Capistrano tasks to deploy from commit references and separate repos

tag_deploy.rb

# Have `cap deploy` ask for tag to deploy from. Can be automated like this `cap deploy TAG=some-tag-name`

set :branch do
  if ENV['REF']     # Tag passed in via arg
    ref = ENV['REF']
  else              # Prompt for reference to use
    default_ref = `git tag`.split("\n").last

    ref = Capistrano::CLI.ui.ask "Tag to deploy (make sure repo is up to date): [#{default_ref}] "
    ref = default_ref if ref.empty?
  end
  logger.log Logger::INFO, "Deploying with commit reference: #{ref}"
  ref
end

set :repository do
  repo = if ENV['REPO'] 
    ENV['REPO']
  elsif ENV['REMOTE']
    `git remote show -n #{ENV['REMOTE']} | grep "Push  URL"`.split.last
  else
    "git@github.com:Default/repo.git"
  end
  logger.log Logger::INFO, "Deploying from repo: #{repo}"
  repo
end