Book Image

Building Enterprise JavaScript Applications

By : Daniel Li
Book Image

Building Enterprise JavaScript Applications

By: Daniel Li

Overview of this book

With the over-abundance of tools in the JavaScript ecosystem, it's easy to feel lost. Build tools, package managers, loaders, bundlers, linters, compilers, transpilers, typecheckers - how do you make sense of it all? In this book, we will build a simple API and React application from scratch. We begin by setting up our development environment using Git, yarn, Babel, and ESLint. Then, we will use Express, Elasticsearch and JSON Web Tokens (JWTs) to build a stateless API service. For the front-end, we will use React, Redux, and Webpack. A central theme in the book is maintaining code quality. As such, we will enforce a Test-Driven Development (TDD) process using Selenium, Cucumber, Mocha, Sinon, and Istanbul. As we progress through the book, the focus will shift towards automation and infrastructure. You will learn to work with Continuous Integration (CI) servers like Jenkins, deploying services inside Docker containers, and run them on Kubernetes. By following this book, you would gain the skills needed to build robust, production-ready applications.
Table of Contents (26 chapters)
Title Page
Copyright and Credits
Packt Upsell
Free Chapter
The Importance of Good Code

Mechanics of Docker

So, now that you understandwhy we need Docker, and, at a high level, how to work with Docker, let’s turn our attention to what a Docker container and image actually are.

What is a Docker container?

Docker is based on Linux Containers (LXC), a containerization technology built into Linux. LXC itself relies on two Linux kernel mechanisms –control groups and namespaces. So, let's briefly examine each one in more detail.

Control groups

Control groups (cgroups) separate processes by groups, and attach one or more subsystems to each group:

The subsystem can restrict the resource usage of each attached group. For example, we can place our application's process into the foo cgroup, attach the memory subsystem to it, and restrict our application to using, say, 50% of the host’s memory.

There are many different subsystems, each responsible for different types of resources, such as CPU, block I/O, and network bandwidth.


Namespaces package system resources, such as filesystems...