feat(go): add 100k ingest hardening baseline

go/vehicle-gateway/cmd/gateway/main.go

@@ -74,7 +74,7 @@ func main() {
 			Metrics:        registry,
 			ReadBufferSize: envInt("TCP_READ_BUFFER_BYTES", 64*1024),
 			IdleTimeout:    time.Duration(envInt("TCP_IDLE_TIMEOUT_SECONDS", 180)) * time.Second,
-			MaxConnections: envInt("TCP_MAX_CONNECTIONS", 20_000),
+			MaxConnections: envInt("TCP_MAX_CONNECTIONS", 120_000),
 			PublishUnified: publishUnified,
 		})
 		if err != nil {

go/vehicle-gateway/cmd/gateway/main_test.go

@@ -46,6 +46,16 @@ func TestGatewayConfiguresIdentityLookupCacheTTL(t *testing.T) {
 	}
 }
 
+func TestGatewayDefaultsTo100KConnectionCeiling(t *testing.T) {
+	source, err := os.ReadFile("main.go")
+	if err != nil {
+		t.Fatalf("read main.go: %v", err)
+	}
+	if !strings.Contains(string(source), `envInt("TCP_MAX_CONNECTIONS", 120_000)`) {
+		t.Fatal("gateway should default TCP_MAX_CONNECTIONS to a 100K-ready ceiling")
+	}
+}
+
 func TestNATSSinkConfigFromEnvDefaultsToGoSubjects(t *testing.T) {
 	t.Setenv("NATS_URL", "nats://172.17.111.56:4222")
 

go/vehicle-gateway/cmd/load-sim/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/loadsim"
+)
+
+func main() {
+	log.SetFlags(log.LstdFlags | log.Lmicroseconds)
+	flagCfg := loadsim.RegisterFlags(flag.CommandLine)
+	if err := flag.CommandLine.Parse(os.Args[1:]); err != nil {
+		log.Fatal(err)
+	}
+	cfg, err := flagCfg.Build()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	log.Printf("load simulation started protocol=%s addr=%s connections=%d connect_rate=%d send_interval=%s duration=%s template=%s",
+		cfg.Protocol, cfg.Addr, cfg.Connections, cfg.ConnectRatePerSecond, cfg.SendInterval, cfg.Duration, cfg.Template)
+	stats, err := (loadsim.Runner{}).Run(ctx, cfg)
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Print(formatStats(stats))
+}
+
+func formatStats(stats loadsim.Stats) string {
+	return fmt.Sprintf("connections_opened=%d connections_failed=%d frames_written=%d write_errors=%d",
+		stats.ConnectionsOpened,
+		stats.ConnectionsFailed,
+		stats.FramesWritten,
+		stats.WriteErrors,
+	)
+}

go/vehicle-gateway/cmd/load-sim/main_test.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/loadsim"
+)
+
+func TestFormatStatsIncludesCapacityCounters(t *testing.T) {
+	out := formatStats(loadsim.Stats{
+		ConnectionsOpened: 10,
+		ConnectionsFailed: 2,
+		FramesWritten:     300,
+		WriteErrors:       1,
+	})
+
+	for _, want := range []string{
+		"connections_opened=10",
+		"connections_failed=2",
+		"frames_written=300",
+		"write_errors=1",
+	} {
+		if !strings.Contains(out, want) {
+			t.Fatalf("formatStats() = %q, missing %q", out, want)
+		}
+	}
+}

go/vehicle-gateway/cmd/realtime-api/main_test.go

@@ -134,6 +134,35 @@ func TestAsyncSecondaryRealtimeUpdaterDoesNotBlockPrimaryPath(t *testing.T) {
 	}
 }
 
+func TestAsyncSecondaryQueueDropDoesNotFailPrimaryUpdate(t *testing.T) {
+	env := envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, VIN: "VIN001"}
+	primary := &contextCheckingRealtimeUpdater{}
+	registry := metrics.NewRegistry()
+	updater := &asyncSecondaryRealtimeUpdater{
+		primary:   primary,
+		secondary: &contextCheckingRealtimeUpdater{},
+		queue:     make(chan envelope.FrameEnvelope, 1),
+		registry:  registry,
+	}
+	updater.queue <- envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, VIN: "VIN000"}
+
+	if err := updater.Update(context.Background(), env); err != nil {
+		t.Fatalf("Update() error = %v", err)
+	}
+	if primary.count != 1 {
+		t.Fatalf("primary updates = %d, want 1", primary.count)
+	}
+	text := registry.Render()
+	for _, want := range []string{
+		`vehicle_realtime_async_queue_total{protocol="JT808",status="dropped",store="mysql"} 1`,
+		`vehicle_realtime_async_queue_depth{protocol="JT808",store="mysql"} 1`,
+	} {
+		if !strings.Contains(text, want) {
+			t.Fatalf("async queue drop metric missing %s:\n%s", want, text)
+		}
+	}
+}
+
 func TestStoreMetricUpdaterRecordsStoreUpdateResults(t *testing.T) {
 	registry := metrics.NewRegistry()
 	env := envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, VIN: "VIN001"}