Now that Ruby, Postgres, and Yarn are installed, we can setup a new project.
In Ruby, libraries of code that are packaged and distributed for everyone to use
are called gems. One way these gems can be installed is via the
which connects to the RubyGems repository to download
the library you are looking for. Rails is distributed as a gem and so we first
need to grab a copy of it from RubyGems.
It’s a good idea for us to synchronise our versions of Rails so there aren’t differences between the syntax I use and what Rails is expecting. Given that, the command is:
gem install rails -v 126.96.36.199
In the same way your application will depend upon Rails, Rails also depends upon
other gems. The
gem command knows this and will grab everything needed for
Rails to work.
While most gems are simply downloaded and installed, other gems will include code written in C. Gem developers might use C when they have specific performance requirements that justify the effort. Ruby is really fast but there are many tasks where the speed difference between C and Ruby matters. One example would be interacting with your database. It is vital that your database queries are blazingly fast and so you can expect those gems to have a lot of C code. You’ll notice the gems with C bindings because you’ll see “Building native extensions. This could take a while…”. Occasionally you’ll try to install a gem and you’ll find one of those little buggers will fail. Unfortunately, the errors are generally obscure and you just need to get good at finding the important line in the error message (even if you don’t understand it) and popping it into Google. You can be quite certain that you won’t be the first person to see the issue so don’t even bother trying to debug it yourself.
I’ve been following this tutorial in 2 completely new macOS virtual machines, one High Sierra and one Catalina, and I encountered an error when Bundler tried to install Puma. To get around that issue I ran:
bundle config build.puma --with-cflags="-Wno-error=implicit-function-declaration"
and then called
bundle again. If this doesn’t work for you, Google is your
Create the project#
Before creating your project, you’ll need to decide where you want this code to live on your computer. There is no right or wrong answer to this other than to say that your life will likely be made a lot easier if the answer is somewhere in your home directory.
In my case, I just put it in a folder called “dev” at the root level of home.
Using your terminal, you will want to change to this directory using
cd. In my
case, the command is:
~/ just means “in the home directory”. Since I’m on a Mac,
~/ is the
/Users/arice/ but it’s both less characters to type and also the same
across users and computers.
The command we’ll use to create the project directory is:
rails _188.8.131.52_ new cards_against_isolation \ --database=postgresql \ --skip-action-mailbox \ --skip-action-text \ --skip-active-storage \ --skip-turbolinks \ --skip-test \ --skip-system-test
While that is working away—it will take a bit if this is your first Rails app on this version of Ruby—let’s break down what that all means.
rails _184.108.40.206_: normally you wouldn’t see that second part. The
command automatically installs the latest version available, however, I want to
be sure we’re both on the same page so I’m explicitly telling it which version
new cards_against_isolation: create a new project called
--database=postgresql: set up Rails to use the PostgreSQL database. This will
pg gem in your application (we’ll discuss how this works soon).
If you are using MySQL, you can simply replace this with
By default, Rails will install all the available features. The approach is to make it as easy as possible to get started and then allow you to modify things as you learn more about it. Given this, we are turning off the features we won’t be using.
--skip-action-mailbox: Action Mailbox
allows Rails to accept and process incoming emails. While we will want to send
emails, we have no need to receive them.
--skip-action-text: Action Text
gives you text input fields that can allow rich text (think bold, italics,
bullet points, and links to websites). We only need people to enter basic
information like their names. The players are already going to be bold in their
actions, we don’t also need them to be bold in their typography.
--skip-active-storage: Active Storage
can be handy when you want people to be able to upload files.
--skip-turbolinks: Turbolinks is
an interesting tool for speeding up page loads. When a page change occurs
(for example, when someone clicks a link), instead of reloading the page,
wasn’t previously loaded. This can have huge performance implications because
those scripts and styles can take a bit of time for the browser to parse. On the
other hand, the fact that the page isn’t reloading causes “quirks” that you need
to account for. While Turbolinks provides plenty of ways to navigate these
concerns, I haven’t found the benefits to outweigh the costs in a small
application like this. I do have production applications using Turbolinks,
however, and in the right app it can give you some stunning results.
--skip-system-test: Rails uses Minitest as its testing
framework. There is nothing wrong with Minitest; it is beloved by many who argue
that the use of plain old Ruby code makes it is easy to learn. I have a strong
preference for Rspec which nudges you towards telling a story. For people new to
Ruby, it can be a little more work to understand but I believe testing in
narrative not only helps you think about what you are testing but, when reading
the tests, you can easily understand both what the application does and what is
being tested. We’ll add Rspec later.
Now, with everything installed, we need to change to the new directory:
One interesting thing to note is that the Rails install will add a file called
.ruby-version which contains nothing more than version of Ruby used to create
the project. As time progresses and you use newer versions of Ruby for newer
projects, this file will tell your Ruby environment manager to change version.
My global version of Ruby is 2.7.1 but, as soon as I
cd into this project,
rbenv automatically switches from 2.7.1 to 2.6.6.
