Infrastructure in Code: Towards Developer-Friendly Cloud Applications

The popularity of cloud technologies has led to the development of a new type of applications that specifically target cloud environments. Such applications require a lot of cloud infrastructure to run, which brought about the Infrastructure as Code approach, where the infrastructure is also coded using a separate language in parallel to the main application. In this paper, we propose a new concept of Infrastructure in Code, where the infrastructure is deduced from the application code itself, without the need for separate specifications. We describe this concept, discuss existing solutions that can be classified as Infrastructure in Code and their limitations, and then present our own framework called Kotless — an extendable cloud-agnostic serverless framework for Kotlin that supports two cloud providers, three DSLs, and two runtimes. Finally, we showcase the usefulness of Kotless by demonstrating its efficiency in migrating an existing application to a serverless environment.