Return 0 for staleness when the client is shutdown or when refreshes not enabled. Otherwise the metric can be misleading.

elandau · elandau · commit 5ecbbf21f13f · 2018-11-13T06:44:43.000-08:00
diff --git a/eureka-client/src/main/java/com/netflix/discovery/DiscoveryClient.java b/eureka-client/src/main/java/com/netflix/discovery/DiscoveryClient.java
@@ -1677,6 +1677,10 @@ public long getLastSuccessfulRegistryFetchTimePeriod() {
     @com.netflix.servo.annotations.Monitor(name = METRIC_REGISTRATION_PREFIX + "lastSuccessfulHeartbeatTimePeriod",
             description = "How much time has passed from last successful heartbeat", type = DataSourceType.GAUGE)
     private long getLastSuccessfulHeartbeatTimePeriodInternal() {
+        if (!clientConfig.shouldRegisterWithEureka() || isShutdown.get()) {
+            heartbeatStalenessMonitor.update(0);
+            return 0;
+        }
         long delay = getLastSuccessfulHeartbeatTimePeriod();
         heartbeatStalenessMonitor.update(computeStalenessMonitorDelay(delay));
         return delay;
@@ -1686,6 +1690,10 @@ private long getLastSuccessfulHeartbeatTimePeriodInternal() {
     @com.netflix.servo.annotations.Monitor(name = METRIC_REGISTRY_PREFIX + "lastSuccessfulRegistryFetchTimePeriod",
             description = "How much time has passed from last successful local registry update", type = DataSourceType.GAUGE)
     private long getLastSuccessfulRegistryFetchTimePeriodInternal() {
+        if (!clientConfig.shouldFetchRegistry() || isShutdown.get()) {
+            registryStalenessMonitor.update(0);
+            return 0;
+        }
         long delay = getLastSuccessfulRegistryFetchTimePeriod();
         registryStalenessMonitor.update(computeStalenessMonitorDelay(delay));
         return delay;