MySQL installation error#
While this tutorial (and I) prefer PostgreSQL, I did test this process using MySQL and ran into the following issue:
linking shared-object mysql2/mysql2.bundle ld: library not found for -lssl clang: error: linker command failed with exit code 1 (use -v to see invocation)
The solution to errors while compiling native binaries is different depending on the very specific language of the error but, in this case, I solved the problem by running the following:
brew install openssl export LIBRARY_PATH=$LIBRARY_PATH:/usr/local/opt/openssl/lib/
Your first commit#
When building any application, there is no question you are going to make mistakes—I’ve never encountered a developer who has reached a state of enlightenment—and I expect to make mistakes in this build. To manage this known issue, we use a Version Control System (VCS) to keep track of our changes. These days, there is really only one VCS you need to know about, git. If you haven’t used git yet, I’d recommend you go and sign up for an account at GitHub now. Services like GitHub will store your code in the cloud. Any projects you allow to be public can be seen by anyone and can become part of your CV. A git repository also allows multiple people to work on the same project. You don’t actually need to store your code in the cloud—it’s absolutely possible to track your changes only on your computer—but if nothing else, it acts as a handy backup.
The Rails installer actually creates a new git repository for you; all you need to do is create your first “commit”. A commit saves your changes to the repository.
We’ll get into good git practices later but, for now, you first need to “stage” all the files for commit. Staging tells git which files (or changes in files) to store in the commit.
This stages every file in the current directory:
git add .
Next you need to create the commit and write a message explaining what you did. If you are new to git, you are going to want to make sure your shell knows to which editor you use. If you are not used to terminal editors like vim, you’re going to have a terrible shock when trying to write your commit message. Unfortunately, the solution to this problem varies by editor.
You can check if an editor is set by running:
and seeing if anything is returned. If you just get an empty line, you are going to want to set this.
If you are using VS Code, firstly make sure you have the
code shell command
installed. If you’ve ever typed “code” in your terminal, you have this. If not,
open the command palette (command-shift-p or View > Command Palette) and type
“shell”. One of the options will be to “Install ‘code’ command in PATH”.
Next, you can set VS Code as your editor by running:
CONFIG_FILE=`if [ $0 = "-bash" ]; then echo "$HOME/.bash_profile"; elif [ $0 = "-zsh" ]; then echo "$HOME/.zshrc"; else "Shell unknown"; fi` echo -e "\nexport EDITOR='code --wait'" >> "$CONFIG_FILE" . $CONFIG_FILE
should load the commit window in your editor ready for you to provide a message. You can think of the first line of a commit message as a subject while subsequent lines serve as the message body. You want your message to convey what changed but it’s more important to explain why the changes were made.
Given all we have done is install Rails for a personal game app, I think it’s acceptable to break the rules a little and simply write:
Make sure you save and close the commit window. You should expect commit messages to become more descriptive once we are making decisions that aren’t so stupendously mind-numbing.
Push to the repository#
Now is a great time to configure our git repository. If you don’t intend to save this code in the cloud you can skip this step but I would strongly recommend you push everything up.
Before pushing, we should change the name of our branch. By default, git will name your primary branch “master”. This terminology was inspired by enslavement and it best we move past it. Unfortunately, see language like this a lot in technology including master/slave database configurations and white/blacklists. Thankfully, it’s easy to change our branch name to “main”:
git branch -M main
Whether you use GitHub, Bitbucket, or another provider, the process of getting your code to the cloud is pretty much the same. First you need to create your new remote repository. This can be done via their web interface or many of the providers also have desktop apps.
You’ll need to give your remote repo a name. This will become part of the URL so
pick something meaningful. GitHub has suggested that, if I need inspiration,
furry-waddle might be a good option. While I appreciate this fine suggestion,
I’m going to stick with
cards-against-isolation. If you’d prefer to call yours
furry-waddle, that’s totally fine so long as it is meaningful to you.
You’ll probably be given 2 URLs, one HTTPS and one SSH. While HTTPS is the easiest to get started with, you’ll be forced to authenticate every time you want to push new code which is at least as annoying as it sounds. If you haven’t already added an SSH key to your version control provider, I’d recommend you go away and sort that out now. It’s a few minutes of pain for years of simplicity. Here are the GitHub instructions for macOS.
To add your remote repository URL to your project, run:
git remote add origin [your-url]
For example, my command is:
git remote add origin email@example.com:HashNotAdam/cards-against-isolation.git
This has now told git where to send the code but it is still necessary to point the current local branch to a branch on the remote repository. It is pretty much always the case that the name of your local branch is the same as the one on the remote (it’s super confusing if that isn’t true) but git still needs you to explicitly tell it that. Thankfully, you never need to remember the command to make that connection—while I’m sure I could remember it if I tried, I have no reason to try—just attempt to push your code and git will tell you what to do. If you run:
you will be told:
fatal: The current branch main has no upstream branch. To push the current branch and set the remote as upstream, use git push --set-upstream origin main
Not surprisingly, you can copy and paste that command. You only need to do this once per branch. When you are working with others, you should really be creating a new branch for every feature where a feature should (ideally) be small enough to complete within a day. For this, we will only use the main branch.
Once you’ve run that command, your code is safely in the cloud and we can start doing something substantial in the next post