Summary

In this chapter, we have seen more event-driven systems with a variety of advanced and complex architectures that can be designed. We have presented some of the flexibility and power that event-driven design can bring to a design, but also the challenges attached to event-driven design.

We started by presenting common systems such as logs and metrics as event-driven systems, as they are, and considered how looking at them in this way allows us to create alerting and feedback systems that can be used to control the source of the events.

We also presented an example with Celery of a more complex pipeline, including the usage of multiple queues and shared storage to generate multiple coordinated tasks, such as resizing a video and extracting a thumbnail.

We presented the idea of a bus, a shared access point for all events in the system, and looked at how we can generate more complex systems where events are delivered to multiple systems and cascade into complex actions...