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

Implementing event-driven patterns


Event-driven patterns address the observer model of communication to send messages among microservices. The messages are sent and received through a message broker that acts as a connecting bridge between the sender and the receiver. In a microservices architecture, these messages may be generated as events as an outcome of the action taken by the microservice. Messages for which the source microservice does not expect a response from the target service can be published as events asynchronously, instead of sending them over a REST API for direct communication. Since it is not a direct communication, an event can be published once and consumed by more than one microservice that has subscribed to receive it. Moreover, the sender does not get blocked by the receiver for each event that is published.

Message brokers also help to build a resilient architecture for event-driven communication as receivers need not be available while the event is being produced...