Batch up requests with more than 10 target group changes

aws/resource_aws_autoscaling_group.go

@@ -920,22 +920,47 @@ func resourceAwsAutoscalingGroupUpdate(d *schema.ResourceData, meta interface{})
 		add := expandStringList(ns.Difference(os).List())
 
 		if len(remove) > 0 {
-			_, err := conn.DetachLoadBalancerTargetGroups(&autoscaling.DetachLoadBalancerTargetGroupsInput{
-				AutoScalingGroupName: aws.String(d.Id()),
-				TargetGroupARNs:      remove,
-			})
-			if err != nil {
-				return fmt.Errorf("Error updating Load Balancers Target Groups for AutoScaling Group (%s), error: %s", d.Id(), err)
+			// AWS API only supports adding/removing 10 at a time
+			var batches [][]*string
+
+			batchSize := 10
+
+			for batchSize < len(remove) {
+				remove, batches = remove[batchSize:], append(batches, remove[0:batchSize:batchSize])
 			}
+			batches = append(batches, remove)
+
+			for _, batch := range batches {
+				_, err := conn.DetachLoadBalancerTargetGroups(&autoscaling.DetachLoadBalancerTargetGroupsInput{
+					AutoScalingGroupName: aws.String(d.Id()),
+					TargetGroupARNs:      batch,
+				})
+				if err != nil {
+					return fmt.Errorf("Error updating Load Balancers Target Groups for AutoScaling Group (%s), error: %s", d.Id(), err)
+				}
+			}
+
 		}
 
 		if len(add) > 0 {
-			_, err := conn.AttachLoadBalancerTargetGroups(&autoscaling.AttachLoadBalancerTargetGroupsInput{
-				AutoScalingGroupName: aws.String(d.Id()),
-				TargetGroupARNs:      add,
-			})
-			if err != nil {
-				return fmt.Errorf("Error updating Load Balancers Target Groups for AutoScaling Group (%s), error: %s", d.Id(), err)
+			batchSize := 10
+
+			var batches [][]*string
+
+			for batchSize < len(add) {
+				add, batches = add[batchSize:], append(batches, add[0:batchSize:batchSize])
+			}
+			batches = append(batches, add)
+
+			for _, batch := range batches {
+				_, err := conn.AttachLoadBalancerTargetGroups(&autoscaling.AttachLoadBalancerTargetGroupsInput{
+					AutoScalingGroupName: aws.String(d.Id()),
+					TargetGroupARNs:      batch,
+				})
+
+				if err != nil {
+					return fmt.Errorf("Error updating Load Balancers Target Groups for AutoScaling Group (%s), error: %s", d.Id(), err)
+				}
 			}
 		}
 	}