TRA-3903 better health endpoint for daemon mode (#471)

* Update main.go, status_controller.go, and 2 more files...

* Update status_controller.go and mizuTapperSyncer.go

agent/main.go

@@ -459,7 +459,7 @@ func startMizuTapperSyncer(ctx context.Context) (*kubernetes.MizuTapperSyncer, e
 					return
 				}
 				logger.Log.Fatalf("fatal tap syncer error: %v", syncerErr)
-			case _, ok := <-tapperSyncer.TapPodChangesOut:
+			case tapPodChangeEvent, ok := <-tapperSyncer.TapPodChangesOut:
 				if !ok {
 					logger.Log.Debug("mizuTapperSyncer pod changes channel closed, ending listener loop")
 					return
@@ -472,6 +472,7 @@ func startMizuTapperSyncer(ctx context.Context) (*kubernetes.MizuTapperSyncer, e
 				}
 				api.BroadcastToBrowserClients(serializedTapStatus)
 				providers.TapStatus.Pods = tapStatus.Pods
+				providers.ExpectedTapperAmount = tapPodChangeEvent.ExpectedTapperAmount
 			case <-ctx.Done():
 				logger.Log.Debug("mizuTapperSyncer event listener loop exiting due to context done")
 				return

agent/pkg/controllers/status_controller.go

@@ -2,7 +2,9 @@ package controllers
 
 import (
 	"encoding/json"
+	"fmt"
 	"mizuserver/pkg/api"
+	"mizuserver/pkg/config"
 	"mizuserver/pkg/holder"
 	"mizuserver/pkg/providers"
 	"mizuserver/pkg/up9"
@@ -15,6 +17,13 @@ import (
 )
 
 func HealthCheck(c *gin.Context) {
+	if config.Config.DaemonMode {
+		if providers.ExpectedTapperAmount != providers.TappersCount {
+			c.JSON(http.StatusInternalServerError, fmt.Sprintf("expecting more tappers than are actually connected (%d expected, %d connected)", providers.ExpectedTapperAmount, providers.TappersCount))
+			return
+		}
+	}
+
 	response := shared.HealthResponse{
 		TapStatus:    providers.TapStatus,
 		TappersCount: providers.TappersCount,

agent/pkg/providers/status_provider.go

@@ -19,7 +19,7 @@ var (
 	TapStatus      shared.TapStatus
 	authStatus     *models.AuthStatus
 	RecentTLSLinks = cache.New(tlsLinkRetainmentTime, tlsLinkRetainmentTime)
-
+	ExpectedTapperAmount = -1 //only relevant in daemon mode as cli manages tappers otherwise
 	tappersCountLock = sync.Mutex{}
 )
 

shared/kubernetes/mizuTapperSyncer.go

@@ -18,6 +18,7 @@ const updateTappersDelay = 5 * time.Second
 type TappedPodChangeEvent struct {
 	Added                []core.Pod
 	Removed              []core.Pod
+	ExpectedTapperAmount int
 }
 
 // MizuTapperSyncer uses a k8s pod watch to update tapper daemonsets when targeted pods are removed or created
@@ -28,6 +29,7 @@ type MizuTapperSyncer struct {
 	kubernetesProvider   *Provider
 	TapPodChangesOut     chan TappedPodChangeEvent
 	ErrorOut             chan K8sTapManagerError
+	nodeToTappedPodIPMap map[string][]string
 }
 
 type TapperSyncerConfig struct {
@@ -160,9 +162,11 @@ func (tapperSyncer *MizuTapperSyncer) updateCurrentlyTappedPods() (err error, ch
 		}
 		if len(addedPods) > 0 || len(removedPods) > 0 {
 			tapperSyncer.CurrentlyTappedPods = podsToTap
+			tapperSyncer.nodeToTappedPodIPMap = GetNodeHostToTappedPodIpsMap(tapperSyncer.CurrentlyTappedPods)
 			tapperSyncer.TapPodChangesOut <- TappedPodChangeEvent{
 				Added:                addedPods,
 				Removed:              removedPods,
+				ExpectedTapperAmount: len(tapperSyncer.nodeToTappedPodIPMap),
 			}
 			return nil, true
 		}
@@ -171,9 +175,7 @@ func (tapperSyncer *MizuTapperSyncer) updateCurrentlyTappedPods() (err error, ch
 }
 
 func (tapperSyncer *MizuTapperSyncer) updateMizuTappers() error {
-	nodeToTappedPodIPMap := GetNodeHostToTappedPodIpsMap(tapperSyncer.CurrentlyTappedPods)
+	if len(tapperSyncer.nodeToTappedPodIPMap) > 0 {
-
-	if len(nodeToTappedPodIPMap) > 0 {
 		var serviceAccountName string
 		if tapperSyncer.config.MizuServiceAccountExists {
 			serviceAccountName = ServiceAccountName
@@ -188,7 +190,7 @@ func (tapperSyncer *MizuTapperSyncer) updateMizuTappers() error {
 			tapperSyncer.config.AgentImage,
 			TapperPodName,
 			fmt.Sprintf("%s.%s.svc.cluster.local", ApiServerPodName, tapperSyncer.config.MizuResourcesNamespace),
-			nodeToTappedPodIPMap,
+			tapperSyncer.nodeToTappedPodIPMap,
 			serviceAccountName,
 			tapperSyncer.config.TapperResources,
 			tapperSyncer.config.ImagePullPolicy,
@@ -197,7 +199,7 @@ func (tapperSyncer *MizuTapperSyncer) updateMizuTappers() error {
 		); err != nil {
 			return err
 		}
-		logger.Log.Debugf("Successfully created %v tappers", len(nodeToTappedPodIPMap))
+		logger.Log.Debugf("Successfully created %v tappers", len(tapperSyncer.nodeToTappedPodIPMap))
 	} else {
 		if err := tapperSyncer.kubernetesProvider.RemoveDaemonSet(tapperSyncer.context, tapperSyncer.config.MizuResourcesNamespace, TapperDaemonSetName); err != nil {
 			return err