The Instapro Show

Discussion on all things Tech, Product and UX

All aboard the Message Bus with Marijn Koesen

In our inaugural episode we are lucky to be joined by Marijn Koesen, Lead Software Engineer at Instapro. We start off discussion by describing what a Message (Service) Bus is, the different components that make up the Bus, and the power of middleware. From here, we touch upon the differing characteristics of each type of Bus (Command, Query and Event), and associated message that is used by each. This leads us on to discuss the different types of transport that are available (synchronous vs. asynchronous) and the Outbox pattern, employed to handle the dual-write problem. With this understanding, we then delve into the history of the Message Bus that is used at Instapro, and how it has evolved over the years. Finally, we discuss a project Marijn is currently working on to bring a Central Event Bus to Instapro, helping shape the way we intend to perform inter-service communication between different Bounded Context going forward.

Outline

  • 00:00:15 - Introduction
  • 00:04:59 - What is a Message Bus?
  • 00:07:58 - What is a Message?
  • 00:11:30 - The different types of Message Bus
  • 00:16:35 - What is a Command Bus?
  • 00:23:30 - CQS and CQRS
  • 00:27:03 - What is a Query Bus?
  • 00:32:27 - What is a Event Bus?
  • 00:35:04 - How do you handle Message Validation?
  • 00:39:45 - Differences between Synchronous and Asynchronous Transport
  • 00:45:35 - History of the Message Bus at Instapro
  • 00:51:45 - What is the Message Queue?
  • 00:59:25 - How the Message Bus/Queue is deployed across Instapro
  • 01:04:09 - What is the Central Event Bus?