sidekiq-after_transaction.rb

# Weak ACID semantics for Sidekiq jobs
#
# Include this module in a Sidekiq::Worker class and it will defer enqueuing
# jobs for that worker within an open ActiveRecord transaction until it is
# committed. Rollbacks will prevent any jobs being enqueued at all.
#
# ActiveRecord keeps track of all records which are being utilized within a
# transaction so it can fulfil commit and rollback callbacks. We create a fake
# record that quacks the same way for the same hooks.
#
# Inspired by: http://blog.arkency.com/2015/10/run-it-in-background-job-after-commit/
#
module Sidekiq::AfterTransaction
  extend ActiveSupport::Concern

  class Error < RuntimeError; end
  class PushError < Error; end

  module ClassMethods
    def client_push(*args)
      if ActiveRecord::Base.connection.transaction_open?
        ActiveRecord::Base.connection.current_transaction.add_record(Record.new(self, *args))
      else
        super(*args)
      end
    end
  end

  class Record
    def initialize(klass, *args)
      @klass = klass
      @args = args
    end

    delegate :logger, to: :Sidekiq

    def has_transaction_callbacks?
      true
    end

    def before_committed!(*)
    end

    def committed!(*)
      logger.debug("[Sidekiq::AfterTransaction]: Commit, pushing Sidekiq job: #{@klass.name}.client_push(#{@args.inspect[1...-1]})")
      @klass.client_push(*@args)
    rescue
      raise PushError.new("Transaction committed but Sidekiq push failed")
    end

    def rolledback!(*)
      logger.debug "[Sidekiq::AfterTransaction]: Rollback, discarding Sidekiq job: #{@klass.name}.client_push(#{@args.inspect[1...-1]})"
    end
  end
end