====== Ruby instance family ======
The Ruby instance family on Simple Hosting is a perfect solution to host web applications.
You can publish any web application that uses Rack, including Ruby On Rails and Sinatra applications, coupled with the database of your choice.
The extensible storage space and multiple sizes make it easy and affordable to get started and grow your application over time.
===== Prerequisites =====
Users of Ruby Simple Hosting instances should have:
* some knowledge of the Ruby language
* some knowledge of git
* an application which is compatible with Ruby 2.4 (MRI) or 1.9.3 in old instances
* an application which is compatible with [[http://rack.github.io/|Rack]]
* an application which uses [[http://bundler.io/|Bundler]] to manage dependencies
* the following installed locally:
* ruby
* bundler
* git
Note: Usage of the Ruby instance is dependent on standard tools such as bundler and git being installed locally.
===== Directory structure =====
To be compatible with Rack, your application's files must adhere to a specific layout, containing the following directories and files:
* ''config.ru'': A Rackup file like the one specified in the [[http://rack.rubyforge.org/doc/SPEC.html|Rack documentation]]
* ''public/'': If you have any static files, they should be in this directory
Ruby on Rails applications (rails >2) should work out of the box.
Example file structure:
.
├── config.ru
└── public
└── robots.txt
===== Installation of dependencies =====
In order for your Ruby application's dependencies to be installed, you must declare them in a //Gemfile// placed at the root of your project. This file must match the format indicated in [[http://bundler.io/v1.5/man/gemfile.5.html|the Bundler documentation]].
Example Gemfile:
source 'https://rubygems.org'
gem 'rails', '~> 4.0.0'
gem 'debugger', group: :development
Note: During the installation of dependencies, the gems specified in the ''development'' and ''test'' groups will not be installed.
==== bundle install ====
Once your dependencies have been declared, you must generate a ''Gemfile.lock'' file by running the ''bundle install'' command. This is the file that will be used to install the dependencies on your instance.
===== Configuring Multiple Vhosts =====
If you would like for multiple vhosts to route to different Ruby applications on a single Simple Hosting instance, then you will need to configure the routing in the config.ru file.
A simple config.ru example below:
map 'http://www.example.com/' do
run Proc.new { |env|
[200, {'Content-Type' => 'text/html; charset="utf-8"'},
['It works',
"It works!
You've reached ",
'www.example.com'
]
]
}
end
map 'http://www.another-example.com/' do
run Proc.new { |env|
[200, {'Content-Type' => 'text/html; charset="utf-8"'},
['It works',
"It works!
You've reached ",
'www.another-example.com'
]
]
}
end
===== Databases =====
Like the other Simple Hosting instance families, Ruby instances support three types of databases: MySQL, PostgreSQL and MongoDB.
==== PostgreSQL ====
Parameters:
* Hostname: **localhost**
* Port: **5432**
Here's an example Ruby on Rails configuration with a PostreSQL database (''config/database.yml''):
production:
adapter: postgresql
database: ruby-example
host: localhost
port: 5432
username: hosting-db
password:
encoding: unicode
pool: 5
==== MySQL ====
Parameters:
* Socket : **/srv/run/mysqld/mysqld.sock**
Here's an example Ruby on Rails configuration with a MySQL database (''config/database.yml''):
production:
adapter: mysql2
database: ruby-example
socket: /srv/run/mysqld/mysqld.sock
username: tony
password: micelli
encoding: utf-8
pool: 5
==== MongoDB ====
Parameters:
* Hostname: **localhost**
* Port: **27017**
Here's an example Mongoid configuration (''mongoid.yml''):
production:
sessions:
default:
database: ruby-example
hosts:
- localhost:27017
===== Pushing your application to your instance =====
You must use git to push your application to your instance and to deploy it.
==== Create a local git repository ====
First, in the root directory of your project on your local machine, run the following commands to initialize a Git repo to track your code's changes:
$ git init
$ git add .
$ git commit -m "Initial commit"
==== Deployment of your application ====
You can find the instance ID, datacenter ID and URL of your instance's git repo on your instance's control panel in your Gandi account.
Once your code is tracked by git locally, you must push it to your instance.
In the command below, replace ''INSTANCE_ID'' with your instance ID, and and ''DC_ID'' with the ID of the datacenter where your instance lives (''dc0'' for Paris, ''dc1'' for Baltimore, ''dc2'' for Luxembourg):
$ git remote add gandi git+ssh://INSTANCE_ID@git.DC_ID.gpaas.net/default.git
$ git push gandi master
Then, run the deploy command:
$ ssh INSTANCE_ID@git.DC_ID.gpaas.net deploy default.git
To deploy a particular branch or tag (a //production// branch, for example), just specify it as a second argument:
$ ssh INSTANCE_ID@git.DC_ID.gpaas.net deploy default.git production
===== Logs and troubleshooting =====
Standard output (stdout) as well as errors related to the application's execution are stored in the following logfiles on your instance's data disk:
* via SSH: ''/srv/data/var/log/www/uwsgi.log''
* via SFTP: ''/lamp0/var/log/www/uwsgi.log''
This is useful, notably, for verifying that your application has started correctly.
===== Cron jobs =====
Like other Simple Hosting instance families, it's possible to run scheduled tasks (cron jobs) on Ruby instances. Environment variables defined by your application are also available in your cron jobs (see [[#internal_design|internal_design]] for more details on environment variables).
Example cron job:
1@hourly 0 test (cd /srv/data/web/vhosts/default; rake my_namespace:some_useful_task)
For more information on cron jobs and Simple Hosting, see [[http://wiki.gandi.net/en/simple/anacron]].
===== Internal design =====
Ruby instances use [[http://uwsgi-docs.readthedocs.org/en/latest/|Uwsgi]] to execute your application's code. [[http://httpd.apache.org/|Apache]] is used to serve static files. Apache will serve the files that exist in a directory named ''public/'' at the root of your project and will relay all other requests to Uwsgi.
The following environment variables are assigned and available in your application and in cron jobs:
* RAILS_ENV=production
* RACK_ENV=production
===== Additional information =====
**Redis** is not currently supported on Simple Hosting. If you'd like to see redis support, let us know on our [[https://www.gandi.net/hosting/simple/wishlist/|wishlist]].