Simplify ttlEvents ListWatch

There is no reason to do the list in one goroutine and the watch in another, as the watcher just blocks on startup waiting for the list to finish and send the revision on the channel. This can be simplified to one goroutine, which lets us drop the channel and waitgroup entirely.

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>

pkg/logstructured/logstructured.go

@@ -350,26 +350,21 @@ func (l *LogStructured) deleteTTLEvent(ctx context.Context, rwMutex *sync.RWMute
 	delete(store, curEventKV.key)
 }
 
+// ttlEvents starts a goroutine to do a ListWatch on the root prefix. First it lists
+// all non-deleted keys with a page size of 1000, then it starts watching at the
+// revision returned by the initial list. Any keys that have a Lease associated with
+// them are sent into the result channel for deferred handling of TTL expiration.
 func (l *LogStructured) ttlEvents(ctx context.Context) chan *server.Event {
 	result := make(chan *server.Event)
-	lastListRevision := make(chan int64)
-	wg := sync.WaitGroup{}
-	wg.Add(2)
 
 	go func() {
-		wg.Wait()
-		close(result)
-		close(lastListRevision)
-	}()
-
-	go func() {
-		defer wg.Done()
+		defer close(result)
 
 		rev, events, err := l.log.List(ctx, "/", "", 1000, 0, false)
 		for len(events) > 0 {
 			if err != nil {
 				logrus.Errorf("TTL event list failed: %v", err)
-				break
+				return
 			}
 
 			for _, event := range events {
@@ -378,19 +373,10 @@ func (l *LogStructured) ttlEvents(ctx context.Context) chan *server.Event {
 				}
 			}
 
-			rev, events, err = l.log.List(ctx, "/", events[len(events)-1].KV.Key, 1000, rev, false)
+			_, events, err = l.log.List(ctx, "/", events[len(events)-1].KV.Key, 1000, rev, false)
 		}
-		lastListRevision <- rev
-	}()
 
-	go func() {
-		defer wg.Done()
-		revision := <-lastListRevision
-		if revision == 0 {
-			logrus.Error("TTL event watch failed to get start revision")
-			return
-		}
-		wr := l.Watch(ctx, "/", revision)
+		wr := l.Watch(ctx, "/", rev)
 		if wr.CompactRevision != 0 {
 			logrus.Errorf("TTL event watch failed: %v", server.ErrCompacted)
 			return