Implement target selection, autodiscovery via aggregator, implement listTargets

cmd/aggregator/main.go

@@ -27,16 +27,21 @@ func main() {
 	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 	defer stop()
 
-	merger := NewMerger()
-	cache := NewCache(merger, *source)
-	go cache.Run(ctx)
-
+	var collectorAddrs []string
 	for _, addr := range strings.Split(*collectors, ",") {
 		addr = strings.TrimSpace(addr)
-		if addr == "" {
-			continue
+		if addr != "" {
+			collectorAddrs = append(collectorAddrs, addr)
 		}
-		sub := NewCollectorSub(addr, merger)
+	}
+
+	merger := NewMerger()
+	cache := NewCache(merger, *source)
+	registry := NewTargetRegistry(collectorAddrs)
+	go cache.Run(ctx)
+
+	for _, addr := range collectorAddrs {
+		sub := NewCollectorSub(addr, merger, registry)
 		go sub.Run(ctx)
 		log.Printf("aggregator: subscribing to collector %s", addr)
 	}
@@ -46,7 +51,7 @@ func main() {
 		log.Fatalf("aggregator: failed to listen on %s: %v", *listen, err)
 	}
 	grpcServer := grpc.NewServer()
-	pb.RegisterLogtailServiceServer(grpcServer, NewServer(cache, *source))
+	pb.RegisterLogtailServiceServer(grpcServer, NewServer(cache, *source, registry))
 
 	go func() {
 		log.Printf("aggregator: gRPC listening on %s (source=%s)", *listen, *source)