Book Image

Microservices with Clojure

By : Anuj Kumar
Book Image

Microservices with Clojure

By: Anuj Kumar

Overview of this book

The microservice architecture is sweeping the world as the de facto pattern with which to design and build scalable, easy-tomaintain web applications. This book will teach you common patterns and practices, and will show you how to apply these using the Clojure programming language. This book will teach you the fundamental concepts of architectural design and RESTful communication, and show you patterns that provide manageable code that is supportable in development and at scale in production. We will provide you with examples of how to put these concepts and patterns into practice with Clojure. This book will explain and illustrate, with practical examples, how teams of all sizes can start solving problems with microservices. You will learn the importance of writing code that is asynchronous and non-blocking and how Pedestal helps us do this. Later, the book explains how to build Reactive microservices in Clojure that adhere to the principles underlying the Reactive Manifesto. We finish off by showing you various ways to monitor, test, and secure your microservices. By the end, you will be fully capable of setting up, modifying, and deploying a microservice with Clojure and Pedestal.
Table of Contents (18 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
Index

Data management


In a microservices-based architecture, the data model and schema must not be shared among bounded contexts. Each microservice must implement its own data model backed by a database that is accessible only through the service endpoints. Microservices may also publish events that can be considered as a log of the changes the service applies to its isolated database. Keeping application data up to date across microservices may also add to the network overhead and data duplication.

Direct lookup

Although microservices have their own isolated persistence, an application implemented using microservices may need to share data among a set of services to perform tasks. In a monolithic environment, since there is a common database, it is easier to share data and maintain consistency using transactions. In a microservices environment, it is not recommended to provide direct access to the database managed by a service, as shown in the following diagram:

For example, when a user places a...