Deploy Ruby based apps

This page takes you through setting up instellar on a Ruby on Rails application. You will learn how to configure your application to run on your PaaS

Example Application

We’ve created an example application incase you wish to skip and go straight to the source code.

instellar.yml

This file is used to describe to PAKman how to build your application. The following is taken from a Ruby on Rails based application. This configuration will change depending on your application. This file will work with a freshly generated rails app.

Dependencies

The dependencies section enables you to define OS packages for your application. This list may grow if your application depends on more OS level packages.

dependencies:
  build:
    - ruby
    - ruby-bundler
    - ruby-dev
    - ruby-tzinfo
    - libpq-dev
  runtime:
    - bash
    - curl
    - jq
    - ca-certificates
    - s6
    - ruby
    - ruby-bundler
    - ruby-tzinfo
    - ruby-rdoc
    - libpq
    - locomo-openrc

Choosing a Stack

We’re using alpine as the base image for all the containers that run the applications. We recommend using alpine/3.17 for all applications. However please check the alpine packages listing to see compatibility for your language and framework. In this case alpine/3.17 will run ruby 3.1.4.

You can choose from the following:

• alpine/edge
• alpine/3.17
• alpine/3.16
• alpine/3.15

stack: alpine/3.17

Build

The below section tells PAKman how to actually build your application. In this case we’re just setting the bundle config for deployment, running bundle install and compile assets. As you can see it’s pretty straight forward.

build:
  destinations: 
    - '*'
    - .bundle
  command: |
    bundle config set deployment 'true'
    bundle config set without 'development test'
    
    bundle install
    
    bundle exec rails assets:precompile

Run

The below section explains how your application is run. You can see we have the ability to define commands. These are commands you wish to run like migrations or seeds if you have them.

The services section enables you to define how your application is run. How does it start? How does it stop? In this case we’re using the kill pid. By default rails server creates pid file in the tmp/pids directory.

If you want to run workers you can define that as a separate service offered by your application. In this case the resulting worker will be started with bundle exec sidekiq -C config/sidekiq.yml

run: 
  name: locomo
  commands: 
  - name: migrate
    binary: rails
    call: db:migrate
  services:
  - name: web
    binary: rails
    start: 
      call: server
    stop:
      kill: true
      pid_path: tmp/pids/server.pid
  - name: worker
    binary: bundle
    start:
      call: 'exec sidekiq -C config/sidekiq.yml'

Hooks

These are the lifecycle of the alpine packages. You can define their behaviour. Generally we don’t expect this to change from app to app. However feel free to adjust as required.

In this case rc-update add locomo will add our locomo app to the default run. This will ensure our app automatically starts when the container is restarted (incase it needs to restart).

The rc-service locomo migrate will run the migration. In this case it will run after the package is installed and after the upgrade.

• rc-service locomo start will start the application
• rc-service locomo stop will simply stop the application

Your application will be built into openrc and supervised by the s6 supervisor suite.

hook:
  post-install: |
    rc-update add locomo
    rc-service locomo migrate
  pre-upgrade: |
    rc-service locomo stop
  post-upgrade: |
    rc-service locomo migrate
    rc-service locomo start
  post-deinstall: |
    rc-service locomo stop
    rc-update locomo rdio

Putting it Together

The final file looks like the following:

dependencies:
  build:
    - ruby
    - ruby-bundler
    - ruby-dev
    - ruby-tzinfo
    - libpq-dev
  runtime:
    - bash
    - curl
    - jq
    - ca-certificates
    - s6
    - ruby
    - ruby-bundler
    - ruby-tzinfo
    - ruby-rdoc
    - libpq
    - locomo-openrc

stack: alpine/3.17

build:
  destinations: 
    - '*'
    - .bundle
  command: |
    bundle config set deployment 'true'
    bundle config set without 'development test'
    
    bundle install
    
    bundle exec rails assets:precompile

run: 
  name: locomo
  commands: 
  - name: migrate
    binary: rails
    call: db:migrate
  services:
  - name: web
    binary: rails
    start: 
      call: server
  - name: worker
    binary: bundle
    start:
      call: 'exec sidekiq -C config/sidekiq.yml'

hook:
  post-install: |
    rc-update add locomo
    rc-service locomo migrate

  pre-upgrade: |
    rc-service locomo stop

  post-upgrade: |
    rc-service locomo migrate
    rc-service locomo start

  post-deinstall: |
    rc-service locomo stop
    rc-update locomo rdio