[Question] possible without tls

[sstarcher]

I'm attempting to terminate tls before hitting the grpc/rest gateway so I disabled the TLS certs in the code base and turned on grpc.WithInsecure, but I always end up with
{"error":"transport is closing","code":14}%

[sstarcher]

And to answer my question this is due to the http.Server upgrading to http2

[sstarcher]

That seems to be the case for http directly hitting the gateway, but I also get the same issue when using a grpc client which should already be http2.

[JesseYan]

The same problem, anyone can explain how to fix it in other ways?

[cy-zheng]

Same question, is there any way to run grpc server and grpc gateway in a port without tls?

[Stoakes]

Hi,

I also had to get it working without TLS, so I adapted the code. You can find my version here: https://github.com/Stoakes/grpc-gateway-example

[nikkolasg]

So youre version use cmux apparently and set back regular HTTP connection to use HTTP 1 for non-gRPC connections.
While that's a working solution, that does not solve the udnerlying problem...

I've dig up a little bit by re-creating a small example and what I found is that in the grpcHandlerFunc , the function never enters the "grpc section" because the content type is empty while it should be "application/grpc" ).

After that, I tried to run a basic basic gRPC example starting from a http.ServeMux but I could not make it work, even when explicitely using http2.

Any ideas ?

[nikkolasg]

Just for reference everything is explained here grpc/grpc-go#555

In short, it's not directly possible for now and there's a few options described in this post (including cmux's solution like @Stoakes ): https://medium.com/@thatcher/why-choose-between-grpc-and-rest-bc0d351f2f84

[adamcohen]

I used the details from grpc/grpc-go#555 for a workaround:

import (
  "context"
  "net/http"

  "golang.org/x/net/http2"
  "golang.org/x/net/http2/h2c"

  "github.com/grpc-ecosystem/grpc-gateway/runtime"

  "google.golang.org/grpc"
  "google.golang.org/grpc/credentials"

  pb "github.com/philips/grpc-gateway-example/echopb"
)

func grpcHandlerFunc(grpcServer *grpc.Server, otherHandler http.Handler) http.Handler {
  return h2c.NewHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    if r.ProtoMajor == 2 && strings.Contains(r.Header.Get("Content-Type"), "application/grpc") {
      grpcServer.ServeHTTP(w, r)
    } else {
      otherHandler.ServeHTTP(w, r)
    }
  }), &http2.Server{})
}

func StartServer() {
  grpcServer := grpc.NewServer()
  pb.RegisterEchoServiceServer(grpcServer, newServer())

  mux := http.NewServeMux()
  gwmux := runtime.NewServeMux()

  ctx := context.Background()

  dopts := []grpc.DialOption{grpc.WithInsecure()}

  err = pb.RegisterEchoServiceHandlerFromEndpoint(ctx, gwmux, "localhost:8020", dopts)

  http.ListenAndServe(":8020", grpcHandlerFunc(grpcServer, mux))
}

[mydnight]

@adamcohen
Thanks, I was encountering the same issue and it's been driving me nuts for the last day. This solution works wonderfully!

-   mux := http.NewServeMux()
  gwmux := runtime.NewServeMux()

  ctx := context.Background()

  dopts := []grpc.DialOption{grpc.WithInsecure()}

  err = pb.RegisterEchoServiceHandlerFromEndpoint(ctx, gwmux, "localhost:8020", dopts)

-   http.ListenAndServe(":8020", grpcHandlerFunc(grpcServer, mux))
+   http.ListenAndServe(":8020", grpcHandlerFunc(grpcServer, gwmux))

Hey @adamcohen, as per my example above, why do we need the mux here? Couldn't we just use gwmux?

[adamcohen]

Hey @adamcohen, as per my example above, why do we need the mux here? Couldn't we just use gwmux?

@kadenlnelson possibly - I think there was a reason why I needed the separate mux, but I can't remember now.

Hey @adamcohen, as per my example above, why do we need the mux here? Couldn't we just use gwmux?

@kadenlnelson possibly - I think there was a reason why I needed the separate mux, but I can't remember now.

I think the mux is used for serving the swagger ui