Magic: Ruby 1.8.5 + 1.9.1/Rails/Sinatra and Lighttpd

Ladies and gentlemen, gather ‘round! The Great Panini is going to perform an incredible illusion before your very eyes! You will tell your grandchildren of this day and they will not believe you! Take pictures!

The Great Panini will start with a pre-steam machines era CentOS 4 server. He will install two versions of Ruby and they will coexist peacefully! He will then use the blazing fast Lighttpd server to proxy queries to various Ruby frameworks and he will even make it look easy!

Hrm…Sorry.
I am going to tell you how I quickly updated a couple servers with Ruby 1.9.1 and Lighttpd. And it will look easy because it is, in fact, easy.
This article’s aim is to be practical but I will explain as we go along.

The first thing I did was update CentOS to a more recent version. This could take a while but it’s always a good idea to keep a server software up-to-date so I’m sure that your already are almost there:

yum update

In my case, after a couple hours (oops), the update was complete and I rebooted the servers.

Ruby 1.8.5

That’s the easy part because it’s the version of Ruby that currently comes with CentOS. Therefore you can install it using yum:

yum install ruby ruby-devel ruby-irb ruby-rdoc ruby-ri

Ruby 1.9.1

Download the package from ruby-lang.org:

wget ftp://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.1-p0.tar.bz2  
tar zxvf ruby-1.9.1-p0.tar.bz2  
cd ruby-1.9.1-p0

The trick, here, is to give all 1.9.1 binaries a different name. Fortunately, configure offers an option for that:

./configure --program-suffix=19

Build and install:

make && make install

Rubygems

Get rubygems from Rubyforge:

wget http://rubyforge.org/frs/download.php/60718/rubygems-1.3.5.tgz  
tar zxvf rubygems-1.3.5.tgz  
cd rubygems-1.3.5

Note that we are now using our brand new 1.9.1 binaries:

ruby19 setup.rb

Now, make sure your gems are up to date:

gem19 update

Let’s see. We want to use two frameworks: Rails and Sinatra. Installing them could not be simpler:

gem19 install rails  
gem19 install sinatra

We will use thin to run our programs:

gem19 install thin

Let’s make sure that thin is run when the server boots up:

thin install

This will create /etc/init.d/thin which we can then link to the appropriate runlevels using chkconfig

We will, when creating Ruby applications, tell thin about the instances it needs to run. This will be done by adding yml files to /etc/thin/

I am going, in this article, to create these applications in /home/yourdirectory/. Of course, use your own directory.

Rails

Let’s create a Rails application:

rails myrailsapp

In the application’s config/ directory, let’s create our thin yml file ( thin_myrailsapp.yml )

chdir: /home/yourdirectory/myrailsapp  
address: 127.0.0.1  
port: 3000  
servers: 4  
max_conns: 1024  
timeout: 30  
max_persistent_conns: 512  
user: www  
group: www  
environment: development  
pid: tmp/pids/thin.pid  
log: log/thin.log  
daemonize: true

chdir tells thin where our document root is located. Rails serves documents from document root/public/
address is localhost because that’s what will be used when proxying through Lighttpd
servers is ‘4’ which means that four servers will be instantiated, starting at , i.e. 3000, 3001, 3002, 3003
User and group : I am using the same user and group that Lighttpd runs as for simplicity sake.

Let’s tell Lighttpd about this new application. Edit /etc/lighttpd/lighttpd.conf , or wherever your configuration file is:

$HTTP["host"] =~ "myrailsapp\.yourdomain\.com$" {  
        $HTTP["url"] =~ "^/((images|javascripts|stylesheets)/(.*)$)" {  
                server.document-root = /home/yourdirectory/myrailsapp/public"  
        }  
        proxy.balance = "fair"  
        proxy.server =  ("" =>  
                (  
                        ( "host" => "127.0.0.1", "port" => 3000 )  
                )  
        )  
}

I am using the “fair” load balancer because, as the default option, it tries to be…fair, obviously, and isn’t too greedy: it does not compute a hash for each url.

Let’s now tell thin about this application by simply creating a symbolic link in /etc/thin/ :

ln -s /home/yourdirectory/myrailsapp/config/thin_myrailsapp.yml /etc/thin/

Restart Lighttpd and start thin:

/etc/init.d/lighttpd restart && /etc/init.d/thin start

I know…supposedly I should be able to simply type ’lighttpd reload’ and it will reload its configuration files but that does not always seem to work.

Now, the fun stuff:

Go to http://myrailsapp.yourdomain.com:3000 and you should be greeted by Rail’s welcome page.

Now, go to http://myrailsapp.yourdomain.com and you should see the same page, except this time it was proxyied by Lighttpd.

Sinatra

Create your application; e.g. the ubiquitous “hi” application. Again in /home/yourdirectory/mysinatraapp , create hi.rb :

require 'rubygems'  
require 'sinatra'  
get '/' do  
    'Hello world! I love kittens.'  
end

Create a config/ subdirectory:

mkdir config && cd config

In the config/ directory, let’s create our thin yml file ( thin_mysinatraapp.yml )

rackup: /home/yourdirectory/mysinatraapp/config/mysinatraapp.ru  
chdir: /home/yourdirectory/mysinatraapp  
address: 127.0.0.1  
port: 4567  
servers: 4  
max_conns: 1024  
timeout: 30  
max_persistent_conns: 512  
user: www  
group: www  
environment: development  
pid: /home/yourdirectory/mysinatraapp/thin.pid  
log: /home/yourdirectory/mysinatraapp/thin.log  
daemonize: true

Starting at port 4567 because, by convention, it’s Sinatra’s default port when started standalone.

Notice the main difference? Sinatra will rely on rack for its setup, hence the ’ rackup ’ keyword.
Let’s create that rack file ( mysinatraapp.ru )

require 'sinatra'  
    
Sinatra::Application.default_options.merge!(  
    :run => false,  
    :env => :development  
)  
    
require 'hi.rb'  
run Sinatra.application

Do not forget Lighttpd:

$HTTP["host"] =~ "mysinatraapp\.yourdomain\.com$" {  
            proxy.balance = "fair"  
            proxy.server =  ("" =>  
                    (  
                            ( "host" => "127.0.0.1", "port" => 4567 )  
                            # room for more instances  
                    )  
            )  
}

Of course, if you know that some directories will be dedicated to static content you can also check for these directory names and have Lighttpd serve them statically, as shown in myrailsapp’s example.

Restart Lighttpd and thin:

/etc/init.d/lighttpd restart && killall -HUP thin

Test it:

Go to http://mysinatraapp.yourdomain.com:4567 and you should see the message returned by hi.rb.

Now, go to http://mysinatraapp.yourdomain.com and you should see the same page, except, again. it was proxyied by Lighttpd.

Conclusion

As I wrote earlier, this is easy and actually fairly straightforward. It some of this is not working for you, it is likely because I glossed over something I really shoudln’t have. Post a comment and describe your issue and I will gladly help.