In Laravel, there is a clear recommendation to use environment variables env() exclusively in configuration files. Yet, time and again, you see code where env() is used directly in application logic or controller functions. This can have serious impacts on the performance and stability of the application, especially in production environments.

In this article, I will address the problems that can arise from the direct use of env() and explain why using the config() helper in Laravel is the better approach.

Problem 1: Caching and env()

One of the biggest problems with the direct use of env() in application logic is configuration caching. When Laravel's command php artisan config:cache is executed, the entire configuration is cached into a single file to optimize performance. However, this has the consequence that env() calls outside of configuration files no longer work. Once the configuration has been cached, Laravel no longer accesses the .env file, but uses the cached configuration instead.

This means that env() calls in your code no longer return correct values at runtime. This can lead to unpredictable errors in the production environment, while it seemingly works in the development environment. This behavior is particularly dangerous because it often lulls developers into a false sense of security.

Here is a typical scenario:

  • In development, the code works because php artisan config:cache is not used.
  • In production, the same script leads to errors because the environment variables can no longer be read correctly.

Problem 2: IO Load and Performance Degradation

Another aspect that is often overlooked is the performance impact from frequent use of env(). Every time env() is called, the application must access the file system to read the variable from the .env file. This additional input/output overhead can add up and impair application performance, especially for applications with high traffic.

Instead, Laravel uses the config() helper, which reads values from the configuration files. These values are kept in memory and are thus much faster to access without constantly loading the file system.

Problem 3: Limitations of Environment Variables

Environment variables have a number of limitations that make their use problematic in more complex scenarios:

  1. No structure: Environment variables are always strings. You cannot directly store complex data structures like arrays or objects. So if you need data structures, you must serialize them as strings and then deserialize them again in your code, which introduces additional complexity and sources of error.

  2. Visibility and maintainability: Environment variables are available system-wide, which can lead to collisions between different applications. It is often difficult to track which variables are used by which application. In configuration files, on the other hand, all settings are stored centrally and in a structured manner.

  3. Missing documentation and default values: In an .env file, default values are not always clearly visible, and it can happen that developers forget to define important environment variables. By using configuration files, you can define default values and ensure that the application works even without a complete .env file.

Best Practices: Using Configuration Files

The recommended approach in Laravel is to use configuration files in combination with the config() helper. So instead of calling env() directly in your application logic, you should create your own configuration files and access env() there. Here is an example:

// config/myconfig.php
return [
    'myvalue' => env('MY_VALUE', 'default_value'), // 'default_value' is the default value if the variable is missing in the .env file
];

// Access in your application logic:
$value = config('myconfig.myvalue');

Through this method, you ensure that all environment variables are defined in a central location and you benefit from the advantages of config caching.

Conclusion

The direct use of env() in your Laravel application is a bad practice that can lead to serious problems in production environments. It not only causes performance issues through additional IO load, but can also result in your application no longer working properly after a config:cache command.

Instead, you should only use environment variables in configuration files and rely on the config() helper in your application logic. This not only improves performance, but also makes your application more robust and maintainable.

Remember: Configuration files are your friend – env() is not.