Fix big spikes in usage_time metric

The StartupTime of an app can be 0 when the app was (automatically)
stopped before the app has started up. This resulted in the UsageTime
becoming the current time in milliseconds.

Author: LEDfan

src/main/java/eu/openanalytics/containerproxy/service/ProxyService.java

@@ -298,10 +298,12 @@ public void stopProxy(Proxy proxy, boolean async, boolean ignoreAccessControl) {
 				backend.stopProxy(proxy);
 				logService.detach(proxy);
 				log.info(String.format("Proxy released [user: %s] [spec: %s] [id: %s]", proxy.getUserId(), proxy.getSpec().getId(), proxy.getId()));
-				applicationEventPublisher.publishEvent(new ProxyStopEvent(this, proxy.getUserId(),
-						proxy.getSpec().getId(),
-						Duration.ofMillis(System.currentTimeMillis() - proxy.getStartupTimestamp())));
-
+				if (proxy.getStartupTimestamp() == 0) {
+					applicationEventPublisher.publishEvent(new ProxyStopEvent(this, proxy.getUserId(), proxy.getSpec().getId(), null));
+				} else {
+					applicationEventPublisher.publishEvent(new ProxyStopEvent(this, proxy.getUserId(), proxy.getSpec().getId(),
+							Duration.ofMillis(System.currentTimeMillis() - proxy.getStartupTimestamp())));
+				}
 			} catch (Exception e){
 				log.error("Failed to release proxy " + proxy.getId(), e);
 			}

src/main/java/eu/openanalytics/containerproxy/stat/impl/Micrometer.java

@@ -126,7 +126,9 @@ public void onProxyStartEvent(ProxyStartEvent event) {
     public void onProxyStopEvent(ProxyStopEvent event) {
         logger.debug("ProxyStopEvent [user: {}, usageTime: {}]", event.getUserId(), event.getUsageTime());
         registry.counter("appStops", "spec.id", event.getSpecId()).increment();
-        registry.timer("usageTime", "spec.id", event.getSpecId()).record(event.getUsageTime());
+        if (event.getUsageTime() != null) {
+            registry.timer("usageTime", "spec.id", event.getSpecId()).record(event.getUsageTime());
+        }
     }
 
     @EventListener