Add job priorities to ActiveJob

11 files changed, 132 insertions, 6 deletions

diff --git a/activejob/CHANGELOG.md b/activejob/CHANGELOG.md
index 965b556fab..b5742191eb 100644
--- a/activejob/CHANGELOG.md
+++ b/activejob/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Add job priorities to Active Job.
+
+    *wvengen*
+
 *   Implement a simple `AsyncJob` processor and associated `AsyncAdapter` that
     queue jobs to a `concurrent-ruby` thread pool.
 
diff --git a/activejob/lib/active_job/base.rb b/activejob/lib/active_job/base.rb
index 5d7c4cfb91..e5f09f65fb 100644
--- a/activejob/lib/active_job/base.rb
+++ b/activejob/lib/active_job/base.rb
@@ -1,6 +1,7 @@
 require 'active_job/core'
 require 'active_job/queue_adapter'
 require 'active_job/queue_name'
+require 'active_job/queue_priority'
 require 'active_job/enqueuing'
 require 'active_job/execution'
 require 'active_job/callbacks'
@@ -57,6 +58,7 @@ module ActiveJob #:nodoc:
     include Core
     include QueueAdapter
     include QueueName
+    include QueuePriority
     include Enqueuing
     include Execution
     include Callbacks
diff --git a/activejob/lib/active_job/core.rb b/activejob/lib/active_job/core.rb
index eac7279309..19b900a285 100644
--- a/activejob/lib/active_job/core.rb
+++ b/activejob/lib/active_job/core.rb
@@ -18,6 +18,9 @@ module ActiveJob
       # Queue in which the job will reside.
       attr_writer :queue_name
 
+      # Priority that the job will have (lower is more priority).
+      attr_writer :priority
+
       # ID optionally provided by adapter
       attr_accessor :provider_job_id
 
@@ -43,6 +46,7 @@ module ActiveJob
       # * <tt>:wait</tt> - Enqueues the job with the specified delay
       # * <tt>:wait_until</tt> - Enqueues the job at the time specified
       # * <tt>:queue</tt> - Enqueues the job on the specified queue
+      # * <tt>:priority</tt> - Enqueues the job with the specified priority
       #
       # ==== Examples
       #
@@ -51,6 +55,7 @@ module ActiveJob
       #    VideoJob.set(wait_until: Time.now.tomorrow).perform_later(Video.last)
       #    VideoJob.set(queue: :some_queue, wait: 5.minutes).perform_later(Video.last)
       #    VideoJob.set(queue: :some_queue, wait_until: Time.now.tomorrow).perform_later(Video.last)
+      #    VideoJob.set(queue: :some_queue, wait: 5.minutes, priority: 10).perform_later(Video.last)
       def set(options={})
         ConfiguredJob.new(self, options)
       end
@@ -62,6 +67,7 @@ module ActiveJob
       @arguments  = arguments
       @job_id     = SecureRandom.uuid
       @queue_name = self.class.queue_name
+      @priority   = self.class.priority
     end
 
