go runtime_error ai_generated true

panic: grpc: Server.RegisterService found duplicate service registration for "pb.UserService"

ID: go/grpc-already-exists-duplicate-register

Also available as: JSON · Markdown · 中文
80%Fix Rate
89%Confidence
0Evidence
2024-08-14First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
google.golang.org/grpc 1.50+ active — — —

Root Cause

The same gRPC service was registered twice on one grpc.Server, often from init() functions in multiple packages or from calling RegisterXServer twice during setup.

generic

中文

同一个 gRPC 服务被注册到同一 grpc.Server 两次，通常来自多个包中的 init() 函数，或初始化时两次调用 RegisterXServer。

Workarounds

  1. 95% success 
    func RegisterAll(s *grpc.Server) {
    pb.RegisterUserServiceServer(s, &userServer{})
    pb.RegisterOrderServiceServer(s, &orderServer{})
}
// call exactly once from main
  2. 90% success 
    // delete func init() { pb.RegisterUserServiceServer(...) }
// replace with explicit call in main()

Dead Ends

Common approaches that don't work:

  1. 85% fail

    The server is left in an inconsistent state; subsequent calls may hit the wrong handler or panic again.

  2. 70% fail

    Two servers on the same listener cause bind errors or split traffic unpredictably.