# encoding: utf-8

## pulled from mongoid

# Provides behaviour for retrying commands on connection failure.
module Mongo::Retry

  # Retries command on connection failures.
  #
  # This is useful when using replica sets. When a primary server wents
  # down and a command is issued, the driver will raise a
  # Mongo::ConnectionFailure. We wait a little bit, because nodes are
  # electing themselves, and then retry the given command.
  #
  # By setting Mongoid.max_retries_on_connection_failure to a value of 0,
  # no attempt will be made, immediately raising connection failure.
  # Otherwise it will attempt to make the specified number of retries
  # and then raising the exception to clients.
  #
  # @example Retry the command.
  #   retry_on_connection_failure do
  #     collection.send(name, *args)
  #   end
  #
  # @since 2.0.0
  def retry_on_connection_failure
    retries = 0
    begin
      yield
    rescue Mongo::ConnectionFailure => ex
      retries += 1
      raise ex if retries > 30  # Config.max_retries_on_connection_failure
      Kernel.sleep(0.5) ## Todo.. modify for event machine
      log_retry retries
      retry
    end
  end

  private

  def log_retry(retry_number)
    puts "A Mongo::ConnectionFailure was raised. Retry attempt ##{retry_number}."
  end
end