[Proposal] Dotenv implementation

[jasonhebert]

Description:

I would like to suggest making available within the bootstrapping process the instance of Dotenv used to load environment variables and provide a mechanism to add and enforce validations on the .env file using the Dotenv builtin validators.

Currently the environment variables are loaded within the bootstrap() method of the Illuminate/Foundation/Bootstrap/DetectEnvironment.php class using (new Dotenv($app->environmentPath(), $app->environmentFile()))->load();. The object instance is thrown away and doesn't give developers an easy opportunity to enforce environment variable validations such as required(), notEmpty(), isInteger() or allowedValues().

[Garbee]

Just set the requirements in your AppServiceProvider@register like so:

(new Dotenv(base_path('.env')))->required([
            'SERVICES_STRIPE_PUBLIC',
            'SERVICES_STRIPE_SECRET',
            'SERVICES_EASYPOST_SECRET',
            'MAIL_DRIVER',
            'MAIL_HOST',
            'MAIL_PASSWORD',
            'MAIL_USERNAME',
        ]);

[jasonhebert]

That's all fine @Garbee but it's a bit hacky to have to create a new instance of Dotenv when one was just thrown away.

[Garbee]

What would a good solution look like to the problem look like to you?

[jasonhebert]

What would be nice would be to have that initial instance of Dotenv registered and made available as a singleton so that the instance could be used anywhere in the app without having to reload the .env file each time you need to do a validation. This would give you the ability to do, as an example, things like:

Dotenv::required([
    'MAIL_DRIVER',
    'MAIL_HOST',
    'MAIL_PASSWORD',
    'MAIL_USERNAME',
]);

Dotenv::required([
    'SERVICES_STRIPE_PUBLIC',
    'SERVICES_STRIPE_SECRET',
    'SERVICES_EASYPOST_SECRET',
])->notEmpty();

[sisve]

You should use cached configurations in production, and dotenv will never be loaded in Laravel 5.2 (and newer). This means that some kind of environment-validation function should only execute when the config is cached; and not on normal requests.

Relevant comments:
vlucas/phpdotenv#76 (comment)
vlucas/phpdotenv#76 (comment)