     # Returns a hash with the job data that can safely be passed to the
@@ -71,6 +77,7 @@ module ActiveJob
         'job_class'  => self.class.name,
         'job_id'     => job_id,
         'queue_name' => queue_name,
+        'priority'   => priority,
         'arguments'  => serialize_arguments(arguments),
         'locale'     => I18n.locale
       }
@@ -99,6 +106,7 @@ module ActiveJob
     def deserialize(job_data)
       self.job_id               = job_data['job_id']
       self.queue_name           = job_data['queue_name']
+      self.priority             = job_data['priority']
       self.serialized_arguments = job_data['arguments']
       self.locale               = job_data['locale'] || I18n.locale
     end
diff --git a/activejob/lib/active_job/enqueuing.rb b/activejob/lib/active_job/enqueuing.rb
index 98d92385dd..22154457fd 100644
--- a/activejob/lib/active_job/enqueuing.rb
+++ b/activejob/lib/active_job/enqueuing.rb
@@ -32,6 +32,7 @@ module ActiveJob
     # * <tt>:wait</tt> - Enqueues the job with the specified delay
     # * <tt>:wait_until</tt> - Enqueues the job at the time specified
     # * <tt>:queue</tt> - Enqueues the job on the specified queue
+    # * <tt>:priority</tt> - Enqueues the job with the specified priority
     #
     # ==== Examples
     #
@@ -54,6 +55,7 @@ module ActiveJob
     # * <tt>:wait</tt> - Enqueues the job with the specified delay
     # * <tt>:wait_until</tt> - Enqueues the job at the time specified
     # * <tt>:queue</tt> - Enqueues the job on the specified queue
+    # * <tt>:priority</tt> - Enqueues the job with the specified priority
     #
     # ==== Examples
     #
@@ -61,10 +63,12 @@ module ActiveJob
     #    my_job_instance.enqueue wait: 5.minutes
     #    my_job_instance.enqueue queue: :important
     #    my_job_instance.enqueue wait_until: Date.tomorrow.midnight
+    #    my_job_instance.enqueue priority: 10
     def enqueue(options={})
       self.scheduled_at = options[:wait].seconds.from_now.to_f if options[:wait]
       self.scheduled_at = options[:wait_until].to_f if options[:wait_until]
       self.queue_name   = self.class.queue_name_from_part(options[:queue]) if options[:queue]
+      self.priority     = options[:priority].to_i if options[:priority]
       run_callbacks :enqueue do
         if self.scheduled_at
           self.class.queue_adapter.enqueue_at self, self.scheduled_at
diff --git a/activejob/lib/active_job/queue_adapters/delayed_job_adapter.rb b/activejob/lib/active_job/queue_adapters/delayed_job_adapter.rb
index ac83da2b9c..0a785fad3b 100644
--- a/activejob/lib/active_job/queue_adapters/delayed_job_adapter.rb
+++ b/activejob/lib/active_job/queue_adapters/delayed_job_adapter.rb
@@ -14,13 +14,13 @@ module ActiveJob
     #   Rails.application.config.active_job.queue_adapter = :delayed_job
     class DelayedJobAdapter
       def enqueue(job) #:nodoc:
-        delayed_job = Delayed::Job.enqueue(JobWrapper.new(job.serialize), queue: job.queue_name)
+        delayed_job = Delayed::Job.enqueue(JobWrapper.new(job.serialize), queue: job.queue_name, priority: job.priority)
         job.provider_job_id = delayed_job.id
         delayed_job
       end
 
       def enqueue_at(job, timestamp) #:nodoc:
-        delayed_job = Delayed::Job.enqueue(JobWrapper.new(job.serialize), queue: job.queue_name, run_at: Time.at(timestamp))
+        delayed_job = Delayed::Job.enqueue(JobWrapper.new(job.serialize), queue: job.queue_name, priority: job.priority, run_at: Time.at(timestamp))
         job.provider_job_id = delayed_job.id
         delayed_job
       end
diff --git a/activejob/lib/active_job/queue_adapters/que_adapter.rb b/activejob/lib/active_job/queue_adapters/que_adapter.rb
index 90947aa98d..ab13689747 100644
--- a/activejob/lib/active_job/queue_adapters/que_adapter.rb
+++ b/activejob/lib/active_job/queue_adapters/que_adapter.rb
@@ -16,13 +16,13 @@ module ActiveJob
     #   Rails.application.config.active_job.queue_adapter = :que
     class QueAdapter
       def enqueue(job) #:nodoc:
-        que_job = JobWrapper.enqueue job.serialize
+        que_job = JobWrapper.enqueue job.serialize, priority: job.priority
         job.provider_job_id = que_job.attrs["job_id"]
         que_job
       end
 
