Automatic Abstraction of Flow of Control in a System of Distributed Software Components

CloudFoundry (CF) provides an open source platform-as-a-service software for deploying scalable software systems to the cloud. The architecture for CF is distributed by design and consists of several components which interact with one another through a message-oriented middleware. This message-oriented distributed design delivers on the scalability and resiliency requirements of the platform. In such a complex distributed multicomponent system, there is a steep learning curve for software developers to understand how components interact, what messages are exchanged between them, and how the message exchanges affect the behaviour of the system. In particular developers find it difficult to identify the execution flows, the authentication flows, interactions with the persistence layer, etc. We have developed a framework that allows interpreting the behaviour of the system by analyzing the exchanged messages between components, inspecting message contents, and extracting data and control flow across components. The paramount aim is to improve developers’ understandability of the system and to examine software resiliency through approaches like bug injection and message alterations. An initial version of our framework was released to the CF community and we have collected feedback that indeed show that we are achieving some of our goals.