Drop unnecessary expire time check in ttl event handler

handleTTLEvents already calls loadTTLEventKV which gets the most recent
event for the key while holding a lock. This is then checked to confirm
expiration before calling deleteTTLEvent.

Because it's checked before calling, we don't need to do a locked check
of the store AGAIN in deleteTTLEvent. If another goroutine updated the
key in the time between when loadTTLEventKV returned the event, and the
time that deleteTTLEvent tries to delete it, the actual Delete will fail
because the modRevision is no longer current, and the error path will
ensure that the key is re-enqueued and processed at the correct time.

Without this extra check there's not much logic left in deleteTTLEvent,
and there are no other call sites, so just move it into handleTTLEvents.

Signed-off-by: Brad Davidson <[email protected]>

pkg/logstructured/logstructured.go

@@ -325,29 +325,18 @@ func (l *LogStructured) handleTTLEvents(ctx context.Context, rwMutex *sync.RWMut
 		return true
 	}
 
-	l.deleteTTLEvent(ctx, rwMutex, queue, store, eventKV)
-	return true
-}
-
-func (l *LogStructured) deleteTTLEvent(ctx context.Context, rwMutex *sync.RWMutex, queue workqueue.DelayingInterface, store map[string]*ttlEventKV, preEventKV *ttlEventKV) {
-	logrus.Tracef("TTL delete key=%v, modRev=%v", preEventKV.key, preEventKV.modRevision)
-	_, _, _, err := l.Delete(ctx, preEventKV.key, preEventKV.modRevision)
+	logrus.Tracef("TTL delete key=%v, modRev=%v", eventKV.key, eventKV.modRevision)
+	if _, _, _, err := l.Delete(ctx, eventKV.key, eventKV.modRevision); err != nil {
+		logrus.Errorf("TTL delete trigger failed for key=%v: %v, requeuing", eventKV.key, err)
+		queue.AddAfter(eventKV.key, retryInterval)
+		return true
+	}
 
 	rwMutex.Lock()
 	defer rwMutex.Unlock()
-	curEventKV := store[preEventKV.key]
-	if expires := time.Until(preEventKV.expiredAt); expires > 0 {
-		logrus.Tracef("TTL changed for key=%v, ttl=%v, requeuing", curEventKV.key, expires)
-		queue.AddAfter(curEventKV.key, expires)
-		return
-	}
-	if err != nil {
-		logrus.Errorf("TTL delete trigger failed for key=%v: %v, requeuing", curEventKV.key, err)
-		queue.AddAfter(curEventKV.key, retryInterval)
-		return
-	}
+	delete(store, eventKV.key)
 
-	delete(store, curEventKV.key)
+	return true
 }
 
 // ttlEvents starts a goroutine to do a ListWatch on the root prefix. First it lists