From 0be767a90a2c42a2b29184b2b149d5309c5ed1e9 Mon Sep 17 00:00:00 2001
From: Kierran McPherson <kierran.mcpherson@xero.com>
Date: Sat, 10 Nov 2018 11:02:34 +1300
Subject: [PATCH] Request AWS ASGs in batches

Signed-off-by: Kierran McPherson <kierran.mcpherson@xero.com>
---
 upup/pkg/fi/cloudup/awsup/aws_cloud.go | 47 ++++++++++++++++----------
 1 file changed, 29 insertions(+), 18 deletions(-)

diff --git a/upup/pkg/fi/cloudup/awsup/aws_cloud.go b/upup/pkg/fi/cloudup/awsup/aws_cloud.go
index 1f2e15f530139..a15a41d62dd12 100644
--- a/upup/pkg/fi/cloudup/awsup/aws_cloud.go
+++ b/upup/pkg/fi/cloudup/awsup/aws_cloud.go
@@ -491,26 +491,29 @@ func FindAutoscalingGroups(c AWSCloud, tags map[string]string) ([]*autoscaling.G
 	}
 
 	if len(asgNames) != 0 {
-		request := &autoscaling.DescribeAutoScalingGroupsInput{
-			AutoScalingGroupNames: asgNames,
-		}
-		err := c.Autoscaling().DescribeAutoScalingGroupsPages(request, func(p *autoscaling.DescribeAutoScalingGroupsOutput, lastPage bool) bool {
-			for _, asg := range p.AutoScalingGroups {
-				if !matchesAsgTags(tags, asg.Tags) {
-					// We used an inexact filter above
-					continue
-				}
-				// Check for "Delete in progress" (the only use of .Status)
-				if asg.Status != nil {
-					glog.Warningf("Skipping ASG %v (which matches tags): %v", *asg.AutoScalingGroupARN, *asg.Status)
-					continue
+		for i := 0; i < len(asgNames); i += 50 {
+			batch := asgNames[i:minInt(i+50, len(asgNames))]
+			request := &autoscaling.DescribeAutoScalingGroupsInput{
+				AutoScalingGroupNames: batch,
+			}
+			err := c.Autoscaling().DescribeAutoScalingGroupsPages(request, func(p *autoscaling.DescribeAutoScalingGroupsOutput, lastPage bool) bool {
+				for _, asg := range p.AutoScalingGroups {
+					if !matchesAsgTags(tags, asg.Tags) {
+						// We used an inexact filter above
+						continue
+					}
+					// Check for "Delete in progress" (the only use of .Status)
+					if asg.Status != nil {
+						glog.Warningf("Skipping ASG %v (which matches tags): %v", *asg.AutoScalingGroupARN, *asg.Status)
+						continue
+					}
+					asgs = append(asgs, asg)
 				}
-				asgs = append(asgs, asg)
+				return true
+			})
+			if err != nil {
+				return nil, fmt.Errorf("error listing autoscaling groups: %v", err)
 			}
-			return true
-		})
-		if err != nil {
-			return nil, fmt.Errorf("error listing autoscaling groups: %v", err)
 		}
 
 	}
@@ -518,6 +521,14 @@ func FindAutoscalingGroups(c AWSCloud, tags map[string]string) ([]*autoscaling.G
 	return asgs, nil
 }
 
+// Returns the minimum of two ints
+func minInt(a int, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
 // matchesAsgTags is used to filter an asg by tags
 func matchesAsgTags(tags map[string]string, actual []*autoscaling.TagDescription) bool {
 	for k, v := range tags {