Make Delayed::Job.worker_name compatible with daemonizing. Display th…

…e correct pid.

lib/delayed/job.rb

@@ -24,8 +24,24 @@ class Job < ActiveRecord::Base
     # Every worker has a unique name which by default is the pid of the process.
     # There are some advantages to overriding this with something which survives worker retarts:
     # Workers can safely resume working on tasks which are locked by themselves. The worker will assume that it crashed before.
-    cattr_accessor :worker_name
-    self.worker_name = "host:#{Socket.gethostname} pid:#{Process.pid}" rescue "pid:#{Process.pid}"
+    @@worker_name = nil
+
+    def self.worker_name
+      return @@worker_name unless @@worker_name.nil?
+      "host:#{Socket.gethostname} pid:#{Process.pid}" rescue "pid:#{Process.pid}"
+    end
+
+    def self.worker_name=(val)
+      @@worker_name = val
+    end
+
+    def worker_name
+      self.class.worker_name
+    end
+
+    def worker_name=(val)
+      @@worker_name = val
+    end
 
     NextTaskSQL         = '(run_at <= ? AND (locked_at IS NULL OR locked_at < ?) OR (locked_by = ?)) AND failed_at IS NULL'
     NextTaskOrder       = 'priority DESC, run_at ASC'