Browsing by Author "Stieß, Sarah Sophie"

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Open Access
Implementierung von änderungstoleranten Enumerationen in SKilL
(2018) Stieß, Sarah Sophie
Diese Arbeit befasst sich mit der Implementierung von enum-Typen in SKilL. Die bisherige Implementierung wird durch eine neue ersetzt, in der enum-Typen keine Felder mehr haben und auf enum-Typen der Zielsprache abgebildet werden. Diese Abbildung hat das Problem, dass die enum-Typen der Zielsprachen nicht änderungstolerant sind, Änderungstoleranz aber eine zentrale Eigenschaft von SKilL ist. In dieser Arbeit wird die Lösung dieses Problems beschrieben. Die Arbeit beschreibt, welche Auswirkungen die gefundene Lösung auf die bereits vorhandenen SKilL-Komponenten hat. Es wird beschrieben, welche von ihnen weiter verwendet werden können und welche verändert beziehungsweise neu hinzugefügt werden müssen. Die Arbeit beschreibt außerdem eine entsprechende Implementierung in Java und C++. Die neuen enum-Typen erfordern Änderungen an den Code-Generatoren, die von dieser Arbeit ebenfalls beschrieben werden. Die entstandene Implementierung von enum-Typen in SKilL wurde ausgiebig getestet. Eine Beschreibung der durchgeführten Tests ist auch Teil dieser Arbeit.
Open Access
Tracing the impact of SLO violations on business processes across a microservice architecture with the saga pattern
(2021) Stieß, Sarah Sophie
Context. Applications in the microservice architecture style consist of many individual services. SLOs describe the quality at which they provide a functionality, as an example their responsetime or availability. Patterns exist to handle recurring problems better. Among these is the saga pattern [Ric18], which deals with transactions distributed across multiple services. Problem. SLO violations may propagate across the architecture and cause unintended behaviour in the business process. Patterns may hide the cause of a business process’ behaviour. As for the saga pattern, an SLO violation may trigger the rollback of a transaction. The process owner notices the rollback. But a rollback is an acceptable behaviour for a transaction, such that they either do not not question the rollback’s origin at all or they do question it but cannot find any fault in it. Thus, the connection to the SLO violation remains unidentified. Objective. This thesis’ objective is to expose the impact of SLO violations on a business process in the presence of the saga pattern. Method. The means to achieve this objective is a notification that informs a user about the SLO violation and its possible impacts on the business process and a modelling language for models that capture all knowledge required to create such notifications. The user received the notification as an issue. An expert survey evaluates the language and the concept and a experiment assures that the modelling language fulfils its purpose. The experiment employs the T2-Project as a reference architecture. Result. This thesis’ results include the aforementioned modelling language, the concept for the notification, and a prototype to calculate impacts. The language connects models of architectures with those of business processes while reusing existing models. The prototype uses models according to the designed language and calculate the impact of SLO violations upon receiving notice about a violation. It also creates issues for these impacts. There is an expert survey and an experiment that attempt to validate this thesis content. Conclusion. The designed modelling language is of use when connecting existing models of architectures and business processes while also representing an instance of the saga pattern. Models according to the language are useable to calculate the impact of SLO violations on the business process. Notifications about impacts that are not apparent in the business process are helpful.