.com', port: 8124, debug: true});

Global options:

• prefix: Prefix all stats with this value (default "").
• debug: Print what is being sent to stderr (default false).
• tcp: User specifically wants to use tcp (default false).
• socketTimeout: Dual-use timer. Will flush metrics every interval. For UDP, it auto-closes the socket after this long without activity (default 1000 ms; 0 disables this). For TCP, it auto-closes the socket after socketTimeoutsToClose number of timeouts have elapsed without activity.

UDP options:

• host: Where to send the stats (default localhost).
• port: Port to contact the statsd-daemon on (default 8125).

TCP options:

• host: Where to send the stats (default localhost).
• port: Port to contact the statsd-daemon on (default 8125).
• socketTimeoutsToClose: Number of timeouts in which the socket auto-closes if it has been inactive. (default 10; 1 to auto-close after a single timeout).

HTTP options:

• host: The URL to send metrics to (default: http://localhost).
• headers: Additional headers to send (default {})
• method: What HTTP method to use (default PUT)

Counting stuff

Counters are supported, both as raw .counter(metric, delta) and with the shortcuts .increment(metric, [delta=1]) and .decrement(metric, [delta=-1]):

sdc.increment('systemname.subsystem.value'); // Increment by one
sdc.decrement('systemname.subsystem.value', -10); // Decrement by 10
sdc.counter('systemname.subsystem.value', 100); // Increment by 100

Gauges

Sends an arbitrary number to the back-end:

sdc.gauge('what.you.gauge', 100);
sdc.gaugeDelta('what.you.gauge', 20);  // Will now count 120
sdc.gaugeDelta('what.you.gauge', -70); // Will now count 50
sdc.gauge('what.you.gauge', 10);       // Will now count 10

Sets

Send unique occurences of events between flushes to the back-end:

sdc.set('your.set', 200);

Delays

Keep track of how fast (or slow) your stuff is:

var start = new Date();
setTimeout(function () {
	sdc.timing('random.timeout', start);
}, 100 * Math.random());

If it is given a Date, it will calculate the difference, and anything else will be passed straight through.

And don't let the name (or nifty interface) fool you - it can measure any kind of number, where you want to see the distribution (content lengths, list items, query sizes, ...)

Express helper

There's also a helper for measuring stuff in Express.js via middleware:

var app = express();
	sdc = new StatsDClient({...});

app.use(sdc.helpers.getExpressMiddleware('somePrefix'));
// or
app.get('/',
	sdc.helpers.getExpressMiddleware('otherPrefix'),
	function (req, res, next) { req.pipe(res); });

app.listen(3000);

This will count responses by status-code (prefix.<statuscode>) and the overall response-times.

It can also measure per-URL (e.g. PUT to /:user/:thing will become PUT_user_thing by setting the timeByUrl: true in the options-object:

app.use(sdc.helpers.getExpressMiddleware('prefix', { timeByUrl: true }));

As the names can become rather odd in corner-cases (esp. regexes and non-REST interfaces), you can specify another value by setting res.locals.statsdUrlKey at a later point.

Stopping gracefully

By default, the socket is closed if it hasn't been used for a second (see socketTimeout in the init-options), but it can also be force-closed with .close():

var start = new Date();
setTimeout(function () {
	sdc.timing('random.timeout', start); // 2 - implicitly re-creates socket.
	sdc.close(); // 3 - Closes socket after last use.
}, 100 * Math.random());
sdc.close(); // 1 - Closes socket early.

The call is idempotent, so you can call it "just to be sure". And if you submit new metrics later, the socket will automatically be re-created, and a new timeout-timer started.

Prefix-magic

The library supports getting "child" clients with extra prefixes, to help with making sane name-spacing in apps:

// Create generic client
var sdc = new StatsDClient({host: 'statsd.example.com', prefix: 'systemname'});
sdc.increment('foo'); // Increments 'systemname.foo'
... do great stuff ...

// Subsystem A
var sdcA = sdc.getChildClient('a');
sdcA.increment('foo'); // Increments 'systemname.a.foo'

// Subsystem B
var sdcB = sdc.getChildClient('b');
sdcB.increment('foo'); // Increments 'systemname.b.foo'

Internally, they all use the same socket, so calling .close() on any of them will allow the entire program to stop gracefully.

What's broken

Check the GitHub issues.

LICENSE

ISC - see LICENSE.