Ruby Enterprise Edition is a server-oriented friendly branch of Ruby which includes various enhancements. Although it should share more or less the same Ruby 1.8.6 behavior and be 100% compatible, you should never rely on assumptions when debugging your application.

Debugging an application running on Ruby Enterprise Edition can be a little tricky unless you don’t install Ruby Enterprise Edition on your local machine. However, this means you should either replace your favorite Ruby version or create a kind of switch to choose the Ruby interpreter you might want to use for that specific development session.

Taking this problem to an other level, many programmers started to have the same need as soon as they wanted to test their application against Ruby 1.8.x and Ruby 1.9. Fortunately, the solution already exists and it’s called multiruby.

Multiruby is an awesome tool crafted by Ryan Davis that enables you to run the same ruby code across multiple versions of ruby all at once. Off course, you can also run your application, debug your script or run your test against multiple ruby versions.

So, the next obvious step is to add Ruby Enterprise Edition to the list of multiruby versions. In this way you’ll be able to use Ruby EE on your local machine or execute the same piece of code with other Ruby interpreters.

Note. This tutorials assumes you are running a Unix based operating system like Linux or Mac OS X. This is my configuration:

• Mac OS X 10.5 Leopard
• ZenTest 4.1.1
• Ruby 1.8.6 (2008-08-11 patchlevel 287) [universal-darwin9.0]

Installing multiruby

If you haven’t heard about multiruby yet, you should probably start reading this excellent post by Dr Nic.

In short, follow these steps.

To install multiruby, first install the ZenTest GEM. It should add multiruby and multiruby_setup binaries as well.

Download, build and install the default multiruby Ruby versions. Simply type the following command to have multiruby do the job for you.

Please note that this step might take a while. Be patient while your computer downloads the .tgz archives and performs the necessary operations.

At the end of the story, multiruby should probably have installed 3 Ruby versions: Ruby 1.8.6, Ruby 1.8.7 and Ruby 1.9.1.

Run a simple command, for example multiruby -e "p 1+1", just to make sure everything works as expected. You should end up with something like this.

Great, it works! If you want to learn more about multiruby you should probably start reading multiruby and multiruby_setup documentation.

Installing Ruby Enterprise Edition

As you probably already noticed, you can add more Ruby versions using the multiruby_setup command. Unfortunately, you can’t actually use it to install Ruby Enterprise Edition because this version comes with a custom installer.

If you want to learn more about the problem, be sure to read the following section. Otherwise, simply skip to the Downloading Ruby Enterprise Edition section and you’ll find the steps to install Ruby EE without additional fuss.

Under the hood of multiruby

One of my biggest complain about multiruby is probably the lack of a good documentation. You can find many blog post and tutorial, but no comprehensive documentation neither about multiruby nor multiruby_setup.

What do you usually do when no documentation is available? Simple enough, you open the library and read the code!

I found the way multiruby detects ruby versions to be a bit obscure unless you are used to it. The are 4 subfolders in the .multiruby folder: tmp, build, versions and install.

All Ruby versions are located in the install subfolder and, if you store a new Ruby installation directly in this folder, it will be listed by the multiruby_setup list command. However, it turns out that if you try to run a command with multiruby, the version is simply ignored unless a corresponding .tar package exists in the versions folder.

And this is only a part of the story. The package in versions must be called ruby-CUSTOM_VERSION.tgz while the folder in install must be named exactly CUSTOM_VERSION. At least, this worked for me.

Be careful. Whenever you try to run a command with multiruby, it first compares the package in versions with the installed Ruby versions and if it founds a package without a corresponding folder in install, first it runs the installation process.

This is the reason why you should remove all Ruby Enterprise Edition installation files before running the very first script with multiruby.

Downloading Ruby Enterprise Edition

Download Ruby Enterprise Edition from Phusion website and move the package to the multiruby versions folder, usually located under your home directory at .multiruby/versions. Notice the . before the folder name: it’s a hidden folder, you might need to change your system settings to view it.

Move the package to the multiruby version folder and decompress it.

Running Ruby Enterprise Edition Installer

As I told you before, Ruby EE comes with its own installer. Run the script and answer the questions as follows.

The installer first checks your environment for required softwares. If a requirement is miss, the installation is aborted and you should install that library before running the installer again.

Once you have all dependencies installed, the installer asks for the target directory. This is the most important step of the entire tutorial: be sure to follow these instructions carefully.

The target folder must be called exactly as the ruby enterprise archive name, except for the ruby prefix that you must ignore. It should also points to the .multiruby/install folder.

Here’s the example for the package ruby-enterprise-1.8.6-20090610.tar.gz I’ve just downloaded before.

As you can see, I specified the full qualified path instead of using the ~ shortcut for the home directory: ~/.multiruby/install/enterprise-1.8.6-20090610.

Ok, you’re almost done. Now Ruby Enterprise Edition is going to be compiled and installed. As the installer notifies you, it’s going to take a while.
Relax and take a coffee.

Compilation Errors/Warnings

The installer doesn’t only install Ruby Enterprise Edition, but it also tries to install some common GEMs and libraries. Depending on your system configuration, you might be unable to get some of them.

For instance, Ruby Enterprise Edition hasn’t been able to install MySQL and PostgreSQL adapters on my computer due to the lack of some required libraries.

If this happens, don’t worry. Unless this is an unrecoverable error, the installer will simply skip them and you’ll be able to take care of these issues later, if you really need to.

If everything goes well, at the end of the installation you should probably see a message like

Removing Installation Files

Before running any multiruby command, you need to remove the installation files. Remove the Ruby Enterprise Edition folder but don’t remove the .tar package. multiruby needs it in order to work properly.

Checking multiruby installation

At this point, multiruby should correctly display Ruby EE in the known version list.

Run a simple test command with multiruby. It should be executed across all ruby versions, including Ruby EE.

Looking for other Ruby versions?

This tutorial is largely inspired by Nate Murray’s blog post about Adding MacRuby to multiruby. Checkout his tutorial to install MacRuby and don’t forget to read Rob Seaman’s blog post if you want to install JRuby.

Is this the right way to accomplish this?

If you dig into the multiruby source code, you probably notice that it provides built-in support for many different Ruby implementations. You might be wondering if this tutorial follows the right way to install Ruby EE.

As I told you at the beginning of this post, Ruby EE differs from the other Ruby versions because it comes with its own installer. You should use it to ensure the installation process ends successfully.

In order to add Ruby EE built-in support to multiruby, you should probably hack the Ruby EE installer and pass it the required parameters such as the target path. I must confess I didn’t have so much time to check how to do this and I found the default installation to be the most fast and easiest way.

Because multiruby is always looking for maintainers for others Ruby implementation, I don’t exclude to create a patch in the future. Off course, if you have a better solution, feel free to share it here and send a patch to the ZenTest project.

Related posts

1. Ruby has a new WHOIS library