func updateIstioServiceEndpoints()

in istio/pkg/controllers/istioconnector/controller.go [259:310]
45 lines of code
12 McCabe index (conditional complexity)

func updateIstioServiceEndpoints(se *v1alpha3.ServiceEntry, action discovery.EventType, targetInst *event.InstanceEntry) error {
	targetInstanceId := targetInst.InstanceId
	newInsts := []*event.InstanceEntry{}
	var seAsMSE *event.MicroserviceEntry
	// Convert ServiceEntry back to service center service to apply changes to its service center instances
	if res := event.NewServiceEntry(se).Convert(); res == nil {
		return fmt.Errorf("failed to parse existing Istio ServiceEntry")
	} else {
		seAsMSE = res
	}
	switch discovery.EventType(action) {
	case discovery.EVT_DELETE:
		// Filter out the deleted instance
		for _, existingInst := range seAsMSE.Instances {
			if existingInst.InstanceId != targetInstanceId {
				newInsts = append(newInsts, existingInst)
			}
		}
		if len(seAsMSE.Instances) == len(newInsts) {
			log.Warnf("could not push delete for target Service Center instance id %s, instance was not found\n", targetInstanceId)
		}
		seAsMSE.Instances = newInsts
	case discovery.EVT_CREATE:
		// CREATE still requires check to determine whether the endpoint already exists; UPDATE is used in this case.
		fallthrough
	case discovery.EVT_UPDATE:
		updated := false
		for i, existingInst := range seAsMSE.Instances {
			if existingInst.InstanceId == targetInstanceId {
				// Found existing instance, update with new instance
				seAsMSE.Instances[i] = targetInst
				updated = true
				break
			}
		}
		if !updated {
			// Instance does not already exist, add as new instance
			seAsMSE.Instances = append(seAsMSE.Instances, targetInst)
		}
	}
	// Convert the microservice entry back to istio service entry; the serviceports for the changed endpoints will be regenerated appropriately by conversion logic
	var regenedSe *v1alpha3.ServiceEntry
	if res := seAsMSE.Convert(); res == nil {
		return fmt.Errorf("failed to parse changes for Istio ServiceEntry")
	} else {
		regenedSe = res.ServiceEntry
	}
	// Only take regened ports and new workloadentries, preserves rest of original serviceentry
	se.Spec.Endpoints = regenedSe.Spec.Endpoints
	se.Spec.Ports = regenedSe.Spec.Ports
	return nil
}