Use global capacity algorithm in serializer

The task manager was doing work to compute currently consumed
capacity, this is moved into the manager and applied in the
same form to the instance group list.

awx/api/serializers.py

@@ -3564,6 +3564,7 @@ class InstanceSerializer(BaseSerializer):
 
 class InstanceGroupSerializer(BaseSerializer):
 
+    consumed_capacity = serializers.SerializerMethodField()
     percent_capacity_remaining = serializers.SerializerMethodField()
     jobs_running = serializers.SerializerMethodField()
     instances = serializers.SerializerMethodField()
@@ -3581,17 +3582,37 @@ class InstanceGroupSerializer(BaseSerializer):
             res['controller'] = self.reverse('api:instance_group_detail', kwargs={'pk': obj.controller_id})
         return res
 
+    def get_jobs_qs(self):
+        # Store running jobs queryset in context, so it will be shared in ListView
+        if 'running_jobs' not in self.context:
+            self.context['running_jobs'] = UnifiedJob.objects.filter(
+                status__in=('running', 'waiting'))
+        return self.context['running_jobs']
+
+    def get_capacity_dict(self):
+        # Store capacity values (globally computed) in the context
+        if 'capacity_map' not in self.context:
+            ig_qs = None
+            if self.parent:  # Is ListView:
+                ig_qs = self.parent.instance
+            self.context['capacity_map'] = InstanceGroup.objects.capacity_values(
+                qs=ig_qs, tasks=self.get_jobs_qs(), breakdown=True)
+        return self.context['capacity_map']
+
     def get_consumed_capacity(self, obj):
-        return obj.consumed_capacity
+        return self.get_capacity_dict()[obj.name]['consumed_capacity']
 
     def get_percent_capacity_remaining(self, obj):
-        if not obj.capacity or obj.consumed_capacity == obj.capacity:
+        if not obj.capacity:
             return 0.0
         else:
-            return float("{0:.2f}".format(((float(obj.capacity) - float(obj.consumed_capacity)) / (float(obj.capacity))) * 100))
+            return float("{0:.2f}".format(
+                ((float(obj.capacity) - float(self.get_consumed_capacity(obj))) / (float(obj.capacity))) * 100)
+            )
 
     def get_jobs_running(self, obj):
-        return UnifiedJob.objects.filter(instance_group=obj, status__in=('running', 'waiting',)).count()
+        jobs_qs = self.get_jobs_qs()
+        return sum(1 for job in jobs_qs if job.instance_group_id == obj.id)
 
     def get_instances(self, obj):
         return obj.instances.count()