Managing User-Provided Environment Variables

User-provided variables are your custom environment variables, created as key-value pairs. You define them manually to pass data such as:

• API tokens
• Feature flags
• Configuration values
• External URLs

Caution: Avoid using user-provided environment variables for security-sensitive information like credentials. They might unintentionally appear in cf CLI output and Cloud Controller logs.

Example

Our sample applications are implemented to expect the variable DARK_MODE. This variable allows you to customize the UI theme of an app. Here’s a snippet from the source code of the sample Node.js app:

const DARK_MODE = process.env.DARK_MODE === 'true';

Let’s create an environment variable that switches the theme of the sample app from the default to a dark theme. This is how our sample app looks like by default:

1. Go to the Cloud Foundry > Spaces in the left navigation menu.

   

2. Go to a space. This opens the Applications page.

3. Click the name of the application which you want to customize with your own variable.

   

4. Go to User-Provided Variables in the left navigation menu.

   

5. Choose Create Variable.

   

6. Provide a Key and a Value. These values are case-sensitive.

   

7. Choose Create.

   The user-provided variable is now created.

   

   To apply the change, you need to restart your application.

8. Go to the Overview page of your application.

   

9. Choose Restart.

   

10. Click the URL of the application.

    As you can see, the interface of the app has switched to the dark theme.

    

When you no longer need the variable and the customization it brings, delete it:

1. On the User-Provided Variables page, choose the Delete button in the Actions column.

   

2. Choose Delete to confirm the action.

   

After you delete the variable, restart the application as described in steps 8-10 of Create a user-provided environment variable or restage it. Otherwise, the change won’t take effect.