Does application.yml support environment variables?

Can I Use Environment Variables in application.yml?

So, you've been trying to use environment variables in your application.yml configuration and hitting some roadblocks, huh? Don't worry, you're not alone. Many developers have faced this issue and asked the same question: "Does application.yml support environment variables?"

Well, the answer is both yes and no. Let me explain.

Understanding the Problem

In the context you provided, it seems you tried to use environment variables in your application.yml file, hoping that they would be automatically resolved. However, you noticed that this wasn't happening, and you wondered if there was a different notation for using environment variables in Spring Boot.

The Alternative Notation (for Rails enthusiasts)

In Rails, you might be used to accessing environment variables like <%= ENV['FOOVAR'] %>, where you can directly reference the environment variable using the ENV object. Unfortunately, Spring Boot doesn't provide a similar notation out of the box.

The Solution: Command-Line Arguments

But wait! There's still a way to achieve what you want. Instead of relying on automatic resolution within application.yml, you can pass the environment variables as command-line arguments.

In your case, you can run your application using the following command:

java -jar my.jar --server.address=$OPENSHIFT_DIY_IP --server.port=$OPENSHIFT_DIY_PORT

By explicitly passing the environment variables as command-line arguments, you ensure that Spring Boot receives them correctly and uses them in your application.

The Benefit of Command-Line Arguments

Using command-line arguments to pass environment variables gives you more flexibility. You can easily switch between different environments by just changing the values during startup, without modifying your application.yml file each time.

A Friendly Reminder

Remember, though, that command-line arguments take precedence over any values specified in application.yml. So, if you provide an environment variable as both a command-line argument and in application.yml, the command-line argument will override the application.yml value.

Reader Engagement: Share Your Thoughts!

Now that you know how to use environment variables in your Spring Boot application, I'd love to hear from you. Have you faced any challenges with environment variables before? How did you solve them? Share your experiences and tips in the comments below!

Let's help each other make Spring Boot development even more awesome! 💪🌟