Best way to ensure ordering of a queue.

[wwahammy]

Maybe this isn't the exect best place for bringing this up but I'm trying to understand how good_job can help me.

I have a set of jobs that operate on a same objects. I need to record the changes on another system in the exact same order they were sent in. In effect, I need to make sure that if processing a job fails in a queue, that all of the jobs behind that job in the queue would be stuck until the first one was corrected somehow.

Is there a good way to do that using good_job?

[bensheldon]

@wwahammy this is an interesting challenge. I'm curious about how the sequence of operations is determined.

If I think of systems I have worked on, I would track the state of this outside of GoodJob. For example, if it was maintenance of a car:

class Car
  has_many :maintenance_tasks
  has_many :uncompleted_maintenance_tasks, -> { uncompleted.order(created_at: :asc) }, class_name: "MaintenanceTask"
end

class MaintenanceTask
  belongs_to :car
  scope :uncompleted, -> { where(completed_at: nil) }
end

class CarMaintenanceJob < ApplicationJob
  def perform(car)
    task = car.uncompleted_maintenance_tasks.first
    # do the task, or raise an exception that would prevent the following from running...
    task.touch(:completed_at)
    CarMaintenanceJob.perform_later(car) if car.uncompleted_maintenance_tasks.any?
  end
end

# And the sequence of operations would be determined by calling 
# `car.create_maintenance_task(task_params)` for each task 
# that needs to be performed.