harryz
harryz

Reputation: 5260

Golang grpc: how to recover the grpc server from panic?

I have a handler like this:

func (daemon *Daemon) List(item string) (map[string][]string, error) {
      panic("this is a panic")
      ...

I just want to recover this potential panic, so in my grpc server I wrote:

// Serve serves gRPC request by goroutines
func (s *ServerRPC) Serve(addr string) error {
    defer func() {
        if err := recover(); err != nil {
            glog.Errorf("Recovered from err: ", err)
        }
    }()

    l, err := net.Listen("tcp", addr)
    if err != nil {
        glog.Fatalf("Failed to listen %s: %v", addr, err)
        return err
    }

    return s.server.Serve(l)
}

But it does not capture the panic, I thought it was because my panic happened in child goroutines? If so, how can I recover my grpc server from crashing properly?

Upvotes: 5

Views: 10566

Answers (1)

Nathan Baulch
Nathan Baulch

Reputation: 20683

Take a look at the recovery interceptor in the Golang gRPC Middlewares package. It recovers from panics in the request Goroutine and returns them as an internal gRPC error.

myServer := grpc.NewServer(
    grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(
        grpc_zap.StreamServerInterceptor(zapLogger),
        grpc_auth.StreamServerInterceptor(myAuthFunction),
        grpc_recovery.StreamServerInterceptor(),
    )),
    grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(
        grpc_zap.UnaryServerInterceptor(zapLogger),
        grpc_auth.UnaryServerInterceptor(myAuthFunction),
        grpc_recovery.UnaryServerInterceptor(),
    )),
)

Upvotes: 6

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