Execute PLAN_AGGREGATOR.md

cmd/aggregator/main.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"log"
+	"net"
+	"os"
+	"os/signal"
+	"strings"
+	"syscall"
+
+	pb "git.ipng.ch/ipng/nginx-logtail/proto/logtailpb"
+	"google.golang.org/grpc"
+)
+
+func main() {
+	listen     := flag.String("listen", ":9091", "gRPC listen address")
+	collectors := flag.String("collectors", "", "comma-separated collector host:port addresses")
+	source     := flag.String("source", hostname(), "name for this aggregator in responses")
+	flag.Parse()
+
+	if *collectors == "" {
+		log.Fatal("aggregator: --collectors is required")
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	merger := NewMerger()
+	cache := NewCache(merger, *source)
+	go cache.Run(ctx)
+
+	for _, addr := range strings.Split(*collectors, ",") {
+		addr = strings.TrimSpace(addr)
+		if addr == "" {
+			continue
+		}
+		sub := NewCollectorSub(addr, merger)
+		go sub.Run(ctx)
+		log.Printf("aggregator: subscribing to collector %s", addr)
+	}
+
+	lis, err := net.Listen("tcp", *listen)
+	if err != nil {
+		log.Fatalf("aggregator: failed to listen on %s: %v", *listen, err)
+	}
+	grpcServer := grpc.NewServer()
+	pb.RegisterLogtailServiceServer(grpcServer, NewServer(cache, *source))
+
+	go func() {
+		log.Printf("aggregator: gRPC listening on %s (source=%s)", *listen, *source)
+		if err := grpcServer.Serve(lis); err != nil {
+			log.Printf("aggregator: gRPC server stopped: %v", err)
+		}
+	}()
+
+	<-ctx.Done()
+	log.Printf("aggregator: shutting down")
+	grpcServer.GracefulStop()
+}
+
+func hostname() string {
+	h, err := os.Hostname()
+	if err != nil {
+		return "unknown"
+	}
+	return h
+}