Feature Toggles

A simple feature toggle api for Laravel applications.

Table of Contents

• Installation
• Testing
• Usage
  • Toggle Booting
  • Helper Functions
  • Use with Laravel Blade Custom Directive
  • Use with Laravel Middleware
  • Use with Laravel Task Scheduling
  • Use with Laravel Validation
    • Simple String
    • Via Illuminate\Validation\Rule
    • requiredIfRule Method on FeatureToggleApi
• Toggle Providers
  • Add Additional Toggle Providers
  • Local Feature Toggles
    • Toggle Parsing
  • Conditional Feature Toggles
  • Eloquent Feature Toggles
    • Database Migration
    • Eloquent Model
  • QueryString Toggle Provider
    • Configure Query String Keys
    • Add Api Key Authorization
  • Redis Toggle Provider
  • Session Toggle Provider
• Frontend Feature Toggle Api
• Road Map

Installation

Install using composer by running:

composer require ericdowell/feature-toggle ^1.11

Publish the feature-toggle.php config file by running:

php artisan vendor:publish --tag="feature-toggle-config"

Testing

Run composer test.

Usage

If a feature toggle is not defined then isActive will return false.

Toggle Booting

The Feature Toggle Api will pull all possible toggles at the boot of the application. This design allows there to be one database/cache/redis query instead of possibly many calls. This only becomes a problem if there're 100s of feature toggles.

Be mindful of how many database toggles are setup at given time, instead setup or move toggles to the local provider in config/feature-toggle.php.

Helper Functions

feature_toggle_api:

if (feature_toggle_api()->isActive('Example')) {
    // do something
}

Or a shorter function that does the same as above called feature_toggle:

if (feature_toggle('Example')) {
    // do something
}

The feature_toggle function also allows a second parameter to be passed to allow for checking if the toggle is active (true) or if it is inactive (false):

if (feature_toggle('Example', false)) {
    // do something when toggle is inactive
}
// OR
if (feature_toggle('Example', 'off')) {
    // do something when toggle is inactive
}

The second parameter will parse as the local toggle does, read more in the Toggle Parsing section to learn more.

Use with Laravel Blade Custom Directive

This custom directive uses the feature_toggle helper function directly, you can expect the same behavior:

@featureToggle('Example')
    // do something
@endfeatureToggle

Or if you'd like to check if the Example is inactive then you may pass a falsy value as the second parameter:

// returns true if toggle is inactive
@featureToggle('Example', false)
    // do something
@endfeatureToggle
// OR
@featureToggle('Example', 'off')
    // do something
@endfeatureToggle

Or you can use the normal @if blade directive and call feature_toggle function directly:

@if(feature_toggle('Example'))
    // do something
@endif
// OR
@if(feature_toggle('Example', 'off'))
    // do something
@endif

Use with Laravel Middleware

The middleware signature is as follows:

featureToggle:{name},{status},{abort}

Where status and abort are optional parameters. status will default to true (truthy) and abort will default to 404 status code. name is required.

Examples:

use Illuminate\Support\Facades\Route;

// Passing all three parameters, changing abort to 403 status code.
Route::get('user/billing')->middleware('featureToggle:subscription,true,403')->uses('User\\BillingController@index')->name('billing.index');
// Passing two parameters.
Route::get('user/subscribe')->middleware('featureToggle:subscription,true')->uses('User\\SubscribeController@index')->name('subscribe.index');
// Passing just the name.
Route::get('user/trial')->middleware('featureToggle:trial')->uses('User\\TrialController@index')->name('trial.index');

Use with Laravel Task Scheduling

You can use the built-in when function in combination with the feature_toggle helper function in the app/Console/Kernel.php schedule method.

use Illuminate\Console\Scheduling\Schedule;
use Illuminate\Foundation\Console\Kernel as ConsoleKernel;

class Kernel extends ConsoleKernel
{
    protected function schedule(Schedule $schedule)
    {
        $schedule->command('inspire')
                 ->hourly()
                 ->when(feature_toggle('Inspire Command'));
    }
}

Use with Laravel Validation

There are three ways you can use the validation logic:

• Simple String
• Via Illuminate\Validation\Rule
• requiredIfRule Method on FeatureToggleApi

Simple String

Use the normal simple string signature via required_if_feature:

required_if_feature:{name},{status}

Where status is an optional parameter. status will default to true (truthy). name parameter is required.

use Illuminate\Support\Facades\Validator;

Validator::make(request()->all(), [
    'phone' => 'required_if_feature:Require phone',
]);

Validator::make(request()->all(), [
    'phone' => 'required_if_feature:Require phone,on',
]);

Via Illuminate\Validation\Rule

A macro method has been added to the Rule class called requiredIfFeature:

use Illuminate\Support\Facades\Validator;
use Illuminate\Validation\Rule;

Validator::make(request()->all(), [
    'phone' => Rule::requiredIfFeature('Require phone'),
]);

