support runtime.ServeMux opts for grpc-gateway

TODO.md

@@ -1,5 +1,6 @@
 # TODO
 
+- [ ] Test and troubleshoot GRPC Gateway supprot
 - [ ] Finish implementing GRPC service support
 - [ ] Expand config test case to cover GRPC config
 - [ ] Expand tracing

pkg/srv/grpc/gateway.go

@@ -18,7 +18,7 @@ func (a *appGRPCServer) registerServiceGatewayHandlers(ctx context.Context, serv
 	if len(service.GwRegistrationFuncs) < 1 {
 		return
 	} else if a.gatewayMux == nil {
-		a.gatewayMux = runtime.NewServeMux()
+		a.gatewayMux = runtime.NewServeMux(a.opts.GRPCGatewayOpts...)
 	}
 
 	ctx, span := a.tracer.Start(ctx, "appgrpc.init.prepare.service.gwHandlers", trace.WithAttributes(
@@ -50,6 +50,7 @@ func (a *appGRPCServer) GetClientConn(ctx context.Context) *grpc.ClientConn {
 	if err != nil {
 		span.RecordError(err)
 		span.SetStatus(codes.Error, err.Error())
+		panic(err)
 	}
 
 	return clientConn

pkg/srv/grpc/opts/config.go

@@ -20,6 +20,7 @@ type AppGRPC struct {
 	StreamInterceptors []grpc.StreamServerInterceptor
 	GRPCOpts           []grpc.ServerOption
 	GRPCDialOpts       []grpc.DialOption        // Map ServerOptions to DialOpts for GRPC Gateway support
+	GRPCGatewayOpts    []runtime.ServeMuxOption // Configure grpc-gateway ServeMux
 	GRPCDone           <-chan error
 	gatewayMux         *runtime.ServeMux
 }

pkg/srv/grpc/run.go

@@ -8,7 +8,6 @@ import (
 	semconv "go.opentelemetry.io/otel/semconv/v1.27.0"
 )
 
-// TODO: Implement
 func (a *appGRPCServer) runGRPCServer(spanCtx context.Context) error {
 	_, span := a.tracer.Start(spanCtx, "appgrpc.init.start")
 	defer span.End()

pkg/srv/http/http.go

@@ -7,6 +7,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -60,6 +61,13 @@ func prepHTTPServer(opts *opts.AppHTTP) *http.Server {
 	// Inject extra handlers if given
 	// Used for grpc-gateway runtime.ServeMux handlers
 	for _, h := range opts.Handlers {
+		// prefix must end in / to route sub-paths
+		if !strings.HasSuffix(h.Prefix, "/") {
+			h.Prefix = h.Prefix + "/"
+		}
+
+		// if enabled, the path prefix is stripped before
+		// requests are sent to the handler
 		if h.StripPrefix {
 			h.Handler = http.StripPrefix(h.Prefix, h.Handler)
 		}