Rails%203%20In%20Action

408 CHAPTER 14 Deployment
Once Rails has done its thing, it sends the request
back up the chain, going through Passenger to nginx and
then finally back to the client as the response—most commonly
HTML but it could be anything, really.
When you launch rails server, the process looks like
figure 14.4.
In this example, there’s only one instance of your
application serving requests and so it’s going to be slower
than having the Passenger pool of them serving it. Additionally,
nginx is super quick at serving files (like your CSS
and JavaScript ones) and handles these requests itself,
without Rails knowing about it. When you run rails server, it serves every request,
and is definitely not web scale. nginx and Passenger are designed for speed and reliability,
and so you should feel pretty confident in using them.
Enough talk, let’s get into this! You’re going to install the passenger gem now, and
it’s nice enough to set up nginx for you too!
14.6.1 Installing Passenger
To install Passenger, as your user on the box (vagrant ssh, if Vagrant) you can run the
same gem install you’ve been running all this time:
gem install passenger
Once this gem is installed, install nginx and the Passenger module by running this
lovely command. The -i option “simulates initial login,” meaning that the RVM script
will run before this command, making it available:
sudo -i passenger-install-nginx-module
At the prompt, press 1 for the install process to download and compile nginx automatically.
When prompted for a directory (/opt/nginx), press Enter. This’ll be the directory
your server runs from. After this, nginx will be compiled and installed. This
process takes a minute or two, so go grab something to eat or drink, or stretch.
Once it’s done, you’re told that Passenger inserted some configuration for you;
wasn’t that nice of it?
The Nginx configuration file (/opt/nginx/conf/nginx.conf)
must contain the correct configuration options in order for Phusion Passenger
to function correctly.
This installer has already modified the configuration file for you! The
following configuration snippet was inserted:
http {
...
passenger_root /usr/local/rvm/gems/ruby-1.9.2-p180/gems/passenger-
3.0.4;
passenger_ruby /usr/local/rvm/wrappers/ruby-1.9.2-p180/ruby;
...
}
client
server
Figure 12.4 Simplified
client-server relationship