Rake pre_deploy task for pre-compiling rails and ember assets, then updating the rails manifest file to point to ember-cli fingerprinted assets

pre_deploy.rake

require 'fileutils'

namespace :wildland do
  namespace :pre_deploy do
    namespace :precompile_assets do
      task :rails do
        system('RAILS_ENV=production bundle exec rake assets:precompile')
      end

      task :ember do
        Dir.chdir('ember') do
          sh 'DISABLE_FINGERPRINTING=false ./node_modules/.bin/ember build --environment=production'
        end
      end

      task :combine do
        FileUtils.rm_r('public/assets/admin_panel', force: true)
        FileUtils.cp_r('ember/dist/assets', 'public/assets/admin_panel')

        rails_manifest = Manifest.new(rails_assets_manifest_path)
        ember_manifest = Manifest.new(ember_assets_manifest_path)
        combine_manifests(rails_manifest, ember_manifest)

        FileUtils.rm(ember_assets_manifest_path)
        File.open(rails_assets_manifest_path, "w") do |f|
          f.write(rails_manifest.manifest.to_json)
        end
      end

      task all: [:rails, :ember, :combine]
    end

    task precompile_assets: ['precompile_assets:all']
  end

  task pre_deploy: ['pre_deploy:precompile_assets'] do
    Rake::Task['wildland:pre_deploy:precompile_assets'].invoke
  end
end

class Manifest
  attr_reader :manifest

  def initialize(path)
    @manifest = JSON.parse(File.read(path))
  end

  def assets
    manifest['assets']
  end

  def files
    manifest['files']
  end
end

def ember_assets_manifest_path
  Dir["public/assets/admin_panel/manifest.json"].first || Dir["public/assets/admin_panel/manifest*.json"].first
end

def rails_assets_manifest_path
  Dir["public/assets/.sprockets-manifest.json"].first || Dir["public/assets/.sprockets-manifest*.json"].first
end

def combine_manifests(rails_manifest, ember_manifest)
  ember_manifest.assets.each_pair do |key, value|
    prefix_path = "admin_panel\/"
    non_fingerprinted_filepath = "#{prefix_path}#{key}"
    fingerprinted_filepath = "#{prefix_path}#{value}"

    if rails_manifest.assets.has_key?(non_fingerprinted_filepath)
      files_fingerprinted_key = rails_manifest.assets[non_fingerprinted_filepath]
      rails_manifest.files.delete(files_fingerprinted_key)
    end

    rails_manifest.assets[non_fingerprinted_filepath] = fingerprinted_filepath
    rails_manifest.files[fingerprinted_filepath] = ember_manifest.files[value].clone
    rails_manifest.files[fingerprinted_filepath]['logical_path'] = non_fingerprinted_filepath
  end
end

I have the merged one (which looks just like the original rails one just with the fingerprints from the ember manifest merged in) and the ember one, does that work? If not, I can generate some new sets.

https://gist.github.com/Samsinite/b3ab6da492952bf94573