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

Configuration principles


All the application parameters that are related to the environment and affect the application state must be made configurable. For example, the connection string for a Datomic database that is used by Helping Hands services can be made configurable so that it can be updated externally to point to a specific instance of Datomic in production. Configuration parameters also make it possible to test the application in various environments. For example, if a Datomic connection string is made configurable for Helping Hands services, it can be used to test the services with an in-memory instance of Datomic in local development environments and later changed to point to the production instance of Datomic once they are deployed.

Defining configuration parameters

Applications must support multiple ways of defining the configuration parameters. Using command-line arguments is one of the most common ways of specifying the configuration parameters for the application. Environment...