Mongo-Resque is a fork of Resque based on MongoDB instead of Redis.
All work on this project is sponsored by the online video platform Streamio.
Check out the ORIGINAL_README included in this repository for the general Resque lowdown.
Apart from transparently replacing the redis backend with mongodb (where each queue has a corresponding mongo collection) this fork also features delayed jobs if you want to schedule your jobs.
Note that this fork is different from IGO's fork in that queue collections are namespaced with 'resque.queues.' to make it possible to use the same database for your application as Resque (this might still not be the best idea though - behold the stern warnings below).
Original resque is currently using hoptoad_notifier in its Hoptoad Failure Backend and the airbrake gem for its Airbrake Faiure Backend. This fork has chosen not to add these dependencies but rather have its own clean support for Airbrake (the Hoptoad backend has been deprecated).
If your job class indicates that @delayed = true, you can queue delayed jobs. These jobs will not be popped off the queue until the Time indicated in arg[:delay_until] has come. Note that you must call Resque.enable_delay(:queue) before enququing any delayed jobs, to ensure that the performance impact on other queues is minimal.
Make sure you use the right require in your Gemfile.
gem 'mongo-resque', :require => 'resque'
Resque.redis= has been replaced with Resque.mongo= and expects a Mongo::DB object as an argument.
Resque.mongo = Mongo::Connection.new.db("my_awesome_queue")
Sometimes, Mongo-Resque will drop a queue collection, or create some indexes, or otherwise manipulate its database. For this reason, it is STRONGLY recommended that you give it its own database in mongo.
All jobs should be queued via Resque.enqueue. All arguments passed to this method must be BSON-encodable. Mongo-Resque does not serialize your objects for you. Arrays, Hashes, Strings, Numbers, and Times are all ok, so don't worry.
Many of the new queue-level features require the first argument of your perform method to be an options hash. In fact, if you just start making all your perform()s take one param, that is an options hash, you'll probably save yourself some pain.
Mongo-Resque will not create any indexes on your queues, only on its meta-data. You will need to create any indexes you want. Normally, This is not a problem, because you aren't querying by keys, but you may want to create indexes on the class key in some circumstances. If you use the unique or delay features, you may want some additional indexes, depending on the nature of your workload. Paranoid? Test enqueuing and processing all your jobs, and run with --notablescans. Learn the profiler, and use it often.
Specifically, a queue with many long-delayed jobs will result in slower queue pops for all jobs using that queue. Index delay_until in the case of thousands of delayed jobs.