Merge pull request #3035 from hashicorp/kw/fix-duplicate-listener

fix(aws-alb): DuplicateListener on 2nd `up`

.changelog/3035.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+plugin/alb: Handle DuplicateListener errors from aws-alb releaser
+```

builtin/aws/alb/releaser.go

@@ -372,15 +372,15 @@ func (r *Releaser) resourceListenerCreate(
 
  tgs := []*elbv2.TargetGroupTuple{
  {
- TargetGroupArn: &target.Arn,
+ TargetGroupArn: aws.String(target.Arn),
  Weight: aws.Int64(100),
  },
  }
 
  if shouldCreateListener {
  // create the listener to forward traffic to the target group
  lo, err := elbsrv.CreateListener(&elbv2.CreateListenerInput{
- LoadBalancerArn: &lbState.Arn,
+ LoadBalancerArn: aws.String(lbState.Arn),
  Port: aws.Int64(port),
  Protocol: aws.String(protocol),
  Certificates: certs,
@@ -394,6 +394,57 @@ func (r *Releaser) resourceListenerCreate(
  },
  })
  if err != nil {
+ log.Warn("error creating listener", "error", err)
+ if aerr, ok := err.(awserr.Error); ok {
+ // CreateListener is idempotent, but if params change, such as `DefaultActions`,
+ // it will return a DuplicateListener error
+ switch aerr.Code() {
+ case elbv2.ErrCodeDuplicateListenerException:
+ // if DuplicateListener, we actually want to ModifyListener to use
+ // the newly created TargetGroup & Target pair.
+ //
+ // this requires us to fetch the listener ARN from the load balancer
+ log.Info("duplicate listener found, attempting to modify listener")
+ dlo, err := elbsrv.DescribeListeners(&elbv2.DescribeListenersInput{
+ LoadBalancerArn: aws.String(lbState.Arn),
+ })
+ if err != nil {
+ return err
+ }
+
+ // find the listener on our port
+ for _, ln := range dlo.Listeners {
+ if *ln.Port == port {
+ listener = ln
+ }
+ }
+
+ mlo, err := elbsrv.ModifyListener(&elbv2.ModifyListenerInput{
+ ListenerArn: listener.ListenerArn,
+ Port: aws.Int64(port),
+ Protocol: aws.String(protocol),
+ Certificates: certs,
+ DefaultActions: []*elbv2.Action{
+ {
+ ForwardConfig: &elbv2.ForwardActionConfig{
+ TargetGroups: tgs,
+ },
+ Type: aws.String("forward"),
+ },
+ },
+ })
+ if err != nil {
+ return err
+ }
+
+ listener = mlo.Listeners[0]
+ state.Arn = *listener.ListenerArn
+
+ log.Info("modified listener", "arn", state.Arn)
+ // exit
+ return nil
+ }
+ }
  return err
  }
  listener = lo.Listeners[0]