Deep record dump

Deep record dump

# Deep record dump
#
# Usage:
#   dump = DeepRecordDump.new(order)
#
# 1) build sql dump file
#   dump.write('/var/www/your_app/tmp/order_nnn.sql')
# 2) build shell commands to restore assets
#   puts dump.shell_dump
# 3) restore `mysql db_name -e 'source /var/www/your_app/tmp/order_nnn.sql'` !!! NOT  mysql db_name < dump.sql !!!
# 4) run shell commands
#
class DeepRecordDump

  attr_accessor :dump_records

  def initialize(record, dump_records={}, options={})
    @options = options
    @options.reverse_merge!(dependent: false)
    @record = record
    @dump_records = dump_records
  end

  def dump
    @dump ||= build_dump_records.values
  end

  def build_dump_records
    dump_records[key_for(@record)] ||= dump_for(@record)

    dump_associations.each do |assoc|
      Array(@record.send(assoc.name)).each do |record|
        dump_records[key_for(record)] or DeepRecordDump.new(record, dump_records, @options).build_dump_records
      end
    end

    dump_records
  end

  def dump_associations
    @record.class.reflect_on_all_associations.reject { |assoc| !@options[:dependent] && !assoc.options[:dependent] }
  end

  def dump_for(record)
    data = {sql: insert_for(record)}
    data[:shell] = shell_for(record) if record.class.table_name == 'assets'
    data
  end

  def insert_for(record)
    arel = record.class.arel_table.create_insert
    arel.insert(record.send(:arel_attributes_with_values_for_create, record.attribute_names))
    arel.to_sql
  end

  def shell_for(record)
    store_relative_dir = record.data.store_dir
    target_dir = "/var/www/your_app/public/#{store_relative_dir}"
    backup_dir = "/var/backups/content/#{store_relative_dir}/"
    "mkdir -p #{target_dir} && rsync -a backup:#{backup_dir} #{target_dir}"
  end

  def key_for(record)
    "#{record.class.table_name}##{record.id}"
  end

  def sql_dump
    dump.map { |d| d[:sql] }.join(";\n")
  end

  def shell_dump
    dump.map { |d| d[:shell] }.compact.join("\n")
  end

  def write(path)
    File.write(path, sql_dump)
  end
end