lib/cloud_crowd/models/work_unit.rb in cloud-crowd-0.7.2.pre3 vs lib/cloud_crowd/models/work_unit.rb in cloud-crowd-0.7.2

@@ -42,9 +42,12 @@
         # Find the available nodes, and determine what actions we're capable
         # of running at the moment.
         available_nodes   = NodeRecord.available.to_a
         available_actions = available_nodes.map {|node| node.actions }.flatten.uniq
         filter            = "action in (#{available_actions.map{|a| "'#{a}'"}.join(',')})"
+        
+        # If there aren't any available nodes or actions don't bother doing anything.
+        return if available_nodes.empty? or available_actions.empty?
 
         # Reserve a handful of available work units.
         WorkUnit.cancel_reservations(reservation) if reservation
         return unless reservation = WorkUnit.reserve_available(:limit => RESERVATION_LIMIT, :conditions => filter)
         work_units = WorkUnit.reserved(reservation).to_a