Capistrano 3 has been rebuilt from the ground up. Learn how to transition from using Capistrano version 2 to Capistrano version 3.

1. Capistrano 3
Deployment
Creston Jamison
RubyTree Software, Inc.

2. What is Capistrano?
 A remote server automation and deployment
tool.
 Version 2 is mostly Rails specific and used a
custom DSL.
 Version 3 is re-written from the ground up
and is trying to be more agnostic.
 Version 3 uses Rake with methods included to
easily run tasks “on” servers.

3. Breaking It Up
 capistrano
 capistrano-rails
 capistrano-bundler
 capistrano-rbenv / rvm / chruby

4. Nice
 In general, less configuration to deploy rails.
 Multi-Stage by default
 Easily sym link files and folders (e.g.,
config/database.yml, log)
 Rails: database migrations automatically run
during deploy
 Deployments have more granularity for
defining when tasks occur
 Easily setup parallelism for tasks.

5. Where does my config go???
 Version 2
 Gemfile -> only capistrano
 Capfile -> no changes
 config/deploy.rb -> all configuration
 Version 3
 Gemfile -> capistrano + others
 Capfile -> require dependencies
 config/deploy.rb -> shared configuration (set)
 config/deploy/[env].rb -> server role configuration
 lib/capistrano/tasks -> Rake files for tasks

6. Gemfile
group :development do
gem 'capistrano-rails', '~> 1.1'
end

7. Run
bundle
bundle exec cap install
 Setup public key authentication to log in as
deploy_user.

8. Cap file
require 'capistrano/deploy'
require 'capistrano/rails'
# require 'capistrano/rvm'
# require 'capistrano/rbenv'
# require 'capistrano/chruby'
# require 'capistrano/bundler'
# require 'capistrano/rails/assets'
# require 'capistrano/rails/migrations'

9. config/deploy.rb
set :application, 'test_deploy'
set :repo_url,
'git@github.com:username/test_deploy.git'
set :deploy_to,
'/my/server/directory/test_deploy'

10. config/deploy.rb, part 2
set :user, 'deploy_username'
set :linked_files, %w{config/database.yml}
set :linked_dirs, %w{bin log tmp/pids tmp/cache
tmp/sockets vendor/bundle}

11. config/deploy.rb, part 3
namespace :deploy do
desc 'Restart application'
task :restart do
on roles(:app), in: :sequence, wait: 5 do
# execute :touch, release_path.join('tmp/restart.txt')
end
end
after :publishing, :restart
end

12. config/deploy/production.rb
role :app, %w{deploy_user@ip_address:port}
role :web, %w{deploy_user@ip_address:port}
role :db, %w{deploy_user@ip_address:port}
OR
server ‘ip_address', user: ‘deploy_user', roles:
%w{web app db}, ssh_options: { port: port }

13. Task Example
desc 'Create a new sitemap'
task :create_sitemap do
on roles(:app) do
within release_path do
with rails_env: fetch(:stage) do
execute :rake, ‘sitemap:create’
end
end
end
end
after :finished, :create_sitemap

14. Deploying
 Ensure your web (apache, nginx) and app (unicorn,
puma, passenger) are configured.
 bundle exec cap production git:check
 bundle exec cap production deploy:check
 Create ~/shared/config/database.yml
 bundle exec cap production deploy

15. Gotchas
 Shared directory structure on the server has
changed from version 2.
 Shared
[linked files / folders]
Assets
Bundle
 Migrations happen automatically
 Deployment flow terminology has changed

16. References
http://capistranorb.com/
https://github.com/capistrano
https://github.com/capistrano/capistrano
https://github.com/capistrano/rails

17. Questions?
Creston Jamison
@crestonjamison
creston.jamison@rubytreesoftware.com