AWS Cloud Development Kit: Simple Approach to Infrastructure-as-Code

One of the main benefits of using an object oriented programming language is that our resources are actually objects, thus you can call methods on them, something that is not possible in Terraform due to the nature of the Hashicorp Configuration Language (HCL), which behaves more like a Domain Specific Language (DSL) and not a real programming language. The ability of resources having both methods and properties makes code easier to understand, since you can use properties as means to just read data from your resources and use methods for anything that would change the state of that resource.

Your constructs can also implement interfaces that are part of the AWS CDK. In this case our lambda function implements the IGrantable interface, which allows you to pass the lambda as an argument to the “grantReadWrite” method. You can also implement this interface in your custom constructs to simplify granting permissions to any children resources of the construct. This saves a lot of boilerplate code and also makes the code’s intent much clearer with less lines.

Conclusion

Nobody is going to migrate a whole codebase from Terraform to AWS CDK just because you no longer have to memorize every IAM action. This is just a small example of how it makes sense to use an object oriented language to write infrastructure. In my experience, the AWS CDK proves particularly convenient when you want to give more autonomy to development teams. It is more likely that they will adopt a programming language that they already know and are familiar with than an HCL.