Custom .env variable on Codeigniter 4

Question

Normally if i want to change the database hostname in CI4 project i will change it in .env file and change the

database.default.hostname = localhost

but now i need to use MYSQL_HOST in env to change the hostname like so

MYSQL_HOST = localhost

can i do that in CI4? it will give error if i change the Database.php file to

public $default = [
    'DSN'      => '',
    'hostname' => getenv('MYSQL_HOST'),
    'username' => '',
    'password' => '',
    'database' => '',
    'DBDriver' => 'MySQLi',
    'DBPrefix' => '',
    'pConnect' => false,
    'DBDebug'  => (ENVIRONMENT !== 'production'),
    'charset'  => 'utf8',
    'DBCollat' => 'utf8_general_ci',
    'swapPre'  => '',
    'encrypt'  => false,
    'compress' => false,
    'strictOn' => false,
    'failover' => [],
    'port'     => 3306,
];

Answer 1

I found the answer, lets say you have this in you .env file

MYSQL_HOST = localhost
MYSQL_USERNAME = root
MYSQL_PASSWORD = root

so if you want to change hostname of CI4 database you can add

$this->default['hostname'] = getenv('MYSQL_HOST');

inside __construct() in app/config/Database.php

so it will be look like this

public function __construct()
{
    parent::__construct();

    // Ensure that we always set the database group to 'tests' if
    // we are currently running an automated test suite, so that
    // we don't overwrite live data on accident.
    if (ENVIRONMENT === 'testing') {
        $this->defaultGroup = 'tests';
    }
    $this->default['hostname'] = getenv('MYSQL_HOST');
    $this->default['username'] = getenv('MYSQL_USERNAME');
    $this->default['password'] = getenv('MYSQL_PASSWORD');
}

well this is only if you want to custom your .env and dont want to use the default CI4 database.default.hostname