       def enqueue_at(job, timestamp) #:nodoc:
-        que_job = JobWrapper.enqueue job.serialize, run_at: Time.at(timestamp)
+        que_job = JobWrapper.enqueue job.serialize, priority: job.priority, run_at: Time.at(timestamp)
         job.provider_job_id = que_job.attrs["job_id"]
         que_job
       end
diff --git a/activejob/lib/active_job/queue_priority.rb b/activejob/lib/active_job/queue_priority.rb
new file mode 100644
index 0000000000..01d84910ff
--- /dev/null
+++ b/activejob/lib/active_job/queue_priority.rb
@@ -0,0 +1,44 @@
+module ActiveJob
+  module QueuePriority
+    extend ActiveSupport::Concern
+
+    # Includes the ability to override the default queue priority.
+    module ClassMethods
+      mattr_accessor(:default_priority)
+
+      # Specifies the priority of the queue to create the job with.
+      #
+      #   class PublishToFeedJob < ActiveJob::Base
+      #     queue_with_priority 50
+      #
+      #     def perform(post)
+      #       post.to_feed!
+      #     end
+      #   end
+      #
+      # Specify either an argument or a block.
+      def queue_with_priority(priority=nil, &block)
+        if block_given?
+          self.priority = block
+        else
+          self.priority = priority
+        end
+      end
+    end
+
+    included do
+      class_attribute :priority, instance_accessor: false
+
+      self.priority = default_priority
+    end
+
+    # Returns the priority that the job will be created with
+    def priority
+      if @priority.is_a?(Proc)
+        @priority = instance_exec(&@priority)
+      end
+      @priority
+    end
+
+  end
+end
diff --git a/activejob/test/cases/queue_priority_test.rb b/activejob/test/cases/queue_priority_test.rb
new file mode 100644
index 0000000000..ca17b51dad
--- /dev/null
+++ b/activejob/test/cases/queue_priority_test.rb
@@ -0,0 +1,47 @@
+require 'helper'
+require 'jobs/hello_job'
+
+class QueuePriorityTest < ActiveSupport::TestCase
+  test 'priority unset by default' do
+    assert_equal nil, HelloJob.priority
+  end
+
+  test 'uses given priority' do
+    original_priority = HelloJob.priority
+
+    begin
+      HelloJob.queue_with_priority 90
+      assert_equal 90, HelloJob.new.priority
+    ensure
+      HelloJob.priority = original_priority
+    end
+  end
+
+  test 'evals block given to priority to determine priority' do
+    original_priority = HelloJob.priority
+
+    begin
+      HelloJob.queue_with_priority { 25 }
+      assert_equal 25, HelloJob.new.priority
+    ensure
+      HelloJob.priority = original_priority
+    end
+  end
+
+  test 'can use arguments to determine priority in priority block' do
+    original_priority = HelloJob.priority
+
+    begin
+      HelloJob.queue_with_priority { self.arguments.first=='1' ? 99 : 11 }
+      assert_equal 99, HelloJob.new('1').priority
+      assert_equal 11, HelloJob.new('3').priority
+    ensure
+      HelloJob.priority = original_priority
+    end
+  end
+
+  test 'uses priority passed to #set' do
+    job = HelloJob.set(priority: 123).perform_later
+    assert_equal 123, job.priority
+  end
+end
diff --git a/activejob/test/integration/queuing_test.rb b/activejob/test/integration/queuing_test.rb
index 125ba54302..e435ed4aa6 100644
--- a/activejob/test/integration/queuing_test.rb
+++ b/activejob/test/integration/queuing_test.rb
@@ -84,4 +84,16 @@ class QueuingTest < ActiveSupport::TestCase
       I18n.locale = :en
     end
   end
+
+  test 'should run job with higher priority first' do
+    skip unless adapter_is?(:delayed_job, :que)
+
+    wait_until = Time.now + 3.seconds
+    TestJob.set(wait_until: wait_until, priority: 20).perform_later "#{@id}.1"
+    TestJob.set(wait_until: wait_until, priority: 10).perform_later "#{@id}.2"
+    wait_for_jobs_to_finish_for(10.seconds)
+    assert job_executed "#{@id}.1"
+    assert job_executed "#{@id}.2"
+    assert job_executed_at("#{@id}.2") < job_executed_at("#{@id}.1")
+  end
 end
diff --git a/activejob/test/support/integration/test_case_helpers.rb b/activejob/test/support/integration/test_case_helpers.rb
index 39aee6d407..8319d09520 100644
--- a/activejob/test/support/integration/test_case_helpers.rb
+++ b/activejob/test/support/integration/test_case_helpers.rb
@@ -42,8 +42,12 @@ module TestCaseHelpers
       end
     end
 
-    def job_executed
-      Dummy::Application.root.join("tmp/#{@id}").exist?
+    def job_executed(id=@id)
+      Dummy::Application.root.join("tmp/#{id}").exist?
+    end
+
+    def job_executed_at(id=@id)
+      File.new(Dummy::Application.root.join("tmp/#{id}")).ctime
     end
 
     def job_output
diff --git a/activejob/test/support/que/inline.rb b/activejob/test/support/que/inline.rb
index 0232da1370..0950e52d28 100644
--- a/activejob/test/support/que/inline.rb
+++ b/activejob/test/support/que/inline.rb
@@ -6,6 +6,7 @@ Que::Job.class_eval do
     if args.last.is_a?(Hash)
       options = args.pop
       options.delete(:run_at)
+      options.delete(:priority)
       args << options unless options.empty?
     end
     self.run(*args)