Question
Answer and Explanation
The files .env and .env.local are commonly used in software development to manage environment variables, particularly in projects that use tools like dotenv for configuration. However, they serve slightly different purposes:
1. `.env` File:
- This file is the primary location for storing environment variables in a project. It’s intended to hold default values, secrets, and other configurations necessary for the application to run correctly.
- It's common practice to include the .env file in version control (e.g., Git) but typically exclude sensitive information from it. This is often achieved through gitignore rules, where it’s common to see something like .env in the .gitignore file to prevent accidental commit of keys or sensitive information.
- Developers might use a sample .env.example or .env.sample file, which contains the structure of variables with example values. This serves as a template for other developers and ensures the needed variables are in place.
2. `.env.local` File:
- The .env.local file is used to override the default environment variables defined in the .env file. It’s usually intended for local development and testing environments.
- This file is almost always excluded from version control. This prevents accidental changes to the local environment from affecting other developers or production environments. It’s where a developer may keep their custom api keys or database connection strings.
- When a project is configured to load environment variables, .env.local is often prioritized over .env, so that any variables present in both files, values from .env.local will take precedence. This helps ensure a developer can customize their environment without changing the project's base configuration.
3. Precedence and Usage:
- When your application loads environment variables, it first looks for .env.local. If a variable is defined there, its value is used. If not, the application checks .env. This way, the .env.local is used for custom local settings.
4. Example Scenario:
- Let's say in .env you have API_KEY=default_key, and in your .env.local file you have API_KEY=my_local_key. When your application runs locally, the API_KEY would resolve to “my_local_key”, as the value defined in .env.local will override the one in the .env.
In summary, while .env provides the base settings for your application, .env.local offers a method to locally override those settings without committing changes to the base configuration. This approach is very effective for managing local development configurations.