Lagom notes and facts

This is just a list of notes and facts I have gathered about Lagom. I’m the kind of person that asks 1 million questions and likes to know why things are done.

Why does Lagom use Cassandra as an event store system?

Lagom uses Cassandra as it’s event store. I wanted to know why they would choose Cassandra so I did some digging.  I found the following video helpful in understanding why anyone would use Cassandra for an event store instead of EventStore itself.  The video is not about Lagom, however it is about Cassandra and CQRS/Event Sourcing and why you would choose Cassandra as an event store. Basically Cassandra has features that are required for Event Sourcing and make it a good fit for it.

Why does Lagom use KAFKA as a Message Broker?

The documentation mentions using KAFKA as a Message Broker. I wanted to know why?  This article helped clarify what the difference between a message bus and a message broker.  Basically a broker gives a little less coupling with some other nice features. A message bus is more strict with a Schema like a traditional RDBMS database system, a message broker is more free like a NoSql database it has no Schema. Read the article for the other benefits and differences.

Codecentric: CQRS and Event Sourcing Applications with Cassandra

This video explains how to handle event sourcing with Cassandra

I also found this link to be helpful in understanding why Lagom would use Cassandra instead of EventStore. That article has a nice comparison of Cassandra vs other similar software used for event storage. A quick look at the features is all it takes.


Lagom resources


Introduction to Lagom

This is a video introduction and quick explanation of Lagom

Lagom Developer Setup

This short video describes how to setup a Lagom project

Events-First Microservices with Lagom by Gideon de Kok

Tom Peck – Building Better Microservices with Lagom

What can Lagom Do for you?

CQRS and Event Sourcing with Lagom by Miel Donkers

From CRUD to Event Sourcing Why CRUD is the wrong approach for microservices

This video doesn’t mention it but it is about Lagom and how it is used to create microservices. This is a video  I will watch more than once and write notes about.  This video is complete with some code examples found here on github. This is a very helpful video if you are wondering how the hell Lagom works overall.


Your first microservices using Scala and Lagom. This is an interesting short article about Lagom. It is more or less a quick explanation of Lagom and how it works.

Deploying a Lagom Application to Openshift.  A lightbend article about how to deploy an application to to openshift.

Lagom Migration guide. This guide covers the changes from Lagom 1.4 to 1.5 the improvements etc. See the Docker images and deployment specs about kustomize

Here is a useful article about CQRS and Event Sourcing and how it relates to Lagom. CQRS and Event Sourcing with Lagom

Persistent read side in Lagom explained

Data persistence in Lagom  An article about saving your data in a Lagom Framework system.

Here is a really good article about lagom. If you are wondering why use lagom, especially since it uses AKKA and Play and you can just do that yourself, then this is the article for you.