CentOS Nginx Rails MySQL Ember

Setup a Rails and MySQL backend with an Ember frontend in a CentOS box using Nginx.

This guide was written using CentOS 6.5

MySQL

First we'll install MySQL and prepare it to be manipulated by rails with rake tasks.

sudo yum install mysql mysql-server mysql-devel
sudo /usr/bin/mysql_secure_installation
# answer yes to all

Start the MySQL console:

mysql -u root -p

Setup a database user for the rails app:

CREATE USER 'a_user_name'@'localhost' IDENTIFIED BY 'a_secure_password';
GRANT ALL PRIVILEGES ON a_database_name.* TO 'a_user_name'@'localhost';

Note that we didn't create a database, rails will take care of that when we use the rake tasks.

Ruby

We need to install a few dependencies for the ruby installation process.

sudo yum install git gcc make openssl-devel readline-devel

Once we have git, we'll install rbenv. If you don't want to install git in the server, you'll be fine if you just manually download a tar and extract it to the paths shown below.

# rbenv
git clone https://github.com/sstephenson/rbenv.git ~/.rbenv                      
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc                      
echo 'eval "$(rbenv init -)"' >> ~/.bashrc                         

# rbenv plugin
# allows us build ruby from source with one command
git clone https://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build

Actually install ruby:

CONFIGURE_OPTS="--disable-install-rdoc" rbenv install 2.2.2

Set the default ruby version for the user account

rbenv global 2.2.2

Rails

Before installing any gems we'll set a configuration that will disable the installation of gem's documentation. The assumption is that we are working with an actual server, so we don't need any of those files. We also gain a bump on speed and reduced memory usage during installation, helpful for small servers.

echo 'gem: --no-document' >> ~/.gemrc

Now we'll install our first gems.

gem install rails -v 4.2.1
gem install bundler

Rails app

I trust you know what to do here, install and start the rails app. Brief reminder:

bundle install
rake db:create
rake db:migrate
# rake db:seed 
# or
# load DB backup

And start the app. There are many ways of doing this (webrick, unicorn, etc). Just remember the port number where the app is running, we'll use it in the Nginx configuration.

Nginx

From the Nginx site download the repo configuration package for CentOS 6, we'll use it to configure a new repository and then install Nginx from there.

sudo yum install nginx-release-centos-6-0.el6.ngx.noarch.rpm
sudo yum install nginx

Configure the routes for the rails and ember app, you'll need sudo privileges to edit the configuration files.

In /etc/nginx/nginx.conf add:

# Its important to use the same user as the one that will be executing the app
# Doing so saves you the trouble of dealing with folders permissions
user current_user; 

# ...nginx settings...

http {

  # ...http settings...

  upstream my_rails_app {
    # use the correct port here
    server 127.0.0.1:3000_maybe_8080;
  }
}

For the following configuration it is assummed that the rails app and the ember files share the same root folder. Like this:

tree web-app/
web-app/
├── ember
└── rails

In /etc/nginx/conf.d/default.conf add:

server {

  location / {
    root /home/current_user/web-app/ember;
    try_files $uri /index.html?/$request_uri;
  }

  location /api {
    try_files /fake_file_default_to_rails @rails;
  }

  location ~* ^.+\.(jpg|jpeg|gif|png|ico|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|txt|tar|mid|midi|wav|bmp|rtf|mp3|flv|mpeg|avi|woff)$ {
    root /home/current_user/web-app;
    # headers and other settings
    try_files $uri /ember/$uri /rails/public/$uri @rails;
  }

  location ~* \.(?:css|js)$ {
    root /home/current_user/web-app;
    # headers and other settings
    try_files $uri /ember/$uri /rails/public/$uri @rails;
  }

  location @rails {
    proxy_set_header  X-Real-IP       $remote_addr;
    proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header  Host            $http_host;
    proxy_redirect    off;
    proxy_pass http://my_rails_app;
  }
}

Many of the settings for both files were left out because those will vary a lot between applications. I show what is essential for the routing of rails and ember requests.

Time to reload Nginx with the new configuration.

sudo service nginx reload

Now you can visit your site in the browser. If its not working properly, review the log files located in /var/log/nginx/.

# example
tail -f /var/log/nginx/error.log

We are done.

Possible errors

If you stumble in the logs with something like:

failed (13: Permission denied)

You might want to check if SELinux is getting in the way. It is known that there are certain scenarios where SELinux will block Nginx if an explicit policy is not configured.


Gastón I. Silva