Learn Chai, Dart and Docker

While "It works on my computer" might give you an excuse to close a bug ticket in the backlog, it doesn't really work when you're working on a team.

You need to ensure that your application can run regardless of what hardware your teammates are running or libraries they have installed.

Docker solves this problem by collecting everything your application needs to run into a container.

Containers aren't just for source code. They can hold configuration, scripts, and even their own filesystem. It's similar to a Virtual Machine, without having to bring a full operating system along for the ride.

Because containers run in isolation, there is some configuration involved to allow for files to be saved and containers to communicate with one another.

One of the most useful ways to get your head around Docker is to see it in action.

Follow along with Joel Lord as he works through the process of preparing an application to run in separate containers for the frontend and backend of an application that searches for gifs and re-encodes them with a caption supplied by the user.

You'll see how to configure the separate containers to communicate with one another, work with environment variables, and persist data to your local machine. Along the way, you'll pick up some tips on useful commands and bash scripting. Finally, you'll learn how to use Docker Compose to make it easy to run multiple containers simultaneously.


Docker containers wrap a piece of software in a complete filesystem that contains everything needed to run: code, runtime, system tools, system libraries – anything that can be installed on a server. This guarantees that the software will always run the same, regardless of its environment.

docker

Containerize Full-Stack JavaScript Applications with Docker

Docker Fundamentals

Dart is an object-oriented language you can use for building web applications, server-side code, and even mobile apps. It’s expressive, powerful, and has a friendly learning curve. 

In this course, we will look at the syntax and semantics of the Dart programming language. We will also cover various aspects of the Dart ecosystem, including its tools and packages that help make you a productive developer. This knowledge is applicable when developing software for client, server, and especially mobile with the Flutter framework. 

This course is beginner-friendly, but is well-suited for experience programmers as well. 

Dart is an open-source, scalable programming language, with robust libraries and runtimes, for building web, server, and mobile apps.

dart

Get Started with Dart

In this course we will take a simple Node.js app that connects to a MongoDB database and uses an Express web server, and learn how to setup a full software development deployment process as well as how to properly “Dockerize” the app. 

We’ll step through setting up proper version control techniques, managing configuring within the environment, setting up proper build/deploy/run processes, and all with abiding by Docker best practices. We’ll also make sure our deployment is setup for scale, and have consistent development practices in place for reliable app deployments.

Build a Twelve-Factor Node.js App with Docker

Docker containers are stateless by default. In order to persist filesystem changes, you must use docker volumes. In this lesson, we will go over how to copy files over to Docker containers, how to create volumes and copy data to them, and also how to mount remote folders for persisting updates.

Create Docker Volumes for Persistent Storage

In this lesson we will cover proper version tagging when building Docker images, creating a docker-compose.yml file for proper release management, and running the tagged release by using Docker Compose to launch app resources as Docker containers.

Build, Release and Run Containers with Docker Compose

NGINX is a free, open-source, high-performance HTTP server and reverse proxy, as well as an IMAP/POP3 proxy server. 

nginx

Learn about the concepts of managing data within Docker volumes, including all of the commands to create and manage volumes. We'll demonstrate how to mount a Docker volume to one or many containers by creating and mounting a volume to an Nginx proxy, and then verify the output with curl. You'll also see how changes to files within volumes of one container propagate to other containers with the same volume mounted, and learn various commands to inspect Docker volumes.

Manage Data within Docker Volumes

In this lesson we will cover how to build your own custom Docker image from scratch. We'll walk through the process of starting a Debian container, installing packages and working through configuration issues, as well as a strategy for building a Dockerfile.

Build Your Own Custom Docker Image

In this lesson, we will look at `docker container prune` to remove old docker containers. We can also use `docker system prune` to clean up any containers, images, volumes, and networks all in one command.

Prune Old Unused Docker Containers and Images

In this lesson, we'll find out the basics of running Docker containers. We'll go over how to download images from Docker Hub, what happens when you stop containers, how to restart a container once it's been stopped, and also how to remove containers.

Run, Stop and Remove Docker Containers

Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.

chai

Every dependable library needs to have tests to ensure that you don't push accidental bugs. In this lesson, see how you can set up mocha and chai to start testing your library.

Setting up Unit Testing with Mocha and Chai

Learn how to build a simple Node.js web server with Docker. In this lesson, we'll create a Dockerfile for a simple Node.js script, copy and build it into a Docker image, and start a container to run the web server.

Build a Simple Node.js Web Server with Docker

Now that you've got everything set up with mocha and chai, it's time to actually write tests. In this lesson you'll learn how to use `describe` and `it` to outline your tests and make sure you don't break your library in the future.

Unit Testing with Mocha and Chai

In this lesson, we will use Chai's request method to test our Node application's API responses.
By the end of this lesson, you will know how to:
- install the prerequisites to use mocha and chai in your application
- test for HTTP status response codes
- test for a string of text on a page
- test for a json response and validate the properties of the object
- write tests that not only verify the response of your application, but the behavior as well


Test Node RESTful API with Mocha and Chai

Learn the benefits of running one-off, short-lived Docker containers. Short-Lived containers are useful to execute one-line commands or setup scheduled tasks. We'll demonstrate setting up a cronjob from the host machine to tap into the benefits of running automated, timed scripts with Docker.

Run Short-Lived Docker Containers

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. Mocha tests run serially, allowing for flexible and accurate reporting, while mapping uncaught exceptions to the correct test cases.

mocha

Writing great ES6 style Promises for Node.js is only half the battle. Your great modules must include tests as well to ensure future iterations don't break them. In this lesson, I show you a simple ES6 Promise in Node.js, then walk you through creating tests in Mocha using chai and chai-as-promised to test both resolve and reject methods.

Testing ES6 Promises in Node.js using Mocha and Chai

Learn how to setup an Nginx proxy server with Docker that sits in front of a Node.js app. You can use a proxy to control the flow of frontend requests hitting your app, as well as to achieve better performance and scalability. We'll create a sample Node.js app, configure a default Nginx configuration file for proxying web requests, build both Node.js and Nginx Docker images, and learn how to link everything up and get it running with Docker specifics.

Setup an Nginx Proxy for a Node.js App with Docker

In this lesson, you will learn how to verify your API server is returning HTTP 400 responses when clients submit incorrect data. Returning HTTP 400 ensures that your clients are notified of the incorrect usage. Testing for them ensures your API returns errors instead of incorrect responses when supplied with incorrect data.

Test for HTTP 400 responses with Mocha and Chai

Learn the basics of downloading and pulling Docker images from Docker Hub. Learn the difference between default tags and version specific tags. Also learn how to display all images, and different ways to remove images.

Download and Remove Docker Images

Docker containers should be designed to be stateless, meaning that they can survive system reboots and container terminations gracefully, and without the loss of data. Designing with stateless containers in mind will also help your app grow and make future horizontal scaling trivial. 

In this lesson, we will review an app that saves uploaded files to the filesystem. Then we will learn how to setup a persistent volume for the uploaded files so they can survive Docker container halts, restarts, stops and respawns.

Run Stateless Docker Containers

By default, Docker is locked down and no ports are exposed. We’ll cover how to expose ports when building your image with a `Dockerfile`, and how to export that port as a service when running containers. 

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