func()

in pkg/awsutils/awsutils.go [1124:1176]

• 44 lines of code
• 6 McCabe index (conditional complexity)

func (cache *EC2InstanceMetadataCache) freeENI(eniName string, sleepDelayAfterDetach time.Duration, maxBackoffDelay time.Duration) error {
	log.Infof("Trying to free ENI: %s", eniName)

	// Find out attachment
	attachID, err := cache.getENIAttachmentID(eniName)
	if err != nil {
		if err == ErrENINotFound {
			log.Infof("ENI %s not found. It seems to be already freed", eniName)
			return nil
		}
		awsUtilsErrInc("getENIAttachmentIDFailed", err)
		log.Errorf("Failed to retrieve ENI %s attachment id: %v", eniName, err)
		return errors.Wrap(err, "FreeENI: failed to retrieve ENI's attachment id")
	}
	log.Debugf("Found ENI %s attachment id: %s ", eniName, aws.ToString(attachID))

	detachInput := &ec2.DetachNetworkInterfaceInput{
		AttachmentId: attachID,
	}

	// Retry detaching the ENI from the instance
	err = retry.NWithBackoff(retry.NewSimpleBackoff(time.Millisecond*200, maxBackoffDelay, 0.15, 2.0), maxENIEC2APIRetries, func() error {
		start := time.Now()
		_, ec2Err := cache.ec2SVC.DetachNetworkInterface(context.Background(), detachInput)
		prometheusmetrics.Ec2ApiReq.WithLabelValues("DetachNetworkInterface").Inc()
		prometheusmetrics.AwsAPILatency.WithLabelValues("DetachNetworkInterface", fmt.Sprint(ec2Err != nil), awsReqStatus(ec2Err)).Observe(msSince(start))
		if ec2Err != nil {
			checkAPIErrorAndBroadcastEvent(err, "ec2:DetachNetworkInterface")
			awsAPIErrInc("DetachNetworkInterface", ec2Err)
			prometheusmetrics.Ec2ApiErr.WithLabelValues("DetachNetworkInterface").Inc()
			log.Errorf("Failed to detach ENI %s %v", eniName, ec2Err)
			return errors.New("unable to detach ENI from EC2 instance, giving up")
		}
		log.Infof("Successfully detached ENI: %s", eniName)
		return nil
	})

	if err != nil {
		log.Errorf("Failed to detach ENI %s %v", eniName, err)
		return err
	}

	// It does take awhile for EC2 to detach ENI from instance, so we wait 2s before trying the delete.
	time.Sleep(sleepDelayAfterDetach)
	err = cache.deleteENI(eniName, maxBackoffDelay)
	if err != nil {
		awsUtilsErrInc("FreeENIDeleteErr", err)
		return errors.Wrapf(err, "FreeENI: failed to free ENI: %s", eniName)
	}

	log.Infof("Successfully freed ENI: %s", eniName)
	return nil
}