InWork/queue_dispatcher

= QueueDispatcher for Rails3 / Rails4

{<img src="https://codeclimate.com/github/InWork/queue_dispatcher.png" />}[https://codeclimate.com/github/InWork/queue_dispatcher]

This Rails3 Gem implements a method to perform long running methods in the background.
Background tasks will be executed by persistent workers.

== Install

Inside your Gemfile:
  gem "queue_dispatcher"

and then run:
  bundle install

To install the queue_worker_dispatcher script, which starts all workers, execute the following rake command:
  rake queue_dispatcher:sync

=== Database Setup

Use
  rails g queue_dispatcher:migration

This will create a database migration for the models Task and TaskQueues.

If you update the queue_dispatcher from pre 1.5.1 you have to use the following command to update your migrations:

Use
  rails g queue_dispatcher:migration --skip

This will create all new database migrations for the models Task and TaskQueues and leve the existing as they are.

=== Gem Dependencies

Please check if all those requirements are satisfied on your environment.

* rails >= 3.0.0
* sys-proctable >= 0.9.1


== Inside your application

To enqueue a long running task, simple call a method through enque.
E.g.:
Assume, you have a long running job:
  LongRunningMailJob.send_mail

Now we'd like to execute it in the background by simply calling:
  task = LongRunningMailJob.enqueue.send_mail

If you like to put the job in a queue, you can do this by execute it the following way:
  task = LongRunningMailJob.enqueue(queue: 'queue_name').send_mail

Jobs inside a queue are executed serialized, not in parallel. You can define dependencies. A task is then executed only after all dependent tasks are finished. The dependencies could also be in another queue. This way you could ensure, that a task is only executed when another task from another queue is successfully finished. Code to add Task dependencies:
  task.dependent_tasks = another_task

=== Queue Worker Dispatcher
The QueueWorkerDispatcher-script starts the workers (default are 10 workers). A worker waits for a new queue and executes all tasks of this queue. Start the QueueWorkerDispatcher by executing the following command:
  script/queue_worker_dispatcher

To start the QueueWorkerDispatcher as a daemon, use the option -b.
  -b, --background        work in background mode

== License
This project is licenced under the MIT license.

== Author
Philip Kurmann (philip (at) kman.ch)