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First Impressions of Lagom and Initial Comparison to Spring Boot/Cloud

This article by Yannick De Turck and Andreas Evers appeared originally on the Ordina blog.

Meet LagomLightbend’s (formerly Typesafe) new open source framework for architecting microservices in Java. On the 10th of March, Lightbend released the first MVP version of Lagom which is the current version at the time of writing. Although there is currently only a Java API, Scala enthusiasts should not fret because a Scala API is a main priority and well on its way.

Just the right amount

Lagom is a Swedish word meaning “just the right amount”. Microservices have often been categorised as small services. However, Lightbend wants to emphasize that finding the right boundaries between services, aligning them with bounded contexts, business capabilities, and isolation requirements are the most important aspects when architecting a microservice-based system. Therefore, it fits very well in a Domain-Driven Design focused mindset.

Following this will help in building a scalable and resilient system that is easy to deploy and manage. According to Lightbend the focus should not be on how small the services are, but instead they should be just the right size, “Lagom” size services. Lagom, being an opinionated framework, provides a “golden path” from which the developer can deviate if necessary. Being based on the reactive principles as defined in the Reactive Manifesto, Lagom provides the developer a guard-railed approach with good defaults while also allowing to deviate if necessary.

This blogpost will cover our initial impression on the framework together with our opinion on the choices made while architecting the framework. Note that we won’t go too deep into detail in all the different aspects of the framework, for more details refer to Lagom’s extensive documentation. As Lightbend is entering the microservices market with Lagom, we feel obliged to make a fair comparison with existing frameworks out there. In the Java world this is predominantly the Spring stack with Spring Boot and Spring Cloud, standing on the shoulders of giants such as the Netflix OSS. In this current stage, it would be a bit too early to make an in-depth comparison between the two, seeing as you would be comparing a mature project to an MVP. What we can share though, are our initial observations.

Design philosophy

Lagom’s design rests on the following principles:

  • Message-Driven and Asynchronous: Built upon Akka Stream for asynchronous streaming and the JDK8 CompletionStage API. Streaming is a first-class concept.
  • Distributed persistence: Lagom favours distributed persistence patterns using Event Sourcing with Command Query Responsibility Segregation (CQRS).
  • Developer productivity: Starting all microservices with a single command, code hot reloading and expressive service interface declarations are some examples of Lagom’s high emphasis on developer productivity.

Building blocks

The Lagom framework acts as an abstraction layer upon several Lightbend frameworks and consists of the following core technologies and frameworks:

NOTE: considering the impressive depth of the full article, we invite you to navigate to the original post to continue reading and access code snippets.


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