backup_servvice.rb

# You'll need activerecord-import gem installed in your app

class BackupService
  def initialize(path: nil)
    @path = path || Rails.root.join('tmp', "backup-#{Time.now.to_i}.sqlite")
  end

  def backup(*scopes)
    with_db do
      prepare
      scopes.each do |scope|
        backup_scope(scope)
      end
    end
    true
  end

  private

  def prepare
    raise "expecting to use a sqlite3 database connection" unless ActiveRecord::Base.connection.adapter_name == 'SQLite'
    Rails.logger.silence do
      ActiveRecord::Schema.verbose = false
      load(ActiveRecord::Tasks::DatabaseTasks.schema_file)
    end
  end

  def backup_scope(scope)
    columns = scope.model.column_names
    values = scope.pluck(*columns)
    Rails.logger.silence do
      scope.model.import(columns, values, validate: false)
    end
  end

  def with_db
    begin
      ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: @path)
      yield
    ensure
      ActiveRecord::Base.connection.disconnect!
      ActiveRecord::Base.remove_connection
      ActiveRecord::Base.establish_connection
    end
  end
end

# Usage:
# service = BackupService.new
# service.backup User.all, Company.all