Deploy production with Capistrano

This article will describe how to deploy production with Capistrano. The official site provides useful explanations on the usage and structure of capistrano.

Here we assume that you are already able to login your production server with SSH key.

Installation

Add the lines to Gemfile:

Gemfile:

gem 'capistrano-rails', '1.1.2'
gem 'capistrano-rbenv', '2.0.3', require: false

Install and initialize capistrano:

bundle install
cap install

Add the followings lines to Capfile.

require 'capistrano/setup'
require 'capistrano/deploy'
require 'capistrano/rbenv'
require 'capistrano/bundler'
require 'capistrano/rails/migrations'
require 'capistrano/rails/assets'

Dir.glob('lib/capistrano/tasks/*.rake').each { |r| import r }

Configuration

Set up global configuration in config/deploy.rb as following sample.

config/deploy.rb:

# config valid only for current version of Capistrano
lock '3.4.0'

set :application, 'YOUR_APP_Name'
set :domain, "#{fetch(:application)}.com"
set :user, "deployer"
set :repo_url, "git@bitbucket.org:YOUR_ACCOUNT_NAME/#{fetch(:application)}.git"
set :deploy_to, "/home/deployer/apps/#{fetch(:application)}"
set :current_path, "#{fetch(:deploy_to)}/current"
set :shared_path, "#{fetch(:deploy_to)}/shared"
set :releases_path, "#{fetch(:deploy_to)}/releases"
set :default_env, { path: "~/.rbenv/shims:~/.rbenv/bin:$PATH" }
set :rbenv_ruby, '2.1.5'
set :deploy_via, :remote_cache

set :linked_files, fetch(:linked_files, []).push('config/application.yml', 'config/database.yml', 'config/secrets.yml')

set :linked_dirs, fetch(:linked_dirs, []).push('log', 'tmp')

Next, set up the IP of your production server in config/deploy/production.rb:

config/deploy/production.rb:

server '162.233.120.172', user: 'deployer', roles: %w{web app db}

Be sure that db is added for database migration will be executed.

Start to deploy

All you have to do is execute this command:

cap production deploy

List all tasks

To view all available tasks in capistrano:

cap -T

Define your own tasks

You can write your own tasks and put them under lib/capistrano/tasks/.

For example, assume we have wrote a task named access_check.rake with following content:

lib/capistrano/tasks/access_check.rake:

desc "Check that we can access everything"
task :check_write_permissions do
  on roles(:all) do |host|
    if test("[ -w #{fetch(:deploy_to)} ]")
      info "#{fetch(:deploy_to)} is writable on #{host}"
    else
      error "#{fetch(:deploy_to)} is not writable on #{host}"
    end
  end
end

Now, we can check if we have enough writing permissions on the production server by executing:

cap production check_write_permissions

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