Merge pull request #98 from ContainerSolutions/generation-state-cleanup

removing generation state for deleted resources from memory

Author: csviri

operator-framework/src/main/java/com/github/containersolutions/operator/processing/EventScheduler.java

@@ -64,13 +64,19 @@ void scheduleEventFromApi(CustomResourceEvent event) {
         try {
             lock.lock();
             log.debug("Scheduling event from Api: {}", event);
-            if (event.getResource().getMetadata().getDeletionTimestamp() != null && event.getAction() == Action.DELETED) {
-                // Note that we always use finalizers, we want to process delete event just in corner case,
-                // when we are not able to add finalizer (lets say because of optimistic locking error, and the resource was deleted instantly).
-                // We want to skip in case of finalizer was there since we don't want to execute delete method always at least 2x,
-                // which would be the result if we don't skip here. (there is no deletion timestamp if resource deleted without finalizer.)
-                log.debug("Skipping delete event since deletion timestamp is present on resource, so finalizer was in place.");
-                return;
+            if (event.getAction() == Action.DELETED) {
+                // This removes data from memory for deleted resource (prevent memory leak basically).
+                // Its quite interesting that this is always sufficient here (no finalizer or other mechanism needs to be involved).
+                // Thus, if operator is running we get DELETE the event, if not the memory is already gone anyways.
+                eventStore.removeLastGenerationForDeletedResource(event.resourceUid());
+                if (event.getResource().getMetadata().getDeletionTimestamp() != null) {
+                    // Note that we always use finalizers, we want to process delete event just in corner case,
+                    // when we are not able to add finalizer (lets say because of optimistic locking error, and the resource was deleted instantly).
+                    // We want to skip in case of finalizer was there since we don't want to execute delete method always at least 2x,
+                    // which would be the result if we don't skip here. (there is no deletion timestamp if resource deleted without finalizer.)
+                    log.debug("Skipping delete event since deletion timestamp is present on resource, so finalizer was in place.");
+                    return;
+                }
             }
             // In case of generation aware processing, we want to replace this even if generation not increased,
             // to have the most recent copy of the event.

operator-framework/src/main/java/com/github/containersolutions/operator/processing/EventStore.java

@@ -51,4 +51,8 @@ public boolean hasLargerGenerationThanLastStored(CustomResourceEvent event) {
     public Long getLastStoredGeneration(CustomResourceEvent event) {
         return lastGeneration.get(event.getResource().getMetadata().getUid());
     }
+
+    public void removeLastGenerationForDeletedResource(String uuid) {
+        lastGeneration.remove(uuid);
+    }
 }