Thinking in GIS

In the last post I showed you a configuration for serving Ruby on Rails applications with Mongrel cluster and Apache in a *nix environment (Ubuntu). With this post I will reproduce the same configuration in a Windows environment.

The main difference in Windows is that you cannot use the mongrel_rails command with the cluster option (provided by the mongrel_cluster gem) that relies on daemonize functionality, only available on *nix platforms. What you will need to do is to manually create n Mongrel services for the n clusters you will need. Let's see how to do that.

Install Ruby, gems and then install Ruby on Rails:

sudo gem install rails --include-dependencies

Now download and install Apache 2.2 using, as the fastest way, the msi package.

Now enable the needed modules (url rewriting, proxy, proxy_balancer e proxy_http) by editing the httpd.conf file (under c:Apache_Software_FoundationApache2.2conf, if you installed Apache in its standard path). You just need to uncomment the following lines (remove the #):

LoadModule rewrite_module modules/mod_rewrite.so
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so
LoadModule proxy_http_module modules/mod_proxy_http.so

Install the mongrel and mongrel_service gems:

gem install mongrel (pick last version for win32)
gem install mongrel_service (pick last version for win32)

Now we will create a mongrel cluster of 2 windows services responding at http://127.0.0.1 on ports 3010, 3011 serving a rail application at the path c:wwwrormyapp that will be started from the windows system user. The two windows services will be respectively named mongrel_myapp1 and mongrel_myapp2. Open the command prompt and type:

mongrel_rails service::install -N mongrel_myapp1 -p 3010 -e production -c c:\www\ror\myapp
mongrel_rails service::install -N mongrel_myapp2 -p 3011 -e production -c c:\www\ror\myapp

Now open the windows services tool, make the 2 new services have an automatic startup type (so they will still be started when you reboot). Test if your application is now running at the two ports:

http://localhost:3010
http://localhost:3011

If everything is working fine, you are ready to place Apache in front of these 2 mongrel services, to manage the load balancing of you application.

The best way to configure Apache is to create a Virtual Host for your ROR application. First edit your httpd.conf file, and uncomment the following line:

# Virtual hosts

Include conf/extra/httpd-vhosts.conf

Now edit the httpd-vhosts.conf file, like this (keep the slashes in the *nix fashion!):

NameVirtualHost *:80

#Proxy balancer section (create one for each ruby app cluster)
<Proxy balancer://myapp_cluster>
  BalancerMember http://myapp:3010
  BalancerMember http://myapp:3011
</Proxy>
#Virtual host section (create one for each ruby app you need to publish)
<VirtualHost *:80>
  ServerName myapp
  DocumentRoot c:/www/ror/myapp/public/

<Directory c:/www/ror/myapp/public/ >
      Options Indexes FollowSymLinks MultiViews
      AllowOverride All
      Order allow,deny
      allow from all
  </Directory>
#log files
  ErrorLog /var/log/apache2/myapp_error.log
  # Possible values include: debug, info, notice, warn, error, crit,
  # alert, emerg.
  LogLevel warn
  CustomLog /var/log/apache2/myapp_access.log combined
#Rewrite stuff
   RewriteEngine On
# Check for maintenance file and redirect all requests
  RewriteCond %{DOCUMENT_ROOT}/system/maintenance.html -f
  RewriteCond %{SCRIPT_FILENAME} !maintenance.html
  RewriteRule ^.*$ /system/maintenance.html [L]
# Rewrite index to check for static
  RewriteRule ^/$ /index.html [QSA] 
# Rewrite to check for Rails cached page
  RewriteRule ^([^.]+)$ $1.html [QSA]
# Redirect all non-static requests to cluster
  RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_FILENAME} !-f
  RewriteRule ^/(.*)$ balancer://myapp_cluster%{REQUEST_URI} [P,QSA,L]
</VirtualHost>

Add your app as a host in hosts.file (in the c:WINNTsystem32driversetc folder):

127.0.0.1 localhost
127.0.0.1 myapp

Restart now Apache from the Windows services panel, and if everything is fine you should have your app served by Apache at the following url:

http://myapp