Muon

This article was spawned from a conversation I had with Ben Wilcock on his article about building an event sourced system on Cloud Foundry using Axon, which you can read here. We covered some interesting topics, including some critiques of the model so he encouraged me to write up my thoughts on Event Architectures.

No small topic there, thanks Ben!

This is an interesting topic, with a lot of potential pitfalls.

This article introduces a project I’ve been working on for the past few years in one form or another. Muon

For the past bunch of years, I’ve been working with distributed systems, often with a messaging component. This is a fun and rewarding part of software development, up there with UI development. It’s fairly involved, and often hard, but covers lots of different areas, both deeply theoretical and very practical. Once you solve an issue involving a race condition that requires networks, heavy load and specific hardware to trigger, you become far more interested in the world of concurrency, networking and spreading beyond the regular languages you are used to!

I’m currently finishing cleaning up a new application framework built upon the Muon communications toolkit, called Newton

In this framework, we provide support for building Event Sourced Aggregate Roots , Stream processed Views, long running transactional Sagas, commands and general event handling. Lots of good things.

I want to describe the Aggregate Root handling, as I had an epic fight with Spring/ Java Generics today that left me somewhat drained!

TL/DR

• Microservices == distributed systems. RPC is well known for creating fragility in systems, Muon offers a way of building others kinds of APIs, based on Reactive principles while keeping your existing internal frameworks, languages and runtimes.
• Muon gives you very portable, polyglot message based APIs, across infrastructures. This lets you focus on the functionality you need for your business, rather than adopting a vendor best practice and becoming locked in.
• It is based on CSP, and is focused squarely on communication as a way of expressing interaction about state. This lets you build highly distributed systems without falling into the traps of
• This approach is implemented as Muon “protocols”, message based apis and defined interactions between services that implement well known communication and data architecture patterns. This lets you explicitly use particular architectures, such as event sourcing or SEDA, and know that it is correct, works well and is portable across languages, runtimes, frameworks and communication technologies (gRPC, Kafka, AMQP etc)
• It allows you to adopt advanced technologies as a tactical decision later on in your project, without impact on your codebase. This includes tech such as Kafka, Hazelcast and Cassandra, knowing that as you need to scale your system, you can.

I have been a big fan of the Reactive approach to build software for as long as its been around. My view on the world of Microservices today is that there are several strands you need to weave together to make your software thrive.