Web services offer reusable, well-designed and pretested component solutions for their consumers. Whilst striving for stability and reliability, web services experience numerous evolutive phases due to changes in application domain or changed requirements, and often cause breaking compatibility. This thesis proposes automated generation of migration guides, that encapsulate a generic description on how to migrate breaking changes. Our approach focuses on generating migration guides for web services built on Apodini, a novel internal Domain Specific Language that describes web services declaratively. The applicability of our research is demonstrated on industry projects from telecommunication branch and healthcare industry in cooperation with Mobile Software AG. You can find the open source implementation at https://github.com/Apodini/ApodiniMigrator.

The operation of large amounts of data generated by Internet of Things (IoT) devices is challenging for classic centralized IoT systems. Fog Computing solves this issue by shifting the computing responsibility from a centralized instance to fog devices, thus enables large heterogenous environments with different device types. Moving away from a central approach also allows more dynamic environments with devices entering and leaving the network arbitrarily. In this thesis we present an approach that enables the simultaneous and automatic deployment of a webservice to an heterogeneous IoT environment. Our approach assumes certain IoT typical constraints, such as hardware restrictions on devices, limited access due to private and secure networks, heterogenity of devices and nodes as well as dynamic topology changes. To handle the latter, our approach is able to register changes in the network at runtime and reflect them in the components and services. To showcase our approach, we will present an example using a web service created with the Apodini framework that we deploy in selected scenarios. You can find the open source implementation at https://github.com/Apodini/ApodiniIoTDeploymentProvider.

The thesis aims to identify and address the challenges faced when using domain-specific languages (DSLs) to declaratively express the interface of a web service based on the service’s structure and the semantics of its implementation. Apodini proposes an internal DSL, with the intention of using a web service’s structure in combination with run-time type introspection to automatically generate, by the means of so-called interface exporters, client-facing interfaces for a variety of different protocols, such as REST, HTTP, WebSockets, or others. The approach of deriving service interfaces dynamically from an implementation presents an interface exporter developer with several new challenges, such as properly mapping the semantics of the service as expressed in Swift to the semantics of the respective protocols. We will conduct an expansive evaluation by adding two new interface exporters to Apodini: gRPC and GraphQL. These two interface exporters will serve as a validation of our general work on Apodini, and will be used to determine the quality, accuracy, and reliability of the API mappings generated by Apodini.