Add a register, so that the gRPC service can be invoked in-process to provide a HTTP server.

[hb-chen]

sometimes we don't need the HTTP gateway to be a RPC.
just convert the gRPC service to an HTTP service.
this reduces one remote call.

example code

func main() {
	s := grpc.NewServer(
	)
	srv := service{}
	pb.RegisterExampleServiceServer(s, &srv)

	ctx := context.Background()
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	mux := runtime.NewServeMux()
	err := pb.RegisterExampleServiceHandlerServer(ctx, mux, &srv)
	if err != nil {
		log.Panic(err)
	}

	if err := http.ListenAndServe(serveAddr, mux); err != nil {
		log.Fatalf("http failed to serve: %v", err)
	}
}

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[johanbrandhorst]

Hi @hb-chen! Thanks for your PR. This is an interesting new feature! You'll need to regenerate all the example files with this template change: https://github.com/grpc-ecosystem/grpc-gateway/blob/master/CONTRIBUTING.md#i-want-to-regenerate-the-files-after-making-changes.

[hb-chen]

I signed it!

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[hb-chen]

When I try to support stream, I see the PR(grpc/grpc-go#906 (comment)) of grpc-go, will support for In-Process transport.
So waiting the feature and close this PR.

And now I use buffconn. grpc/grpc-go#1263 (comment)

func main() {
	s := grpc.NewServer(
	)
	srv := service{}
	pb.RegisterExampleServiceServer(s, &srv)

	bcLis := bufconn.Listen(256 * 1024)
	go s.Serve(bcLis)

	ctx := context.Background()
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	mux := runtime.NewServeMux()
	err := pb.RegisterExampleServiceHandlerFromEndpoint(
		ctx,
		mux,
		"",
		[]grpc.DialOption{
			grpc.WithContextDialer(func(ctx context.Context, s string) (net.Conn, error) {
				log.Printf("dial with s:%s", s)
				return bcLis.Dial()
			}),
		},
	)
	if err != nil {
		log.Panic(err)
	}

	if err := http.ListenAndServe(serveAddr, mux); err != nil {
		log.Fatalf("http failed to serve: %v", err)
	}
}

[johanbrandhorst]

@hb-chen The in-process transport is still some time away, and #952 shows there's still interest in this feature. Would you be interested to merge this anyway?

[hb-chen]

@hb-chen The in-process transport is still some time away, and #952 shows there's still interest in this feature. Would you be interested to merge this anyway?

Of course, I will continue this😁

[johanbrandhorst]

Seems like the latest version of the generated files have some compilation errors - I assume this is due to a small problem in the template. Could you take another look please?

[nicklofaso]

+1 for this feature. Much appreciated

[rittneje]

+1
We would be fine even if this new function just didn’t get generated for interfaces using streams. 🙂

[johanbrandhorst]

@hb-chen I'd be happy to merge initial support for just unary requests. What do you think?

[hb-chen]

@hb-chen I'd be happy to merge initial support for just unary requests. What do you think?

I agree with you.
Streaming used less in gateway, and we can wait for gRPC support.

[rittneje]

@hb-chen Any progress on this?

[vipingoel]

+1
Much awaited change.

[hb-chen]

@hb-chen Any progress on this?

Just bazel check failed.
Or you can fork my branch, and build.

[achew22]

@hb-chen, thanks so much for doing this! Looks like I need to push an update to the rules_go stuff to make Bazel work. One moment please. Would you be willing to wait for that PR (I'll mention this one in it) and then rebase off master?

[achew22]

@hb-chen, if you could rebase off of master I think this will pass CI. Thanks so much!

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[johanbrandhorst]

Move this newline before the {{end}} to avoid a newline at the top of non streaming services.

[hb-chen]

On line 579 have streaming condition {{if eq $streaming 1}}.

[johanbrandhorst]

Since we decided not to support streaming endpoints fort now, can we remove this?

[johanbrandhorst]

Let's remove the streaming specific code until it's implemented by gRPC.

[johanbrandhorst]

Since we decided not to support streaming endpoints fort now, can we remove this?

[johanbrandhorst]

Please remove the comments below this line.

[johanbrandhorst]

The new template changes look great, just a quick thought; do you think we could add a test case to the integration tests that calls the unary methods? It shouldn't be too hard, hopefully. Just a sanity test that the new functionality works.

[johanbrandhorst]

@hb-chen I don't want to lose sight of this, would you be able to write the tests or would you like to merge this as is?

[hb-chen]

@hb-chen I don't want to lose sight of this, would you be able to write the tests or would you like to merge this as is?

tks, I will write tests.

[johanbrandhorst]

OK I see we have some tests, I think we can merge this!

[hb-chen]

func Register{{$svc.GetName}}{{$.RegisterFuncSuffix}}Server(ctx context.Context, mux *runtime.ServeMux, server {{$svc.GetName}}Server, opts []grpc.DialOption) error

Oops, the func have an error, opts []grpc.DialOption is unused.
It used for test/bufconn mode, but I forgot to remove it.
remove it and create new pr?

[johanbrandhorst]

Hm, it would be a backward compatibility breaking change at this point... but it's a bit nasty to require something that isn't used. Make a PR and let's merge it quickly 😅.

[achew22]

+1 if we do it quickly I think I'm okay breaking

[rittneje]

@johanbrandhorst It looks like @hb-chen's second PR got merged, so is this issue now officially closed?

[johanbrandhorst]

Did you mean another issue? This is a pull request, and it is merged already.