Speed up assets:precompile with Rails 3.1/3.2 Capistrano deployment

Question

My deployments are slow, they take at least 3 minutes. The slow Capistrano task during deploy is assets:precompile. This takes probably 99% of the total deploy time. How can

Answer 1

The solution that Ben Curtis propose does not work for me, because I do not copy the .git folder when deploying (slow and useless) :

set :scm, :git
set :deploy_via, :remote_cache
set :copy_exclude, ['.git']

I'm using the following snippet, whitout load 'deploy/assets'

task :assets, :roles => :app do
  run <<-EOF
    cd #{release_path} &&
    rm -rf public/assets &&
    mkdir -p #{shared_path}/assets &&
    ln -s #{shared_path}/assets public/assets &&
    export FROM=`[ -f #{current_path}/REVISION ] && (cat #{current_path}/REVISION | perl -pe 's/$/../')` &&
    export TO=`cat #{release_path}/REVISION` &&
    echo ${FROM}${TO} &&
    cd #{shared_path}/cached-copy &&
    git log ${FROM}${TO} -- app/assets vendor/assets | wc -l | egrep '^0$' ||
    (
      echo "Recompiling assets" &&
      cd #{release_path} &&
      source .rvmrc &&
      RAILS_ENV=production bundle exec rake assets:precompile --trace
    )
  EOF
end