Validator::make(request()->all(), [
    'phone' => Rule::requiredIfFeature('Require phone', true),
]);

requiredIfRule Method on FeatureToggleApi

You may also use the requiredIfRule method on the FeatureToggleApi/feature_toggle_api Facade or helper function:

use FeatureToggle\Facades\FeatureToggleApi;
use Illuminate\Support\Facades\Validator;

Validator::make(request()->all(), [
    'phone' => FeatureToggleApi::requiredIfRule('Require phone'),
]);

Validator::make(request()->all(), [
    'phone' => feature_toggle_api()->requiredIfRule('Require phone', true),
]);

Toggle Providers

The default feature toggle providers are as follows:

• conditional
• eloquent
• local (config)
• querystring
• redis
• session

You can pass the feature_toggle_api helper function one of the above strings to get the toggle provider:

$redisProvider = feature_toggle_api('redis');
// return false
$redisProvider->isActive('Example Off');

$sessionProvider = feature_toggle_api('session');
// return false
$sessionProvider->isActive('Example False');

Or you can access each toggle provider via:

• feature_toggle_api()->getConditionalProvider()
• feature_toggle_api()->getEloquentProvider()
• feature_toggle_api()->getLocalProvider()
• feature_toggle_api()->getQueryStringProvider()
• feature_toggle_api()->getRedisProvider()
• feature_toggle_api()->getSessionProvider()

E.g.

$localProvider = feature_toggle_api()->getLocalProvider();
// return false
$localProvider->isActive('Example');

// Returns by reference.
$conditionalProvider = feature_toggle_api()->getConditionalProvider();
$conditionalProvider->setToggle('Example', function() { return true; });
// return true
$conditionalProvider->isActive('Example');

// Request ?feature=Example
$queryStringProvider = feature_toggle_api()->getQueryStringProvider();
// return true
$queryStringProvider->isActive('Example');

$eloquentProvider = feature_toggle_api()->getEloquentProvider();
// return false
$eloquentProvider->isActive('Example');

If you would like to set the providers in code you may call the following in the boot method of your AppServiceProvider:

feature_toggle_api()->setProviders([
    [
        'driver' => 'conditional',
    ],
    [
        'driver' => 'eloquent',
    ],
]);

Add Additional Toggle Providers

You may add additional custom toggle providers or override the default toggle providers by adding them to the drivers key within config/feature-toggle.php:

return [
    'drivers' => [
        'local' => \App\FeatureToggle\LocalToggleProvider::class,
        'redis' => \App\FeatureToggle\RedisToggleProvider::class,
        'session' => \App\FeatureToggle\SessionToggleProvider::class,
    ],
];

Then just add them in the order you'd like them to be checked within providers as you would the defaults:

return [
    'providers' => [
        [
            'driver' => 'session',
        ],
        [
            'driver' => 'conditional',
        ],
        [
            'driver' => 'redis',
        ],
        [
            'driver' => 'local',
        ],
    ],
];

Local Feature Toggles

To add new toggle(s) you will need to update the published config/feature-toggles.php file:

return [
    // ...
    'toggles' => [
        'Example' => env('FEATURE_EXAMPLE'),
        'Show Something' => env('FEATURE_SHOW_SOMETHING'),
    ],
];

Toggle Parsing

The value passed from the .env file or set directly within config file can be:

• A boolean: true/false
• An int version of boolean: 1/0
• Finally all supported values of filter_var($value, FILTER_VALIDATE_BOOLEAN)

Conditional Feature Toggles

To add new conditional toggle(s) you will need to call feature_toggle_api()->setConditional method:

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Cache;

// calling conditional function is deferred by default
feature_toggle_api()->setConditional('Example', function (Request $request) {
    $user = $request->user();
    return $user instanceof \App\User && $user->email === 'johndoe@example.com';
});

// OR call right away by passing false as $defer parameter
feature_toggle_api()->setConditional('Example', function () {
    return Cache::get('feature:example');
}, false);

NOTE: The function passed to setConditional does not get called right away by default, it is deferred to allow the Laravel app to bootstrap User/Session information. The conditional function is only called once and the value is cached to help prevent expensive operations from being recalculated when adding additional conditional toggles. Because of this design it is best to define these in AppServiceProvider@boot or in a FeatureToggleServiceProvider@boot that you create.

Eloquent Feature Toggles

To use the eloquent driver you will need to update the feature-toggle config or setProviders method call, place the following within the providers key:

[
    'providers' => [
        [
            'driver' => 'eloquent',
        ],
    ],
];

OR

feature_toggle_api()->setProviders([
    [
        'driver' => 'conditional',
    ],
    [
        'driver' => 'eloquent',
    ],
    [
        'driver' => 'local',
    ],
]);

NOTE: Be sure to place this value in the order you would like it to be prioritized by the feature toggle api.

