func getNewCaches(localStates peer.CRStatesThreadsafe, monitorConfigTS TrafficMonitorConfigMapThreadsafe) map[enum.CacheName]struct{} {
	monitorConfig := monitorConfigTS.Get()
	caches := map[enum.CacheName]struct{}{}
	for cacheName := range localStates.GetCaches() {
		// ONLINE and OFFLINE caches are not polled.
		// TODO add a function IsPolled() which can be called by this and the monitorConfig func which sets the polling, to prevent updating in one place breaking the other.
		if ts, ok := monitorConfig.TrafficServer[string(cacheName)]; !ok || ts.Status == "ONLINE" || ts.Status == "OFFLINE" {
			continue
		}
		caches[cacheName] = struct{}{}
	}
	return caches
}
// TODO timing, and determine if the case, or its internal `for`, should be put in a goroutine
// TODO determine if subscribers take action on change, and change to mutexed objects if not.
func monitorConfigListen(monitorConfigTS TrafficMonitorConfigMapThreadsafe, monitorConfigPollChan <-chan to.TrafficMonitorConfigMap, localStates peer.CRStatesThreadsafe, statUrlSubscriber chan<- poller.HttpPollerConfig, healthUrlSubscriber chan<- poller.HttpPollerConfig, peerUrlSubscriber chan<- poller.HttpPollerConfig, cfg config.Config, staticAppData StaticAppData) {
	for {
		select {
		case monitorConfig := <-monitorConfigPollChan:
			monitorConfigTS.Set(monitorConfig)
			healthUrls := map[string]string{}
			statUrls := map[string]string{}
			peerUrls := map[string]string{}
			caches := map[string]string{}

			for _, srv := range monitorConfig.TrafficServer {
				caches[srv.HostName] = srv.Status

				cacheName := enum.CacheName(srv.HostName)

				if srv.Status == "ONLINE" {
					localStates.SetCache(cacheName, peer.IsAvailable{IsAvailable: true})
					continue
				}
				if srv.Status == "OFFLINE" {
					localStates.SetCache(cacheName, peer.IsAvailable{IsAvailable: false})
					continue
				}
				// seed states with available = false until our polling cycle picks up a result
				if _, exists := localStates.Get().Caches[cacheName]; !exists {
					localStates.SetCache(cacheName, peer.IsAvailable{IsAvailable: false})
				}

				url := monitorConfig.Profile[srv.Profile].Parameters.HealthPollingURL
				r := strings.NewReplacer(
					"${hostname}", srv.FQDN,
					"${interface_name}", srv.InterfaceName,
					"application=system", "application=plugin.remap",
					"application=", "application=plugin.remap",
				)
				url = r.Replace(url)
				healthUrls[srv.HostName] = url
				r = strings.NewReplacer("application=plugin.remap", "application=")
				url = r.Replace(url)
				statUrls[srv.HostName] = url
			}

			for _, srv := range monitorConfig.TrafficMonitor {
				if srv.HostName == staticAppData.Hostname {
					continue
				}
				if srv.Status != "ONLINE" {
					continue
				}
				// TODO: the URL should be config driven. -jse
				url := fmt.Sprintf("http://%s:%d/publish/CrStates?raw", srv.IP, srv.Port)
				peerUrls[srv.HostName] = url
			}

			statUrlSubscriber <- poller.HttpPollerConfig{Urls: statUrls, Interval: cfg.CacheStatPollingInterval}
			healthUrlSubscriber <- poller.HttpPollerConfig{Urls: healthUrls, Interval: cfg.CacheHealthPollingInterval}
			peerUrlSubscriber <- poller.HttpPollerConfig{Urls: peerUrls, Interval: cfg.PeerPollingInterval}

			for cacheName := range localStates.GetCaches() {
				if _, exists := monitorConfig.TrafficServer[string(cacheName)]; !exists {
					log.Warnf("Removing %s from localStates", cacheName)
					localStates.DeleteCache(cacheName)
				}
			}

