ActiveStorage - Dump files from AWS S3 storage

activestorage_dump_files_from_s3.rb

namespace :storage do
  desc 'Downloading All Files from AWS - S3'
  
  task dump: :environment do
    verify_environment!
    ActiveStorage::Blob.establish_connection(:development)
    ActiveStorage::Blob.find_each do |blob|
      path = make_path_for(blob.key)
      if FileTest.exists?(path)
        puts "ALREADY EXISTS #{blob.key} : => #{blob.filename}"
      else
        puts "DOWNLOADING #{blob.key} : => #{blob.filename}"
        File.open(path, 'wb') do |file|
          file.write(blob.download)
        rescue Aws::S3::Errors::NoSuchKey
          puts "DOES NOT EXIST: => #{blob.key}"
        end
      end
    end
  end

  # Restrict to run this task only on Production env because that's where we have S3 storage usually.
  def verify_environment!
    abort('FAILED!! -> Please run this task with RAILS_ENV=production') unless Rails.env.production?
  end

  def make_path_for(key)
    path_for(key).tap { |path| FileUtils.mkdir_p(path) }.join(key)
  end

  def path_for(key)
    Rails.root.join('storage').join(folder_for(key))
  end

  def folder_for(key)
    [key[0..1], key[2..3]].join('/')
  end
end