Rack full tutorial

Rack full tutorial

Overview Introduction

Currently, Clever Cloud supports Rack-based applications. Created in 2007, Rack has become the de-facto standard for ruby web applications and is used in many frameworks such as Ruby on Rails.

Configure your Rack based application

Mandatory configuration

To follow this tutorial, you will need:

  • Ruby >= 1.9.2 (w/ Rubygems)
  • Bundler (gem install bundler and you’re good to go!)
  • Your preferred editor
  • Git (for the deploy part)
To manage your gems and ruby versions, we recommend rbenv. If you use a system-wide installation of ruby, You will have to use sudo with the gem and bundle commands, or use arguments that will make gem and bundle install the gem in directories you have write-permissions in.

My application does not exists already

Create a Ruby + Rake application locally

Our demo for this tutorial is here: https://helloworld-rack-demo.cleverapps.io/.

You can also doing it manually by following these instructions:

mkdir helloworld-rack
cd helloworld-rack
touch hello.rb config.ru Gemfile ## or gems.rb

Inside hello.rb put the following:

class HelloWorld
  def call(env)
   [200, {"Content-Type" => "text/plain"}, ["Hello world!"]]

Inside the config.ru (That is, the main Rack entry-point) put:

require './hello'
run HelloWorld.new

The gems.rb or Gemfile file will contain our dependencies:

source 'https://rubygems.org'

gem 'rack', '~>1.5.1'

gem "puma", "~> 6.4"

We don’t need any more dependencies. The gems.rb or Gemfile is mandatory to deploy on Clever Cloud.

Do not forget to init an empty git repository with $ git init

Test your application locally

To test your application, just fetch the dependencies using bundler:

$ bundle install
Fetching gem metadata from https://rubygems.org/..........
Resolving dependencies...
Using rack (1.5.2)
Using puma (6.4.2)
Using bundler (1.3.5)
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.

And start your application:

$ bundle exec rackup
[2013-09-16 17:35:26] INFO  WEBrick 1.3.1
[2013-09-16 17:35:26] INFO  ruby 2.0.0 (2013-06-27) [x86_64-linux]
[2013-09-16 17:35:26] INFO  WEBrick::HTTPServer#start: pid=5656 port=9292

You can now test with your browser at localhost:9292.

You can now read My application already exists

My application already exists

Create an application on Clever Cloud

With the web console

Refer to Quickstart for more details on application creation via the console.

With the Clever Tools CLI

  1. Make sure you have clever-tools installed locally or follow our CLI getting started guide.
  2. In your code folder, do clever create --type <type> <app-name> --region <zone> --org <org> where :
    1. type is the type of technology you rely on
    2. app-name the name you want for your application,
    3. zone deployment zone (par for Paris and mtl for Montreal)
    4. org the organization ID the application will be created under.

Refer to clever create for more details on application creation with Clever Tools.

Setting up environment variables on Clever Cloud

With the Clever Cloud console

  1. Go to the Clever Cloud console, and find the app you want to fine tune under it’s organization.
  2. Find the Environment variables menu and select it.
  3. In this menu, you will see a form with VARIABLE_NAME and variable value fields.
  4. Fill them with the desired values then select Add.
  5. Don’t forget to “Update Changes” at the end of the menu.

With the Clever Tools CLI

  1. Make sure you have clever-tools installed locally. Refer to our CLI getting started.
  2. In your code folder, do clever env set <variable-name> <variable-value>

Refer to environment variables reference for more details on available environment variables on Clever Cloud.

You can of course create custom ones with the interface we just demonstrated, they will be available for your application.

Environment injection

Clever Cloud injects environment variables from your application settings as mentioned in setting up environment variables and is also injecting in your application production environment, those from your linked add-ons.

Custom build configurations

On Clever Cloud you can define some build configuration: like the app folder to deploy or the path to validate your application deployment is ready To do that follow the documentation here and add the environement variable you need.

To access environment variables from your code, just get them from the environment with ENV["MY_VARIABLE"].

Git Deployment on Clever Cloud

You need Git on your computer to deploy via this tool. Here is the official website of Git to get more information: git-scm.com

Setting up your remotes

  1. The “Information” page of your app gives you your Git deployment URL, it looks like this:

    1. git+ssh://git@push.clever-cloud.com/<your_app_id>.git
    2. Copy it in your clipboard
  2. Locally, under your code folder, type in git init to set up a new git repository or skip this step if you already have one

  3. Add the deploy URL with git remote add <name> <your-git-deployment-url>

  4. Add your files via git add <files path> and commit them via git commit -m <your commit message>

  5. Now push your application on Clever Cloud with git push <name> master

Refer to git deployments for more details.

Linking a database or any other add-on to your application

By linking an application to an add-on, the application has the add-on environment variables in its own environment by default.

On add-on creation

Many add-ons do exist on Clever Cloud: refer to the full list and check add-ons dedicated pages for full instructions.

During add-on creation, an Applications screen appears, with a list of your applications. You can toggle the button to Link and click next. If you finish the process of add-on creation, the application is automatically linked to it.

Add-on already exists

In the Clever Cloud console, under the Service Dependencies menu of your application, you can use the Link add-ons dropdown menu to select the name of the add-on you want to link and use the add button to finish the process.

You can also link another application from the same page in the Clever Cloud console, using the Link applications dropdown menu.

More configuration

Need more configuration? To run a script at the end of your deployment? To add your private SSH key to access private dependencies?

Go check the Common configuration page.

You may want to have an advanced usage of your application, in which case we recommend you to read the Administrate documentation section.

If you can’t find something or have a specific need like using a non supported version of a particular software, please reach out to the support.

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