Don't error if ASG is missing when deciding to refresh instances

Author: fiunchinho

pkg/cloud/services/autoscaling/autoscalinggroup.go

@@ -323,6 +323,9 @@ func (s *Service) CanStartASGInstanceRefresh(scope *scope.MachinePoolScope) (boo
 	describeInput := &autoscaling.DescribeInstanceRefreshesInput{AutoScalingGroupName: aws.String(scope.Name())}
 	refreshes, err := s.ASGClient.DescribeInstanceRefreshesWithContext(context.TODO(), describeInput)
 	if err != nil {
+		if awserrors.IsNotFound(err) {
+			return false, nil
+		}
 		return false, err
 	}
 	hasUnfinishedRefresh := false

pkg/cloud/services/autoscaling/autoscalinggroup_test.go

@@ -1087,6 +1087,17 @@ func TestServiceCanStartASGInstanceRefresh(t *testing.T) {
 			name:     "should return error if describe instance refresh failed",
 			wantErr:  true,
 			canStart: false,
+			expect: func(m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder) {
+				m.DescribeInstanceRefreshesWithContext(context.TODO(), gomock.Eq(&autoscaling.DescribeInstanceRefreshesInput{
+					AutoScalingGroupName: aws.String("machinePoolName"),
+				})).
+					Return(nil, awserrors.NewConflict("some error"))
+			},
+		},
+		{
+			name:     "should NOT return error if describe instance failed due to 'not found'",
+			wantErr:  false,
+			canStart: false,
 			expect: func(m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder) {
 				m.DescribeInstanceRefreshesWithContext(context.TODO(), gomock.Eq(&autoscaling.DescribeInstanceRefreshesInput{
 					AutoScalingGroupName: aws.String("machinePoolName"),