kraken-feature-flagger
v1.0.5
Published
Feature Flags for Kraken
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kraken-feature-flagger
Feature flags for Kraken JS apps.
Install
Required: nodejs (tested against v0.10 and 0.12), or io.js (tested against v1.4.2), npm.
npm install kraken-feature-flagger --save
Usage
Configuration
In your config/config.json file, add a features section and some features. Set each feature to true or false to enable/disable:
{
"features": {
"happy": true,
"awesome": true,
"deprecated-feature": false
},
...
}App initialization
Create a kraken app as usual, and add the middleware to your app or an Express router/route.
var kraken = require('kraken-js'),
app = module.exports = require('express')(),
features = require('kraken-feature-flagger'),
options = {};
app.on('start', function () {
console.log('app started and ready to serve requests.');
});
app.use(kraken(options));
//set features flag middleware here,
//or in your routers
app.use(features());Routes
In a route, your enabled features will be available on req.features:
module.exports = function (router) {
router.get('/', function (req, res) {
console.log(req.features.enabled); // => ['happy', 'awesome']
if (req.features.has('awesome')) {
res.render('awesome');
} else {
res.render('sadtrombone');
}
});
}In views
You can set feature classes in your views as well, as res.locals.featureClasses is created for you:
<body class="{featureClasses}">...</body>returns
<body class="feature-happy feature-awesome">...</body>Route Gating
You can also "gate off" routes, which means that route is only available if your config enables it. Otherwise users will see a 503 Service Unavailable error. Here's an example:
var gate = require('kraken-feature-flagger/gate');
router.get('/gated', gate('awesome-people-only'), function (req, res) {
res.send('You must be awesome since they let you in here!');
});