Active Rails

The first thing we will need to install is a package called build-essential. This package includes a bunch of tools that will be used to install Ruby, and also by Ruby to compile C extensions. Without these tools, you won’t be able to install or let alone use Ruby.

To install these tools, run this command:

The second thing we will need to install is Git. This will be used for version control for your Rails application, and is also used to setup a tool called asdf in a little while.

We can install this with:

To verify that this has been installed, run:

You should see something like:

Next, we’ll need to install a tool that is used to manage the installation of different programming languages. We’re going to use this tool to install both the Ruby and Node.js programming languages.

To install Ruby using asdf, we first need to add the ruby plugin to asdf. Do that with this command:

Next, we can install Ruby by running:

asdf and its Ruby plugin knows where to get the source code for Ruby 2.7.1, and also what dependencies are needed to compile it.

Once it’s done all of that, it will start compiling Ruby, and you’ll see lots and lots of random output as checks a lot of things and then compiles all of the necessary files. There doesn’t appear to be an in-built way to silence this output, but you can just let it do its thing - go get a can of Diet Coke or something, it will take a few minutes.

When it’s done, you’ll see a nice happy:

So you now have a ruby installed. How do you use it? The folder it installed to isn’t part of your path, so calling ruby will have no effect.

We will need to set a current version of Ruby using asdf:

Now when we run ruby -v, we should see the current version of Ruby:

Next up, we will need to install Node.js. This is used by the Webpacker gem, which is a dependency of Rails. The webpacker gem uses a JavaScript package called Webpack to compile the JavaScript assets for your application.

To install Node, we’ll also use asdf. We first have to install the Node plugin:

And we have to run this command so that asdf can verify Node installation files:

Once those two steps are done, we can install Node:

Then we will need to configure asdf to use this version of Node:

To verify that this has been installed correctly, run node -v. You should see this:

So now you have a working Ruby. What about Rails?

Ruby comes with its own package manager called RubyGems, and this is what we can use to install Rails. Gems are just little bundled-up packages of Ruby code, and Rails is just a gem.

This will install the latest from the 6.0.x branch of Rails and all of its dependencies. Whatever version this installs will be fine for this book. It’ll take a while, as it figures out the dependencies, installs the gems, and then parses and installs documentation. (You can skip the documentation install by running the command with --no-document, eg. gem install rails --no-document. But hey, you might want it one day!)

When it’s done, verify the installation by running rails -v. The output will look something like this:

Hooray!

Once all that complicated setup is done, starting a new Rails app is trivial. Simply enter in your terminal:

Which will create a new app using SQLite, in the my_awesome_app directory of your current folder. This will also install Once that’s complete, you can start the Rails server:

Once Puma starts and tells you it has loaded on port 3000, you can open up a browser and visit http://localhost:3000.

You should see "Yay! You’re on Rails!"