prevent cron from being kicked twice in multiple schedulers

lib/resque/scheduler.rb

@@ -51,9 +51,13 @@ def load_schedule!
         Resque.schedule.each do |name, config|
           log! "Scheduling #{name} "
           if !config['cron'].nil? && config['cron'].length > 0
-            rufus_scheduler.cron config['cron'] do
-              log! "queuing #{config['class']} (#{name})"
-              enqueue_from_config(config)
+            rufus_scheduler.cron config['cron'] do |c|
+              if Resque.cron_not_done?(name, c.last)
+                log! "queuing #{config['class']} (#{name})"
+                enqueue_from_config(config)
+              else
+                log! "cron already done in other shcduler for #{config['class']} (#{name}) - skipping"
+              end
             end
           else
             log! "no cron found for #{config['class']} (#{name}) - skipping"
@@ -135,4 +139,4 @@ def log(msg)
 
   end
 
-end
+end

lib/resque_scheduler.rb

@@ -109,9 +109,12 @@ def next_item_for_timestamp(timestamp)
     item
   end
 
+  def cron_not_done?(name, timestamp)
+    redis.getset("cron_#{name}", timestamp.to_i).to_s != timestamp.to_i.to_s
+  end
 end
 
 Resque.extend ResqueScheduler
 Resque::Server.class_eval do
   include ResqueScheduler::Server
-end
+end