Implement enqueue_at/enqueue_in

Delayed jobs are supported by all systems except QueueClassic.  For it I decided to raise NotImplementedError.

The inline implementation is a bit rough.

Gemfile

@@ -4,6 +4,7 @@ gemspec
 
 gem 'rake'
 gem 'resque'
+gem 'resque-scheduler'
 gem 'sidekiq'
 gem 'sucker_punch'
 gem 'delayed_job'

Gemfile.lock

@@ -47,6 +47,12 @@ GEM
       redis-namespace (~> 1.2)
       sinatra (>= 0.9.2)
       vegas (~> 0.1.2)
+    resque-scheduler (2.2.0)
+      redis (>= 3.0.0)
+      resque (>= 1.20.0, < 1.25)
+      rufus-scheduler (~> 2.0)
+    rufus-scheduler (2.0.24)
+      tzinfo (>= 0.3.22)
     sidekiq (3.0.2)
       celluloid (>= 0.15.2)
       connection_pool (>= 2.0.0)
@@ -76,5 +82,6 @@ DEPENDENCIES
   queue_classic
   rake
   resque
+  resque-scheduler
   sidekiq
   sucker_punch

lib/active_job/enqueuing.rb

@@ -13,5 +13,25 @@ module Enqueuing
     def enqueue(*args)
       queue_adapter.queue self, *Parameters.serialize(args)
     end
+
+    ##
+    # Enqueue a job to be performed at +interval+ from now.
+    #
+    #   enqueue_in(1.week, "mike")
+    #
+    # Returns truthy if a job was scheduled.
+    def enqueue_in(interval, *args)
+      enqueue_at(interval.from_now, *args)
+    end
+
+    ##
+    # Enqueue a job to be performed at an explicit point in time.
+    #
+    #   enqueue_at(Date.tomorrow.midnight, "mike")
+    #
+    # Returns truthy if a job was scheduled.
+    def enqueue_at(timestamp, *args)
+      queue_adapter.queue_at self, timestamp.to_f, *Parameters.serialize(args)
+    end
   end
 end

lib/active_job/queue_adapters/delayed_job_adapter.rb

@@ -7,8 +7,12 @@ class << self
         def queue(job, *args)
           JobWrapper.new.delay(queue: job.queue_name).perform(job, *args)
         end
+
+        def queue_at(job, timestamp, *args)
+          JobWrapper.new.delay(queue: job.queue_name, run_at: timestamp).perform(job, *args)
+        end
       end
-      
+
       class JobWrapper
         def perform(job, *args)
           job.new.perform *Parameters.deserialize(args)

lib/active_job/queue_adapters/inline_adapter.rb

@@ -5,7 +5,20 @@ class << self
         def queue(job, *args)
           job.new.perform *Parameters.deserialize(args)
         end
+
+        def queue_at(job, ts, *args)
+          # TODO better error handling?
+          Thread.new do
+            begin
+              interval = Time.now.to_f - ts
+              sleep(interval) if interval > 0
+              job.new.perform *Parameters.deserialize(args)
+            rescue => ex
+              puts ex.message
+            end
+          end
+        end
       end
     end
   end
-end
+end

lib/active_job/queue_adapters/queue_classic_adapter.rb

@@ -8,6 +8,10 @@ def queue(job, *args)
           qc_queue = QC::Queue.new(job.queue_name)
           qc_queue.enqueue("ActiveJob::QueueAdapters::QueueClassicAdapter::JobWrapper.perform", job, *args)
         end
+
+        def queue_at(job, timestamp, *args)
+          raise NotImplementedError
+        end
       end
 
       class JobWrapper

lib/active_job/queue_adapters/resque_adapter.rb

@@ -1,6 +1,7 @@
 require 'resque'
 require 'active_support/core_ext/enumerable'
 require 'active_support/core_ext/array/access'
+require 'resque_scheduler'
 
 module ActiveJob
   module QueueAdapters
@@ -9,6 +10,11 @@ class << self
         def queue(job, *args)
           Resque.enqueue JobWrapper.new(job), job, *args
         end
+
+        def queue_at(job, timestamp, *args)
+          # requires resque-scheduler
+          Resque.enqueue_at timestamp, JobWrapper.new(job), job, *args
+        end
       end
 
       class JobWrapper

lib/active_job/queue_adapters/sidekiq_adapter.rb

@@ -7,6 +7,13 @@ class << self
         def queue(job, *args)
           JobWrapper.client_push class: JobWrapper, queue: job.queue_name, args: [ job, *args ]
         end
+
+        def queue_at(job, timestamp, *args)
+          job = { class: JobWrapper, queue: job.queue_name, args: [ job, *args ], at: timestamp }
+          # Optimization to enqueue something now that is scheduled to go out now or in the past
+          job.delete(:at) if timestamp <= Time.now.to_f
+          JobWrapper.client_push(job)
+        end
       end
 
       class JobWrapper

lib/active_job/queue_adapters/sucker_punch_adapter.rb

@@ -7,6 +7,16 @@ class << self
         def queue(job, *args)
           JobWrapper.new.async.perform(job, *args)
         end
+
+        def queue_at(job, timestamp, *args)
+          secs = Time.now.to_f - timestamp
+          if secs < 1
+            # Optimization to enqueue something now that is scheduled to go out now or in the past
+            JobWrapper.new.async.perform(job, *args)
+          else
+            JobWrapper.new.async.later(secs, job, *args)
+          end
+        end
       end
 
       class JobWrapper
@@ -15,6 +25,10 @@ class JobWrapper
         def perform(job_name, *args)
           job_name.new.perform *Parameters.deserialize(args)
         end
+
+        def later(sec, job_name, *args)
+          after(sec) { p args; perform(job_name, *args) }
+        end
       end
     end
   end

test/cases/queuing_test.rb

@@ -1,5 +1,6 @@
 require 'helper'
 require 'jobs/hello_job'
+require 'active_support/core_ext/numeric/time'
 
 
 class QueuingTest < ActiveSupport::TestCase
@@ -16,4 +17,12 @@ class QueuingTest < ActiveSupport::TestCase
     HelloJob.enqueue "Jamie"
     assert_equal "Jamie says hello", $BUFFER.pop
   end
+
+  test 'run queued job later' do
+    begin
+      result = HelloJob.enqueue_at 1.second.ago, "Jamie"
+      assert_not_nil result
+    rescue NotImplementedError
+    end
+  end
 end