Installing Ruby on Rails and PostgreSQL on Leopard

Setting up a development environment with Ruby on Rails and the PostgreSQL database on Leopard is straightforward. In an interesting twist, the hard part of setting up Rails and PostgreSQL on OS X 10.5 "Leopard" is easy with Linux, and the easy part is hard with Linux.

Rails, the Easy Part

If you haven't heard, Ruby on Rails is a web development framework created by David Heinemeier Hansson that uses the Model-View-Controller (MVC) design pattern for separating business logic from the presentation details. The MVC approach is very popular in enterprise class systems.

Apple recognized the momentum behind Rails and includes a basic configuration by default. The Ruby language (1.8.6) is installed along with the Rails (1.2.3) framework. In addition to the Ruby language and Rails, OS X Leopard includes a number of useful supporting packages (called Ruby Gems). This saves you the setup time for the basic infrastructure that is required on most Linux distributions.

PostgreSQL, the Hard Part

In order to get the PostgreSQL database up and running on Leopard, use MacPorts to install it. To use MacPorts, you first need to install the X-code tools from the Leopard DVD. It's an optional install, but you need the compiler and supporting libraries to compile and install PostgreSQL. (Most Linux distributions have precompiled PostgreSQL packages ready to install with one command, making this part of the set up easier on Linux.)

Once MacPorts is installed, install PostgreSQL with:

sudo port install postgresql83

It takes quite a while for MacPorts to download and compile PostgreSQL. It took about 90 minutes for me. After it's installed, there are a couple of post install commands that need to be run so that it starts automatically at boot time. The commands are described in detail once MacPorts finishes the basic installation.

Install the Ruby PostgreSQL Driver

In a production environment, you need the latest native PostgreSQL binary driver. I tried a couple of times to install the binary driver on my iBook, but I kept getting compile errors. I got around the problem by installing the "pure ruby" driver (indicated by the -pr suffix):

sudo gem install postgres-pr

I haven't noticed a performance issue during development, but I would not feel comfortable using it for a production application.

Telling Rails to Use PostgreSQL

The final step after starting a new Rails application is to modify the "config/database.yml" file to tell Rails to use PostgreSQL. Here is an example:

development:
  adapter: postgresql
  database: keithw
  username: keithw

Having Ruby and the basic Rails environment available out of the box is a huge plus for OS X Leopard.