Capistrano is a tool for deploying and releasing Ruby applications. It allows automating common deployment tasks like code updates, database migrations, and server restarts. Capistrano uses SSH for connectivity and works with many version control systems. Configuration is done in a Capfile and deploy.rb files where you specify application details, repositories, roles, and tasks like database setup. Capistrano then automates deploying code, running migrations, and restarting services.

1. Deploying Rails applications with
Capistrano
http://www.flickr.com/photos/jsome1/2226394415

2. What is Capistrano?
http://www.flickr.com/photos/dionisio/2481071707

3. requirements
Ruby + Rake SCM SSH

4. installation
$ gem install capistrano

5. assumptions
●
We are using SSH. Telnet and FTP are not
supported
●
Servers have POSIX-compatible shell
●
SSH Keys configured

6. capification
$ cd my_app
$ cap .
/my_app
| - Capifile
| - /config/deploy.rb

7. 1/2
configuration
set :application, “siege”
set :repository, “git@github.com:m3nd3s/siege.git”
set :scm, :git
set :branch, “master”
set :ssh_options, { :forward_agent => true }
set :user, “giran”
set :deploy_to, “/home/giran/siege”
set :my_var, “Giran Siege”
config/deploy.rb

8. 2/2
configuration
role :web, “siege.giran.com.br”
role :app, “siege.giran.com.br”
role :db, “siege.giran.com.br”

9. tasks
task :acceptance do
set :user, "root"
set :deploy_to, "/var/www/siege"
end

10. setting up
$ cap deploy:setup
# Or cascaded tasks
$ cap acceptance deploy:setup

11. structure
[deploy_to]
[deploy_to]/releases
[deploy_to]/shared
[deploy_to]/shared/log
[deploy_to]/shared/pids
[deploy_to]/shared/system

12. database
●
Database needs to be created
namespace :deploy do
task :database, :roles => :app do
run "cp #{deploy_to}/shared/database.yml
#{current_path}/config/"
end
end

13. deploy
$ cap deploy
# Or cascaded tasks
$ cap acceptance deploy

14. after and before
after :deploy, 'deploy:database'
namespace :deploy do
...
end

15. restart
namespace :deploy do
task :restart, :roles => :app, :except => {
:no_release => true } do
run "cd #{current_path} && touch
tmp/restart.txt"
end
end

16. http://www.flickr.com/photos/mpawl/1572150843

17. references
https://github.com/capistrano/capistrano/wiki/_pages

18. thank you !
Almir 'm3nd3s'
@m3nd3s
http://www.almirmendes.com
almir.mendes@giran.com.br
m3nd3s@gmail.com
http://www.flickr.com/photos/meepfriends/2279161806