Feature Flags In Laravel

Overview
Installing
Usage
Usage Non Auth
Example
Testing
Todo

Overview

You can find a comprehensive blog post about this library here. This project is a work in progress.

We are working on using FeatureFlags or Toggles in our applications. For one we are aiming to do all our work on mainline branch at all times so this would be a key coding discipline to use FeatureFlags so we can hide a feature in progress knowing it will not interfere with the application. For example if a hotfix or another feature is ready to go to production we can push that with no worries of the in progress feature.

At the core we use this library Atriedes/feature as it has the logic needed to consider common feature flag states eg user, users, on, off, groups, admin, internal, random etc. However, we are also mixing in some nice Laravel Authorizationfeatures so you can do things like:

In a blade template:

@can('feature-flag', 'add-twitter-field')
<!-- code here -->
@endcan

Or in PHP:

if (Gate::allows('feature-flag', 'awesome-feature')) {
    <!-- code here -->
}

if (Gate::denies('feature-flag', 'awesome-feature')) {
    <!-- code here -->
}

If you need to pass your feature flags to a front-end JS framework like Angular or Vue.js, you can do so by using the FeatureFlagsForJavascript::get() static method:

$js->put(
            [
                'pusher_public_key' => env('PUSHER_PUBLIC'),
                'feature_flags'     => FeatureFlagsForJavascript::get()
            ]
        );

Installing

Set your composer.json to the following to avoid composer error messages:

"config": {
        ....
    },
    "minimum-stability": "dev"
}

Require the package using composer:

composer require alfred-nutile-inc/laravel-feature-flag

Add the following to your config/app.php providers array:

AlfredNutileInc\LaravelFeatureFlags\FeatureFlagsProvider::class,

Publish the package migrations:

php artisan vendor:publish --provider="AlfredNutileInc\LaravelFeatureFlags\FeatureFlagsProvider" --tag='migrations'

Then run migration to setup the base table:

php artisan migrate

This package creates a number of routes. They can be overridden by publishing the views:

php artisan vendor:publish --provider="AlfredNutileInc\LaravelFeatureFlags\FeatureFlagsProvider" --tag='views'

This will then place the files in resources/vendors/laravel-feature-flags. Just note that the views @extends('layouts.default') so if yours differs you will need to make an adjustment to the published views files.

Next, publish the configuration:

php artisan vendor:publish --provider="AlfredNutileInc\LaravelFeatureFlags\FeatureFlagsProvider" --tag='config'

Important: The routes detault to being projected by the 'auth' middleware but you should check your installation to make sure permissions are acceptable. Middleware settings are configurable in 'config/laravel-feature-flag.php' file.

Usage

Visit /admin/feature_flags to manage features via the UI.

Usage Non Auth

Sometimes you are not using this at the Auth user level, it is rare for most of our use cases but for non authenticated situations you can just use this

if(\Feature\Feature::isEnabled('see-twitter-field'))
{
  //do something
}

You can see more about that class here vendor/jowy/feature/src/Feature/Feature.php

Remember you needed to put this into the database, so it is on or off. You might not have a UI, maybe this is a microservice for example, so just migrate the state into the database for example

$feature = new FeatureFlag();
$feature->key = "see-twitter-field";
$feature->variants = "on"; //or "off"
$feature->save();

Now when the FeatureFlag Provider instantiates it will set this as the "World" state and you can access it via the isEnabled "on" being true and "off" being false.

Demo / Example

If you want to try the demo/example also include the following in your config/app.php providers array:

AlfredNutileInc\LaravelFeatureFlags\ExampleFeatureProvider::class

and then run:

php artisan vendor:publish --provider="AlfredNutileInc\LaravelFeatureFlags\ExampleFeatureProvider" --tag='migrations'
php artisan migrate

It has a rollback to help clean up after.

There is a dummy route called /admin/feature_flags/example that you can visit and it will show that it is not on. But if you then go to the admin UI /admin/feature_flags you can toggle it on and off.

Testing

This Library pulls in jowy/feature and that library has tests. Other than that the there is the settings page which I do have some Laravel tests for that you can run once the package is installed.

Also if you are trying to test the use of it in your work you can use the helper trait in your test class

    use DatabaseTransactions, \AlfredNutileInc\LaravelFeatureFlags\FeatureFlagHelper;

Then from there factory out your additions and state then reregister the world

    /**
     * @test
     */
    public function should_fail_validation_since_twitter_missing()
    {
        //Make a form request
        //Set validation on that related to twitter field
        //make sure the feature flag is on

        $user_id = Rhumsaa\Uuid\Uuid::uuid4()->toString();

        $user = factory(\App\User::class)->create([
            'id' => $user_id,
            'is_admin' => 1
        ]);

        $this->actingAs($user);

        factory(\AlfredNutileInc\LaravelFeatureFlags\FeatureFlag::class)->create(
            [
                'key' => 'add-twitter-field',
                'variants' => 'on'
            ]
        );

        $this->registerFeatureFlags();
        ////
    }

TODO

Use Model Events to do that level of work
Cache of the FeatureFlag Settings and update Cache on Change
Show how it works in the menu and other areas eg include and Provider

iamlucianojr / laravel-feature-flag