Local Asset Precompilation with Capistrano and AssetSync

assets.rb

# 
# = Capistrano Assets recipe
#
# Provides a couple of tasks for precompiling assets locally
# Assumes usage of AssetSync to deploy to CloudProvider or CDN 
# 
# Inspired by http://www.rostamizadeh.net/blog/2012/04/14/precompiling-assets-locally-for-capistrano-deployment

namespace :deploy do

  namespace :assets do

    desc <<-DESC
      Precompiles assets locally.  If you are using AssetSync, it should send them
      to the cloud automatically.
    DESC
    task :precompile, roles: :web do
      # i keep this in so that it triggers login at the beginning of the process
      from = source.next_revision(current_revision)
      run_locally("rake assets:clean && rake assets:precompile")
      run_locally "cd public && tar -jcf assets.tar.bz2 assets"
      top.upload "public/assets.tar.bz2", "#{shared_path}", :via => :scp
      run "cd #{shared_path} && tar -jxf assets.tar.bz2 && rm assets.tar.bz2"
      run_locally "rm public/assets.tar.bz2"
      run_locally("rake assets:clean")
    end

    desc <<-DESC
      Sync assets to the cloud via Asset Sync.  Must be run remotely(so it pulls remote aws credentials)
      and after code is deployed so it gets proper asset manifest to sync
    DESC
    task :sync, roles: :web do
      run("cd #{latest_release} && /usr/bin/env rake assets:sync RAILS_ENV=production")
    end
    
    desc <<-DESC
      [internal] Updates the symlink for assets
    DESC
    task :symlink, roles: :web do
      run ("rm -rf #{latest_release}/public/assets &&
            mkdir -p #{latest_release}/public &&
            mkdir -p #{shared_path}/assets &&
            ln -s #{shared_path}/assets #{latest_release}/public/assets")
    end

  end

end