Infrastructure as Code (IaC) is the state-of-the-art method of managing resources both on-premise and in the cloud. It is an approach to automate the complete lifecycle of any resource utilizing software development practices. The main goal is a consistent and repeatable representation of the entire developed system. One of the most popular IaC tools is Terraform. With Terraform, infrastructure requirements are formalized as declarative configuration files consisting of providers and resources. A provider is a plugin that allows interaction with external entities like AWS or other APIs. Each provider defines a set of data sources and resource types. A resource, on the other hand, describes some infrastructure object like a virtual machine, DNS record, or Network. 
This thesis consists of two parts. First, you will develop and outline how REST APIs can be implemented in custom Terraform providers. During the second part, you will design and implement a REST API for an existing network stack and use your approach to implement the API in Terraform. 

We propose the development of a toolkit for automated and user-configurable distributed deployment of a Swift program implementing a web service. The web service is defined as a composition of individual services, via the Apodini internal domain-specific language (DSL) [Sch20]. Our toolkit analyses the web service’s structure as expressed via the DSL, taking into account additional nonfunctional requirements. From this information it determines the deployment strategy which best satisfies these constraints. The resulting distributed system can be deployed to arbitrary target platforms, ranging from conventional web servers to FaaS providers such as AWS Lambda.

A fog computing architecture represents a solution for the challenges introduced by modern distributed systems containing countless heterogeneous and interconnected components. Monitoring these fog computing architectures is typically achieved by central cloud monitoring platforms, which result in increased network traffic and static responsibilities of maintenance teams. Decentralized Observability addresses the challenges above by transferring the responsibility of monitoring a system from a central cloud monitoring platform to each of the individual components. In the course of this thesis, we will try to integrate this approach into the declarative component-based Apodini framework and use its Domain-Specific Language (DSL) to automate most of the resulting observability overhead. The thesis contributed to the Apodini open source project: https://github.com/Apodini/Apodini.

Modern server-side development faces a multitude of challenges. While many of those challenges are solved well by most modern web-frameworks, the following are still subject of active research: Web services often have to use a variety of middlewares to serve a heterogenous set of clients. Moreover, agile development methodologies lead to constant change in regards to both, application logic and middleware. Apodini is a prototypic server-side framework that aims to solve these challenges by providing a declarative and composable syntax for defining a web-service, establishing a full abstraction between the implemented application logic, the web-service’s structure and the middleware in use. This thesis explores different strategies to improve the Apodini framework in terms of maintainability and runtime-performance. The thesis contributed to the Apodini open source project: https://github.com/Apodini/Apodini.

When designing web services, requirements traceability is a challenging task. In the software engineering process, functional and non-functional requirements are defined in the Requirements Elicitation. Those requirements are structured and formalized in the Analysis, System Design and Object Design activities before the developed models are mapped to code. Therefore, tracing requirements through the individual design artifacts to the actual implementation is a challenge for software engineers. Requirements Traceability is essential as it enables us to verify our implementation against the requirements expected from the system. Furthermore, it improves the ability to deal with the change of requirements, yielding an improved iteration speed of the software engineering process. The thesis explores how a tighter coupling between the implementation and software engineering activities can improve traceability and thus verifiability and changeability of requirements. The research is done in the context of requirements typically encountered with web services, including non-functional requirements like security, performance and availability. The Apodini framework is used for the instantiation and validation of requirements. The thesis contributed to the Apodini open source project: https://github.com/Apodini/Apodini.