			// TODO because there are multiple writers to localStates.DeliveryService, there is a race condition, where MonitorConfig (this func) and HealthResultManager could write at the same time, and the HealthResultManager could overwrite a delivery service addition or deletion here. Probably the simplest and most performant fix would be a lock-free algorithm using atomic compare-and-swaps.
			for _, ds := range monitorConfig.DeliveryService {
				// since caches default to unavailable, also default DS false
				if _, exists := localStates.Get().Deliveryservice[enum.DeliveryServiceName(ds.XMLID)]; !exists {
					localStates.SetDeliveryService(enum.DeliveryServiceName(ds.XMLID), peer.Deliveryservice{IsAvailable: false, DisabledLocations: []enum.CacheName{}}) // important to initialize DisabledLocations, so JSON is `[]` not `null`
				}
			}
			for ds, _ := range localStates.Get().Deliveryservice {
				if _, exists := monitorConfig.DeliveryService[string(ds)]; !exists {
					localStates.DeleteDeliveryService(ds)
				}
			}
		}
	}
}
// TODO timing, and determine if the case, or its internal `for`, should be put in a goroutine
// TODO determine if subscribers take action on change, and change to mutexed objects if not.
func monitorConfigListen(monitorConfigTS TrafficMonitorConfigMapThreadsafe, monitorConfigPollChan <-chan to.TrafficMonitorConfigMap, localStates peer.CRStatesThreadsafe, statUrlSubscriber chan<- poller.HttpPollerConfig, healthUrlSubscriber chan<- poller.HttpPollerConfig, peerUrlSubscriber chan<- poller.HttpPollerConfig) {
	for {
		select {
		case monitorConfig := <-monitorConfigPollChan:
			monitorConfigTS.Set(monitorConfig)
			healthUrls := map[string]string{}
			statUrls := map[string]string{}
			peerUrls := map[string]string{}
			caches := map[string]string{}

			for _, srv := range monitorConfig.TrafficServer {
				caches[srv.HostName] = srv.Status

				if srv.Status == "ONLINE" {
					localStates.SetCache(srv.HostName, peer.IsAvailable{IsAvailable: true})
					continue
				}
				if srv.Status == "OFFLINE" {
					localStates.SetCache(srv.HostName, peer.IsAvailable{IsAvailable: false})
					continue
				}
				// seed states with available = false until our polling cycle picks up a result
				if _, exists := localStates.Get().Caches[srv.HostName]; !exists {
					localStates.SetCache(srv.HostName, peer.IsAvailable{IsAvailable: false})
				}

				url := monitorConfig.Profile[srv.Profile].Parameters.HealthPollingURL
				r := strings.NewReplacer(
					"${hostname}", srv.FQDN,
					"${interface_name}", srv.InterfaceName,
					"application=system", "application=plugin.remap",
					"application=", "application=plugin.remap",
				)
				url = r.Replace(url)
				healthUrls[srv.HostName] = url
				r = strings.NewReplacer("application=plugin.remap", "application=")
				url = r.Replace(url)
				statUrls[srv.HostName] = url
			}

			for _, srv := range monitorConfig.TrafficMonitor {
				if srv.Status != "ONLINE" {
					continue
				}
				// TODO: the URL should be config driven. -jse
				url := fmt.Sprintf("http://%s:%d/publish/CrStates?raw", srv.IP, srv.Port)
				peerUrls[srv.HostName] = url
			}

			statUrlSubscriber <- poller.HttpPollerConfig{Urls: statUrls, Interval: defaultCacheStatPollingInterval}
			healthUrlSubscriber <- poller.HttpPollerConfig{Urls: healthUrls, Interval: defaultCacheHealthPollingInterval}
			peerUrlSubscriber <- poller.HttpPollerConfig{Urls: peerUrls, Interval: defaultPeerPollingInterval}

			for k := range localStates.GetCaches() {
				if _, exists := monitorConfig.TrafficServer[k]; !exists {
					log.Warnf("Removing %s from localStates", k)
					localStates.DeleteCache(k)
				}
			}

			addStateDeliveryServices(monitorConfig, localStates.Get().Deliveryservice)
		}
	}
}