Microservices and the First Law of Distributed Objects (2014)

An anecdote I like to tell:

I once participated in implementing a system as a monolith, and later on handled the rewrite to microservices, to 'future-proof' the system.

The nice thing is that I have the Jira tickets for both projects, and I have actual hard proof, the microservice version absolutely didn't go smoother or take less time or dev hours.

You can really match up a lot of it feature-by-feature and it'll be plainly visible that the microservice version of the feature took longer and had more bugs.

And Imo this is the best case scenario for microservices. The 'good thing' about microservices, is once you have the interfaces, you can start coding. This makes these projects look more productive at least initially.

But the issue is that, more often than not, the quality of the specs are not great to awful, I've seen projects where basically Team A and Team B coded their service against a wildly different interface, and it was only found in the final stretch that these two parts do not meet.

> While small microservices are certainly simpler to reason about, I worry that this pushes complexity into the interconnections between services

100% true in retrospect.

I dream of a SQL like engine for distributed systems where you can declaratively say "svc A uses the results of B & C where C depends on D."

Then the engine would find the best way to resolve the graph and fetch the results. You could still add your imperative logic on top of the fetched results, but you don't concern yourself with the minutiae of resilience patterns and how to traverse the dependency graph.

AI has also changed the dynamics around this. Splitting things into smaller components now has a dev advantage because the AI program better with smaller scope

99% of systems out there are not truly microservices but SOA(fat services). A microservice is something that send emails, transforms images, encodes video and so on. Most real services are 100x bigger than that.

Secondly, if you are not doing event sourcing from the get go, doing distributed system is stupid beyond imagination.

When you do event sourcing, you can do CQRS and therefore have zero need for some humongous database that scales ad infinitum and costs and arm and a leg.

A lot of this first law was specifically coupled to how these systems often hid that distributed objects were distributed. In the past 10 years, async has become far more common place, and it makes the distributed boundary much less like a secret special anomaly that you wouldn't otherwise deal with and far more like just another type of async code.

I still thoroughly want to see capnproto or capnweb emerge the third party handoff, so we can do distributed systems where we tell microservice-b to use the results from microservice-a to run it's compute, without needing to proxy those results through ourself. Oh to dream.