test(connector): test UnixConnector reconnects after socket replacement

pkg/client/connector/unix_test.go

@@ -0,0 +1,72 @@
+package connector
+
+import (
+	"context"
+	"net"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/health"
+	healthpb "google.golang.org/grpc/health/grpc_health_v1"
+)
+
+func TestUnixConnectorReconnectsAfterSocketReplacement(t *testing.T) {
+	// Use a custom pattern instead of t.TempDir() to create a short path for the socket on macOS
+	// because it has a 104 character limit.
+	t.TempDir()
+	dir, err := os.MkdirTemp("", "uncloud-")
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		require.NoError(t, os.RemoveAll(dir))
+	})
+	socketPath := filepath.Join(dir, "uncloud.sock")
+	conn, err := NewUnixConnector(socketPath).Connect(context.Background())
+	require.NoError(t, err, "creating a gRPC channel must not require the socket to exist")
+	t.Cleanup(func() {
+		require.NoError(t, conn.Close())
+	})
+
+	client := healthpb.NewHealthClient(conn)
+	first := startHealthServer(t, socketPath)
+	requireHealthCheck(t, client)
+
+	first.Stop()
+
+	second := startHealthServer(t, socketPath)
+	t.Cleanup(second.Stop)
+	requireHealthCheck(t, client)
+}
+
+func startHealthServer(t *testing.T, socketPath string) *grpc.Server {
+	t.Helper()
+
+	listener, err := net.Listen("unix", socketPath)
+	require.NoError(t, err)
+
+	healthServer := health.NewServer()
+	healthServer.SetServingStatus("", healthpb.HealthCheckResponse_SERVING)
+	server := grpc.NewServer()
+	healthpb.RegisterHealthServer(server, healthServer)
+
+	go func() {
+		_ = server.Serve(listener)
+	}()
+
+	return server
+}
+
+func requireHealthCheck(t *testing.T, client healthpb.HealthClient) {
+	t.Helper()
+
+	require.Eventually(t, func() bool {
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+		defer cancel()
+
+		resp, err := client.Check(ctx, &healthpb.HealthCheckRequest{})
+		return err == nil && resp.Status == healthpb.HealthCheckResponse_SERVING
+	}, 15*time.Second, 100*time.Millisecond)
+}