Database Migration

By default the migration for feature_toggles is not loaded, to load this you can update the options key within feature-toggle config setting the useMigrations value to true:

return [
    'options' => [
        'useMigrations' => true,
    ],
];

If you would like to set the useMigrations in code you may call the following in the register method of your AppServiceProvider:

use FeatureToggle\Api;

Api::useMigrations();

You may also publish the migrations to your application by running the following:

php artisan vendor:publish --tag="feature-toggle-migrations"

Once you've used one of the methods above, you can run the following command to update your database with the feature_toggles migration(s):

php artisan migrate

Eloquent Model

If you would like to use a different eloquent model you may do so by adding model to the config file:

return [
    'providers' => [
        [
            'driver' => 'eloquent',
            'model' => \App\FeatureToggle::class
        ],
    ],
];

QueryString Toggle Provider

To use the querystring driver you will need to update the feature-toggle config or setProviders method call, place the following within the providers key:

[
    'providers' => [
        [
            'driver' => 'querystring',
        ],
    ],
];

When making a request to your application you may now use the following query strings to make feature toggles active/inactive:

• feature
• feature_off

e.g. http://localhost/?feature=Example&feature_off[]=Example%20Off&feature_off[]=Example%20Query%20String

The following example will result in Example as active and Example Off/Example Query String as inactive. NOTE: This will only be true if the querystring provider is placed above other toggle providers that haven't already defined these feature toggles.

Configure Query String Keys

If you'd like to configure what the active/inactive feature toggle input keys are you may add activeKey and inactiveKey to config file.

Below is an example of configuring the query string keys as active and inactive:

return [
    'providers' => [
        [
            'driver' => 'querystring',
            'activeKey' => 'active',
            'inactiveKey' => 'inactive',
        ],
    ],
];

Add Api Key Authorization

To keep users or bad actors from enabling/disabling feature toggles via the querystring toggle provider you may configure the driver with a token/api key. By default the query string input is configured as feature_token, but this can be also be configured to any value.

return [
    'providers' => [
        [
            'driver' => 'querystring',
            'apiKey' => env('FEATURE_TOGGLE_API_KEY'),
            // Optionally change to something different.
            // 'apiInputKey' => 'feature_toggle_api_token',
        ],
    ],
];

Redis Toggle Provider

To use the redis driver you will need to update the feature-toggle config or setProviders method call, place the following within the providers key:

[
    'providers' => [
        [
            'driver' => 'redis',
        ],
    ],
];

There are three options that can be configured:

• key, defaults to feature_toggles
• prefix, defaults to null
• connection, defaults to default

return [
    'providers' => [
        [
            'driver' => 'redis',
            'key' => 'toggles', // Optional, otherwise 'feature_toggles'
            'prefix' => 'feature', // Optional
            'connection' => 'toggles', // Must match key in database.redis.{connection}
        ],
    ],
];

Current implementation requires the array of toggles to be serialized in redis, you can use Illuminate\Cache\RedisStore forever method to persist toggle values.

Session Toggle Provider

To use the session driver you will need to update the feature-toggle config or setProviders method call, place the following within the providers key:

[
    'providers' => [
        [
            'driver' => 'session',
        ],
    ],
];

Frontend Feature Toggle Api

Place the following in your main layout blade template in the <head> tag.

<script>
    window.activeToggles = Object.freeze({!! feature_toggle_api()->activeTogglesToJson() !!});
</script>

Then create a new js file within resources/js called featureToggle.js:

const toggles = Object.keys(window.activeToggles || {})

export const featureToggle = (name, checkActive = true) =>
    checkActive ? toggles.includes(name) : !toggles.includes(name)

Expose on the window within app.js:

import { featureToggle } from './featureToggle'

// ...

window.featureToggle = featureToggle

and/or simply use featureToggle within your other js files:

import { featureToggle } from './featureToggle'

if (featureToggle('Example')) {
    // do something about it.
}

and/or create a Feature component that uses featureToggle.js:

// Feature.js
import { featureToggle } from './featureToggle'

export const Feature = ({ name, active: checkActive = true, children }) => {
    return featureToggle(name, checkActive) && children
}

// App.js
import React, { Component, Fragment } from 'react'
import { Feature } from './Feature'

class App extends Component {
    render() {
        return (
            <Fragment>
                <Navigation />
                <Feature name="Show Something">
                   <Something />
                </Feature>
                <Feature name="Show Something" active={false}>
                   <p>Nothing to see here!</p>
                </Feature>
            </Fragment>
        )
    }
}

Road Map

v1.x

• Local Feature Toggles via Config.
• Conditionally Enable/Disable Feature Toggles e.g. Authorization.
• Eloquent Feature Toggles.
• Query String Feature Toggles.
• Integrate toggles into:
  • Blade
  • Middleware
  • Validation

v2.x

• Create/update toggles via common contract interface.
• Create Command to create/update toggles to be active/inactive.
• Classmap Feature Toggles (FeatureToggleServiceProvider similar to AuthServiceProvider $policies).