Ruby

Warning

All the following should be done as your chosen user - scheduler - not as root.

If you are still logged in as root (your command line prompt is a # symbol) then log out now and log back in as scheduler. You’ll note that your command line prompt changes to a $ symbol.

Ruby Version Manager (RVM)

In order to make sure we are using a compatible set of packages, we use the Ruby Version Manager (RVM) to install and manage them.

By using RVM, one can have multiple copies of Ruby, Rails and supporting packages installed on the same machine, and be sure of always using exactly the one intended.

You will find instructions for installing RVM on the page referenced above, but in essence it comes down to just two commands.

$ gpg --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB
$ \curl -sSL https://get.rvm.io | bash -s stable

This incidentally is why you installed curl in the previous step.

Note

It is just possible that the gpg command above will fail, apparently due to a compatibility problem between dirmngr and some DNS servers. It’s not a common occurence, but it has been known to happen. If it happens to you, there is a workaround.

$ echo "standard-resolver" >>~/.gnupg/dirmngr.conf
$ killall dirmngr

and then try again.

Once the installation has completed, log out and then back in again in order to pick up your modified environment.

Note

If you are doing all this not on a headless server but on a workstation with the default Debian Gnome desktop, there’s one little extra wrinkle.

To get rvm to work properly you need to edit your terminal preferences and under the “Command” tab, tick “Run command as a login shell”. If you don’t do that then rvm doesn’t get to initialize itself properly when you start up an interactive terminal.

Ruby

The application currently uses Ruby version 2.6.6. Ruby 2.7 has been released but there are some deprecations within it which clash with Rails 5. Rails 5 applications will run with Ruby 2.7, but produce warnings as a result of these deprecations.

To install the necessary Ruby, use the following command. It can take a few minutes to complete, depending on the speed of your processor.

$ rvm install ruby-2.6.6

You will be prompted for your user’s password (not the root password) in order to install extra required operating system packages.