Take2

1. Define rules for retrying behavior.
2. Yield block of code into the with_retry method.
3. Things getting take two :)

Install

gem install take2

Examples

class Service
  include Take2

  number_of_retries 3

  # Could be configured globally or on class level.
  retriable_errors Net::HTTPRetriableError, Errno::ECONNRESET

  # Retry unless the response status is 5xx. The implementation is dependent of the http lib in use.
  retriable_condition proc { |error| error.response.code < 500 }

  # Defines callable code to run before next retry. Could be an out put to some logger.
  on_retry proc { |error, tries| puts "#{name} - Retrying.. #{tries} of #{retriable_configuration[:retries]} (#{error})" }

  # The available strategies are:
  # type :constant, start: 2 => [2, 2, 2, 2 ... ]
  # type :linear, start: 3, factor: 2 => [3, 6, 12, 24 ... ]
  # type :fibonacci, start: 2 => [2, 3, 5, 8, 13 ... ]
  # type :exponential, start: 3 => [3, 7, 12, 28, 47 ... ]
  backoff_strategy type: :fibonacci, start: 3

  class << self
    def call
      with_retry do
        # Some logic that might raise..
        # If it will raise retriable, magic happens.
        # If not the original error re raised

        raise Net::HTTPRetriableError.new('Release the Kraken...many times!!', nil)
      end
    end

    # Pass custom options per method call
    # The class defaults will not be overwritten
    def read(file)
      with_retry(retries: 2, retriable: [IOError], retry_proc: proc {}, retry_condition_proc: proc {}) do
        # Some logic that might raise..
      end
    end
  end
end  

Service.call
#=> KratosService - Retrying.. 3 of 3 (Release the Kraken...many times!!)
#=> KratosService - Retrying.. 2 of 3 (Release the Kraken...many times!!)
#=> KratosService - Retrying.. 1 of 3 (Release the Kraken...many times!!)
# After the retrying is done, original error re-raised  
#=> Net::HTTPRetriableError: Release the Kraken...many times!!

# Current configuration hash
Service.retriable_configuration

Configurations

could be implemented as rails initializer

# config/initializers/take2.rb

Take2.configure do |config|
  config.retries    = 3
  config.retriable  = [
      Net::HTTPRetriableError,      
      Errno::ECONNRESET,
      IOError
  ].freeze
  config.retry_condition_proc = proc { false }
  config.retry_proc           = proc { Rails.logger.info "Retry message" }
  config.backoff_intervals    = Take2::Backoff.new(:linear, 1).intervals
end