Capistrano::Rails

Rails specific tasks for Capistrano v3:

cap deploy:migrate
cap deploy:compile_assets

Installation

Add these lines to your application's Gemfile:

group :development do
  gem 'capistrano', '~> 3.6'
  gem 'capistrano-rails', '~> 1.3'
end

Run the following command to install the gems:

bundle install

Then run the generator to create a basic set of configuration files:

bundle exec cap install

Usage

Require everything (bundler, rails/assets and rails/migrations):

# Capfile
require 'capistrano/rails'

Or require just what you need manually:

# Capfile
require 'capistrano/bundler' # Rails needs Bundler, right?
require 'capistrano/rails/assets'
require 'capistrano/rails/migrations'

Please note that any requires should be placed in Capfile, not in config/deploy.rb.

You can tweak some Rails-specific options in config/deploy.rb:

# If the environment differs from the stage name
set :rails_env, 'staging'

# Defaults to :db role
set :migration_role, :db

# Defaults to the primary :db server
set :migration_servers, -> { primary(fetch(:migration_role)) }

# Defaults to false
# Skip migration if files in db/migrate were not modified
set :conditionally_migrate, true

# Defaults to [:web]
set :assets_roles, [:web, :app]

# Defaults to 'assets'
# This should match config.assets.prefix in your rails config/application.rb
set :assets_prefix, 'prepackaged-assets'

# RAILS_GROUPS env value for the assets:precompile task. Default to nil.
set :rails_assets_groups, :assets

# If you need to touch public/images, public/javascripts, and public/stylesheets on each deploy
set :normalize_asset_timestamps, %w{public/images public/javascripts public/stylesheets}

# Defaults to nil (no asset cleanup is performed)
# If you use Rails 4+ and you'd like to clean up old assets after each deploy,
# set this to the number of versions to keep
set :keep_assets, 2

Symlinks

You'll probably want to symlink Rails shared files and directories like log, tmp and public/uploads. Make sure you enable it by setting linked_dirs and linked_files options:

# deploy.rb
set :linked_dirs, fetch(:linked_dirs, []).push('log', 'tmp/pids', 'tmp/cache', 'tmp/sockets', 'vendor/bundle', 'public/system', 'public/uploads')
set :linked_files, fetch(:linked_files, []).push('config/database.yml', 'config/secrets.yml')

Recommendations

While migrations looks like a concern of the database layer, Rails migrations are strictly related to the framework. Therefore, it's recommended to set the role to :app instead of :db like:

set :migration_role, :app

The advantage is you won't need to deploy your application to your database server, and overall a better separation of concerns.

Contributing