retriable

gistfile1.rb

module Retriable
  class RepeatedError < RuntimeError
    def initialize(max, *args)
      @errors = []
      @max    = max
      super(*args)
    end

    def <<(e)
      @errors << e
    end

    def still_retriable?
      @max > error_count
    end

    def error_count
      @errors.size
    end
  end

  def with_retry(max_retry = 3)
    repeatable_error = Retriable::RepeatedError.new(max_retry)

    begin
      return yield
    rescue => ex
      repeatable_error << ex

      if repeatable_error.still_retriable?
        sleep 3 * 2 ** (repeatable_error.error_count - 1)
        retry
      else
        raise repeatable_error
      end
    end
  end
end

class Foo
  include Retriable

  def hi(max)
    n = 0
    with_retry do
      p :hi
      n += 1

      raise if n < max
    end
  end
end

Foo.new.hi(3)
Foo.new.hi(4)