Building Event-Driven Microservices

Chapter 12. Lightweight Framework Microservices

Lightweight frameworks provide similar functionality to heavyweight frameworks, but in a way that heavily leverages the event broker and the container management system (CMS). Unlike heavyweight frameworks, lightweight frameworks have no additional dedicated resource cluster for managing framework-specific resources. Horizonal scaling, state management, and failure recovery are provided by the event broker and the CMS. Applications are deployed as individual microservices, just as any BPC microservice would be deployed. Parallelism is controlled by consumer group membership and partition ownership. Partitions are redistributed as new application instances join and leave the consumer group, including copartitioned assignments.

Benefits and Limitations

Lightweight frameworks offer stream processing features that rival those of heavyweight frameworks, and in a number of cases, exceed them. Materialization of streams into tables, along with simple out-of-the-box join functionality, makes it easy to handle streams and the relational data that inevitably ends up in them. Note that while table materializing functionality is not unique to lightweight frameworks, its ready inclusion and ease of use are indicative of the complex stateful problems that lightweight frameworks can address.

The lightweight model relies upon the event broker to provide the mechanisms for data locality and copartitioning through the use of internal event streams. ...