mongoid backend support. courtesy of dohmoose.

README.textile

@@ -62,6 +62,32 @@ MongoMapper.setup(config, Rails.env)
 Delayed::Worker.backend = :mongo_mapper
 </pre>
 
+h3. Mongoid
+
+You need to create your DelayedJob mongoid model:
+<pre>
+# app/models/delayed_job.rb
+class DelayedJob
+  include Mongoid::Document
+  include Mongoid::Timestamps
+
+  field :priority, :type => Integer, :default => 0      # Allows some jobs to jump to the front of the queue
+  field :attempts, :type => Integer, :default => 0      # Provides for retries, but still fail eventually.
+  field :handler                      # YAML-encoded string of the object that will do work
+  field :last_error                   # reason for last failure (See Note below)
+  field :run_at, :type => DateTime                       # When to run. Could be Time.zone.now for immediately, or sometime in the future.
+  field :locked_at, :type => DateTime                    # Set when a client is working on this object
+  field :failed_at, :type => DateTime                    # Set when all retries have failed (actually, by default, the record is deleted instead)
+  field :locked_by                    # Who is working on this object (if locked)
+end
+</pre>
+
+And set the backend in the initializer:
+<pre>
+# config/initializers/delayed_job.rb
+Delayed::Worker.backend = :mongoid
+</pre>
+
 h3. DataMapper
 
 <pre>

lib/delayed/backend/mongoid.rb

@@ -0,0 +1,98 @@
+Mongoid::Document.class_eval do
+  yaml_as "tag:ruby.yaml.org,2002:Mongoid"
+
+  def self.yaml_new(klass, tag, val)
+    begin
+      klass.find(val['attributes']['_id'])
+    rescue Mongoid::Errors::DocumentNotFound
+      nil
+    end
+  end
+
+  def to_yaml_properties
+    ['@attributes']
+  end
+end
+
+module Delayed
+  module Backend
+    module Mongoid
+      class Job
+        include ::Mongoid::Document
+        include ::Mongoid::Timestamps
+        include Delayed::Backend::Base
+        field :priority,    :type=> Integer, :default => 0
+        field :attempts,    :type=> Integer, :default => 0
+        field :handler,     :type=> String
+        field :run_at,      :type=> Time
+        field :locked_at,   :type=> Time
+        field :locked_by,   :type=> String, :index => true
+        field :failed_at,   :type=> Time
+        field :last_error,  :type=> String
+
+
+        before_save :set_default_run_at
+
+        def self.before_fork
+          ::Mongoid.master.connection.close
+        end
+
+        def self.after_fork
+          ::Mongoid.master.connection.connect_to_master
+        end
+
+        def self.db_time_now
+          Time.now.utc
+        end
+
+        def self.find_available(worker_name, limit = 5, max_run_time = Worker.max_run_time)
+          right_now = db_time_now
+
+          conditions = {:run_at  => {"$lte" => right_now}, :failed_at => nil}
+          (conditions[:priority] ||= {})['$gte'] = Worker.min_priority.to_i if Worker.min_priority
+          (conditions[:priority] ||= {})['$lte'] = Worker.max_priority.to_i if Worker.max_priority
+
+
+          where = "this.locked_at == null || this.locked_at < #{make_date(right_now - max_run_time)}"
+          results = self.where(conditions.merge(:locked_by => worker_name)).limit(-limit).order_by([['priority', 1], ['run_at', 1]]).to_a
+          results += self.where(conditions.merge('$where' => where)).limit(-limit+results.size).order_by([['priority', 1], ['run_at', 1]]).to_a if results.size < limit
+          results
+        end
+        # When a worker is exiting, make sure we don't have any locked jobs.
+        def self.clear_locks!(worker_name)
+          self.collection.update({:locked_by => worker_name}, {"$set" => {:locked_at => nil, :locked_by => nil}}, :multi => true)
+        end
+
+        # Lock this job for this worker.
+        # Returns true if we have the lock, false otherwise.
+        def lock_exclusively!(max_run_time, worker = worker_name)
+          right_now = self.class.db_time_now
+          overtime = right_now - max_run_time.to_i
+
+          query = "this.locked_at == null || this.locked_at < #{make_date(overtime)} || this.locked_by == #{worker.to_json}"
+          conditions = {:_id => id, :run_at => {"$lte" => right_now}, "$where" => query}
+
+          self.collection.update(conditions, {"$set" => {:locked_at => right_now, :locked_by => worker}})
+          affected_rows = self.collection.find({:_id => id, :locked_by => worker}).count
+          if affected_rows == 1
+            self.locked_at = right_now
+            self.locked_by = worker
+            return true
+          else
+            return false
+          end
+        end
+
+        private
+
+        def self.make_date(date_or_seconds)
+        "new Date(#{date_or_seconds.to_f * 1000})"
+        end
+
+        def make_date(date)
+          self.class.make_date(date)
+        end
+      end
+    end
+  end
+end

lib/delayed/worker.rb

@@ -43,6 +43,8 @@ def self.guess_backend
         :active_record
       elsif defined?(MongoMapper)
         :mongo_mapper
+      elsif defined?(Mongoid)
+        :mongoid
       else
         logger.warn "Could not decide on a backend, defaulting to active_record"
         :active_record

spec/backend/mongoid_job_spec.rb

@@ -0,0 +1,41 @@
+require 'spec_helper'
+require 'backend/shared_backend_spec'
+require 'delayed/backend/mongoid'
+
+describe Delayed::Backend::Mongoid::Job do
+  before(:all) do
+    @backend = Delayed::Backend::Mongoid::Job
+    Delayed::Worker.backend = :mongoid
+  end
+
+  before(:each) do
+    Delayed::Backend::Mongoid::Job.destroy_all
+  end
+
+  it_should_behave_like 'a backend'
+
+
+  describe "before_fork" do
+    after do
+      ::Mongoid.master.connection.close
+    end
+
+    it "should disconnect" do
+      lambda do
+        Delayed::Backend::Mongoid::Job.before_fork
+      end.should change { !!Mongoid.master.connection.connected? }.from(true).to(false)
+    end
+  end
+
+  describe "after_fork" do
+    before do
+      ::Mongoid.master.connection.close
+    end
+
+    it "should call reconnect" do
+      lambda do
+        Delayed::Backend::Mongoid::Job.after_fork
+      end.should change { !!Mongoid.master.connection.connected? }.from(false).to(true)
+    end
+  end
+end

spec/setup/mongoid.rb

@@ -0,0 +1,17 @@
+require 'mongoid'
+
+require 'delayed/backend/mongoid'
+
+Mongoid.configure do |config|
+  config.master = config.master = Mongo::Connection.new.db('dl_spec') 
+end
+
+class Story
+  include ::Mongoid::Document
+  def tell; text; end       
+  def whatever(n, _); tell*n; end
+  def self.count; end
+
+  handle_asynchronously :whatever
+end
+

spec/spec_helper.rb

@@ -20,8 +20,8 @@
     require "setup/#{backend}"
     require "backend/#{backend}_job_spec"
     BACKENDS << backend.to_sym
-  rescue Exception
-    puts "Unable to load #{backend} backend: #{$!}"
+  rescue LoadError
+   	puts "Unable to load #{backend} backend: #{$!}"
   end
 end