deploy rails app to remote server, which has a limited internet access.

deploy.rb

# config/deploy.rb

namespace :deploy do
  desc "check local vendor/cache"
  task :bundled_package do
    run_locally do
      unless test "[[ -d #{File.expand_path("../../vendor/cache", __FILE__)} ]]"
        error "please `bundle package --all` first!"
        raise StandardError
      end
    end
  end
  
  desc "upload vendor/cache for local gem install"
  task :upload_vendor_cache do
    on roles(:app) do
      upload! File.expand_path("../../vendor/cache", __FILE__),
        "#{shared_path}/vendor",
        recursive: true
    end
  end
end

production.rb

# config/deploy/production.rb

# link vendor/cache
set :linked_dirs, fetch(:linked_dirs, []).push("vendor/cache")

# check local vendor/cache first
before "deploy:starting", "deploy:bundled_package"

# upload cache to remote
before "bundler:install", "deploy:upload_vendor_cache"