Refactored jobs:work, added jobs:clear.

  - added Rake descriptions
  - factored jobs:work into Delayed::Worker for reuse in scripts
  - updated the README to suggest using Delayed::Worker.new.start

README.textile

@@ -14,7 +14,7 @@ It is a direct extraction from Shopify where the job table is responsible for a
 
 h2. Changes
 
-* 1.6 Renamed locked_until to locked_at. We now store when we start a given task instead of how long it will be locked by the worker. This allows us to get a reading on how long a task took to execute.                    
+* 1.6 Renamed locked_until to locked_at. We now store when we start a given job instead of how long it will be locked by the worker. This allows us to get a reading on how long a job took to execute.                    
 * 1.5 Job runners can now be run in parallel. Two new database columns are needed: locked_until and locked_by. This allows us to use pessimistic locking, which enables us to run as many worker processes as we need to speed up queue processing.
 * 1.0 Initial release
 
@@ -56,48 +56,19 @@ This will simply create a Delayed::PerformableMethod job in the jobs table which
 which are stored as their text representation and loaded from the database fresh when the job is actually run later.
 
 
-h2. Running the tasks
+h2. Running the jobs
 
-You can invoke @rake jobs:work@ which will start working off jobs. You can cancel the rake task by @CTRL-C@. 
+You can invoke @rake jobs:work@ which will start working off jobs. You can cancel the rake task with @CTRL-C@. 
 
-At Shopify we run the the tasks from a simple script/job_runner which is being invoked by runnit: 
+You can also run by writing a simple @script/job_runner@, and invoking it externally:
 
 <pre><code>
   #!/usr/bin/env ruby
   require File.dirname(__FILE__) + '/../config/environment'
 
-  SLEEP = 5
-
-  trap('TERM') { puts 'Exiting...'; $exit = true }
-  trap('INT')  { puts 'Exiting...'; $exit = true }
-
-  puts "*** Starting job worker #{Delayed::Job.worker_name}"
-
-  begin
-
-    loop do  
-      result = nil                                 
-
-      realtime = Benchmark.realtime do  
-        result = Delayed::Job.work_off      
-      end                                                                          
-
-      count = result.sum
-
-      break if $exit
-
-      if count.zero? 
-        sleep(SLEEP)
-        puts 'Waiting for more jobs...'
-      else
-        status = "#{count} jobs processed at %.4f j/s, %d failed ..." % [count / realtime, result.last]
-        RAILS_DEFAULT_LOGGER.info status
-        puts status
-      end
-
-      break if $exit
-    end
-  ensure 
-    Delayed::Job.clear_locks!
-  end  
+  Delayed::Worker.new.start  
 </code></pre>
+
+h3. Cleaning up
+
+You can invoke @rake jobs:clear@ to delete all jobs in the queue.

lib/delayed/worker.rb

@@ -0,0 +1,39 @@
+module Delayed
+  class Worker
+    SLEEP = 5
+
+    def initialize(options={})
+      @quiet = options[:quiet]
+    end
+
+    def start
+      puts "*** Starting job worker #{Delayed::Job.worker_name}" unless @quiet
+
+      trap('TERM') { puts 'Exiting...' unless @quiet; $exit = true }
+      trap('INT')  { puts 'Exiting...' unless @quiet; $exit = true }
+
+      loop do      
+        result = nil                                 
+
+        realtime = Benchmark.realtime do  
+          result = Delayed::Job.work_off      
+        end                                                                          
+
+        count = result.sum
+
+        break if $exit
+
+        if count.zero? 
+          sleep(SLEEP)
+          puts 'Waiting for more jobs...' unless @quiet
+        else
+          status = "#{count} jobs processed at %.4f j/s, %d failed ..." % [count / realtime, result.last]
+          RAILS_DEFAULT_LOGGER.info status
+          puts status unless @quiet
+        end
+
+        break if $exit
+      end
+    end
+  end
+end

tasks/jobs.rake

@@ -1,36 +1,11 @@
 namespace :jobs do
+  desc "Clear the delayed_job queue."
+  task :clear => :environment do
+    Delayed::Job.delete_all
+  end
 
-               
+  desc "Start a delayed_job worker."
   task :work => :environment do 
-
-    puts "*** Starting job worker #{Delayed::Job.worker_name}"
-
-    SLEEP = 5
-
-    trap('TERM') { puts 'Exiting...'; $exit = true }
-    trap('INT')  { puts 'Exiting...'; $exit = true }
-
-    loop do      
-      result = nil                                 
-
-      realtime = Benchmark.realtime do  
-        result = Delayed::Job.work_off      
-      end                                                                          
-
-      count = result.sum
-
-      break if $exit
-
-      if count.zero? 
-        sleep(SLEEP)
-        puts 'Waiting for more jobs...'
-      else
-        status = "#{count} jobs processed at %.4f j/s, %d failed ..." % [count / realtime, result.last]
-        RAILS_DEFAULT_LOGGER.info status
-        puts status
-      end
-
-      break if $exit
-    end
+    Delayed::Worker.new.start
   end
-end
+end