Hands-On Microservices with Node.js: Build, test, and deploy robust microservices in JavaScript

Hands-On Microservices with Node.js

Build, test, and deploy robust microservices in JavaScript

Diogo Resende

BIRMINGHAM - MUMBAI

Hands-On Microservices with Node.js

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First published: June 2018

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Contributors

About the author

Diogo Resende is a developer with more than 15 years of experience. He has worked with Node.js almost from the beginning. His computer education and experience in many industries and telecommunication projects have given him a wide background knowledge of other architecture components and approaches that influence the overall performance of an application.

About the reviewer

Bruno Joseph D'mello works at Accion labs as a senior software developer. He has 6 years of experience in web application development, in domains such as entertainment, social media, enterprise, and IT services. Bruno follows Kaizen and enjoys the freedom of architecting new things on the web. He has also contributed some of his knowledge by authoring books such as Web Development in Node.js and MongoDB - Second Edition, What You Need to Know about Node.js, and JavaScript and JSON Essentials.

Thanks to my family for their patience and encouragement.

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Table of Contents

Title Page

Copyright and Credits

Hands-On Microservices with Node.js

PacktPub.com

Why subscribe?

PacktPub.com

Contributors

About the author

About the reviewer

Packt is searching for authors like you

Preface

Who this book is for

What this book covers

To get the most out of this book

Download the example code files

Conventions used

Get in touch

Reviews

The Age of Microservices

Introducing microservices

Introducing Node.js

Modules

Arrow functions

Classes

Promises and async/await

Spread and rest syntax

Default function parameters

Destructuring

Template literals

Advantages of using Node.js

Node.js Package Manager

Asynchronous I/O

Community

From monolith to microservices

Patterns of microservices

Decomposable

Autonomous

Scalable

Communicable

Disadvantages of microservices

Summary

Modules and Toolkits

Express

Micro

Seneca

Hydra

Summary

Building a Microservice

Using Express

Uploading images

Checking an image exists in the folder

Downloading images

Using route parameters

Generating thumbnails

Playing around with colors

Refactor routes

Manipulating images

Using Hydra

Using Seneca

Plugins

Summary

State and Security

State

Storing state

MySQL

RethinkDB

Redis

Conclusion

Security

Summary

Testing

Types of testing methodologies

Using frameworks

Integrating tests

Using chai

Adding code coverage

Covering all code

Mocking our services

Summary

Deploying Microservices

Using virtual machines

Using containers

Deploying using Docker

Creating images

Defining a Dockerfile

Managing containers

Cleaning containers

Deploying MySQL

Using Docker Compose

Mastering Docker Compose

Summary

Scaling, Sharding, and Replicating

Scaling your network

Replicating our microservice

Deploying to swarm

Creating services

Running our service

Sharding approach

Replicating approach

Sharding and replicating

Moving to Kubernetes

Deploying with Kubernetes

Summary

Cloud-Native Microservices

Preparing for cloud-native

Going cloud-native

Creating a new project

Deploying a database service

Creating a Kubernetes cluster

Creating our microservice

Deploying our microservice

Summary

Design Patterns

Choosing patterns

Architectural patterns

Front Controller

Layered

Service Locator

Observer

Publish-Subscribe

Using patterns

Planning your microservice

Obstacles when developing

Summary

Other Books You May Enjoy

Leave a review - let other readers know what you think

Preface

This book is an end-to-end guide on how to split your monolithic Node.js application into several microservices. We'll cover some of the toolkits available, such as Express, Hydra, and Seneca, and create a simple microservice. We'll introduce you to continuous integration using Mocha to add a test suite, we'll use chai to test the HTTP interface, and we'll use nyc to see the test coverage.

We'll cover the concept of containers and use Docker to make our first deployment. We'll then use other tools, such as Docker Swarm, to help us to scale our service. We'll see how to do the same using Kubernetes, both locally and be using Google Cloud Platform, always using the same minimal microservice architecture and with minimal changes to the code.

Who this book is for

The book is targeted at people who know the basics of Node.js and want to enter the world of microservices, get to know its advantages and techniques, and understand why it's so popular. It can also be useful for developers in other similar programming languages, such as Java or C#.

What this book covers

Chapter 1, Age of Microservices, covers the evolution of computing and how development has changed and shifted from paradigm to paradigm depending on processing capacity and user demand, ultimately resulting in the age of microservices.

