statsd-client

node-statsd-client

Node.js client for statsd.

Quick tour

var sdc = new require('statsd-client')({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});

Available options:

• host: Where to send the stats (default localhost).
• debug: Print what is being sent to stderr (default false).
• port: Port to contact the statsd-daemon on (default 8125).
• prefix: Prefix all stats with this value (default "").
• socket_timeout: Auto-closes the socket after this long without activity (default 1000 ms; 0 disables this).

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); // Indrement by 100

Gauges

Sends an arbitrary number to the back-end:

sdc.gauge('what.you.gauge', 100);

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, ...)

Stream helpers

There is some helpers for measuring what's going though streams:

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

var source = fs.createReadStream('some_file.txt'),
	dest = fs.createWriteStream('/dev/null');

// Option 1: Attach hooks directly to a stream (most effeicient)
sdc.helpers.streamSize('key_for_counter', source);

// Option 2: Pipe through proxy-stream with hooks attached
source
    .pipe(sdc.helpers.streamLatency('key_for_timer'))
	.pipe(dest);

This will both measure the amount of data sent through the system (.streamSize(key, [stream])) and how long it takes to get i through (.streamLatency(key, [stream])). It is also possible to measure the total bandwith of the stream using .streamBandwidth(key, [stream]).

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.

Stopping gracefully

By default, the socket is closed if it hasn't been used for a second (see socket_timeout 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.

Changelog

v0.0.11

• Release v0.0.11. (Morten Siebuhr)
• Allow custom URL-aliases in Express-middleware. (Morten Siebuhr)