Chapter 2, Modules and Toolkits, introduces you to some modules that help you create a microservice, detailing different approaches: from very raw and simple modules, such as Micro and Express, to full toolkits, such as Hydra and Seneca.

Chapter 3, Building a Microservice, covers the development of a simple microservice using the most common module, Express, with a very simple HTTP interface.

Chapter 4, State and Security, covers the development of our microservice: from using the server filesystem to moving to a more structured database service, such as MySQL.

Chapter 5, Testing, shows how to use Mocha and chai to add test coverage to our previous microservice.

Chapter 6, Deploying Microservices, introduces you to Docker and helps you create a container image to use to run our microservice.

Chapter 7, Scaling, Sharding, and Replicating, covers the concept of replication when using Docker Swarm and Kubernetes locally to scale our microservice.

Chapter 8, Cloud-Native Microservices, shows how to migrate our microservice from the local Kubernetes to Google Cloud Platform, as an example of a fully cloud-native microservice.

Chapter 9, Design Patterns, enumerates some of the most common architectural design patterns and reviews the continuous integration and deployment loop used throughout the book.

To get the most out of this book

You should have basic Node.js skills and be somewhat comfortable with the language. We will cover Docker and Kubernetes, and it can be helpful to know the concepts of containers—but it's not mandatory.

You need to have Node.js (and npm) installed. We recommend using the current stable version, but you're free to use a previous version if it's an LTS one, with possible adaptions. If you want to deploy Kubernetes locally, you'll need to install it later on.

Download the example code files

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The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Hands-On-Microservices-with-Node.js. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Conventions used

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CodeInText: Indicates code words in the text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: Arrow functions are a shorter expression function syntax without their own function scope, meaning this reference will point to the parent scope.

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  this.uptime = process.uptime();

  setTimeout(() => {

    console.log(this.uptime);

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npm init –y

npm install express –save

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The Age of Microservices

Decades ago, more specifically in 1974, Intel introduced 8080 to the world, which is an 8-bit processor with a 2 MHz clock speed and 64 KB of memory. This processor was used in Altair and began the revolution in personal computers.

It was sold pre-assembled or as a kit for hobbyists. It was the first computer to have enough power to actually be used for calculations. Even though it had some poor design choices and needed an engineering major to be able to use and program it, it started the spread of personal computers to the general public.

The technology evolved rapidly and the processor industry followed Moore's law, almost doubling speed every two years. Processors were still single core, with a low-efficiency ratio (power consumption per clock cycle). Because of this, servers usually did one specific job, called a service, like serving HTTP pages or managing a Lightweight Directory Access Protocol (LDAP) directory. Services were the monolith, with very few components, and were compiled altogether to be able to take the most out of the hardware processor and memory.

In the 90s, the internet was still only available for the few. Hypertext, based on HTML and HTTP, was in its infancy. Documents were simple and browsers developed language and protocol as they pleased. Competition for market share was ferocious between Internet Explorer and Netscape. The latter introduced JavaScript, which Microsoft copied as JScript:

Simple single-core servers

After the turn of the century, processor speed continued to increase, memory grew to generous sizes, and 32-bit became insufficient for allocating memory addresses. The all-new 64-bit architecture appeared and personal computer processors hit the 100 W consumption mark. Servers gained muscle and were able to handle different services. Developers still avoided breaking the service into parts. Interprocess communication was considered slow and services were kept in threads, inside a single process.

The internet was starting to become largely available. Telcos started offering triple play, which included the internet bundled with television and phone services. Cellphones became part of the revolution and the age of the smartphone began.

JSON appeared as a subset of the JavaScript language, although it's considered a language-independent data format. Some web services began to support the format.

The following is an example of servers with a couple of services running, but still having only one processor.

Powerful but single-core servers

Processor evolution then shifted. Instead of the increased speed that we were used to, processors started to appear with two cores, and then four cores. Eight cores followed, and it seemed the evolution of the computer would follow this path for some time.

This also meant a shift in architecture in the development paradigms. Relying on the system to take advantage of all processors is unwise. Services started to take advantage of this new layout and now it's common to see services having at least one processor per core. Just look at any web server or proxy, such as Apache or Nginx.

The