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/app/run.go

@@ -9,9 +9,6 @@ import (
 	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/config"
 )
 
-// TODO: Make Configurable
-const GRPC_GW_API_PATH = "/api"
-
 func (a *App) Done() <-chan any {
 	return a.appDone
 }

pkg/app/run_grpc.go

@@ -25,7 +25,7 @@ func (a *App) runGRPC(ctx context.Context) {
 		}
 
 		a.HTTP.Handlers = append(a.HTTP.Handlers, opts.HTTPHandler{
-			Prefix:      GRPC_GW_API_PATH,
+			Prefix:      a.cfg.GRPC.GRPCGatewayPath,
 			StripPrefix: true,
 			Handler:     a.GRPC.GetGatewayMux(),
 		})

pkg/config/types_grpc.go

@@ -15,4 +15,6 @@ type GRPCConfig struct {
 	LogRequests           bool   `yaml:"logRequests" env:"APP_GRPC_LOG_REQUESTS" json:"logRequests,omitempty"`
 	EnableReflection      bool   `yaml:"enableReflection" env:"APP_GRPC_ENABLE_REFLECTION" json:"enableReflection,omitempty"`
 	EnableInstrumentation bool   `yaml:"enableInstrumentation" env:"APP_GRPC_ENABLE_INSTRUMENTATION" json:"enableInstrumentation,omitempty"` // requires OTEL
+	EnableGRPCGateway     bool   `yaml:"enableGRPCGateway" json:"enableGRPCGateway,omitempty" env:"APP_GRPC_ENABLE_GATEWAY" default:"true"`
+	GRPCGatewayPath       string `yaml:"grpcGatewayPath" json:"grpcGatewayPath,omitempty" env:"APP_GRPC_GATEWAY_PATH" default:"/grpc-api"`
 }

pkg/srv/grpc/gateway.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"net"
 
-	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/trace"
@@ -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/grpc.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"strings"
 
-	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 	"github.com/rs/zerolog"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/codes"

pkg/srv/grpc/opts/config.go

@@ -3,7 +3,7 @@ package opts
 import (
 	"context"
 
-	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 	"google.golang.org/grpc"
 
 	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/config"
@@ -19,18 +19,21 @@ type AppGRPC struct {
 	UnaryInterceptors  []grpc.UnaryServerInterceptor
 	StreamInterceptors []grpc.StreamServerInterceptor
 	GRPCOpts           []grpc.ServerOption
-	GRPCDialOpts       []grpc.DialOption // Map ServerOptions to DialOpts for GRPC Gateway support
+	GRPCDialOpts       []grpc.DialOption        // Map ServerOptions to DialOpts for GRPC Gateway support
+	GRPCGatewayOpts    []runtime.ServeMuxOption // Configure grpc-gateway ServeMux
 	GRPCDone           <-chan error
 	gatewayMux         *runtime.ServeMux
 }
 
 type GRPCService struct {
-	Name                string                                                             // Descriptive name of service
-	Type                *grpc.ServiceDesc                                                  // Type (from protoc generated code)
-	Service             any                                                                // Implementation of GRPCService.Type (ptr)
-	GwRegistrationFuncs []func(context.Context, *runtime.ServeMux, *grpc.ClientConn) error // Gateway regustration handler funcs
+	Name                string               // Descriptive name of service
+	Type                *grpc.ServiceDesc    // Type (from protoc generated code)
+	Service             any                  // Implementation of GRPCService.Type (ptr)
+	GwRegistrationFuncs []GwRegistrationFunc // Gateway regustration handler funcs
 }
 
+type GwRegistrationFunc func(context.Context, *runtime.ServeMux, *grpc.ClientConn) error
+
 func (a *AppGRPC) SetGatewayMux(mux *runtime.ServeMux) {
 	a.gatewayMux = mux
 }

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/grpc/services.go

@@ -19,7 +19,9 @@ func (a *appGRPCServer) registerGRPCServices(ctx context.Context) {
 
 	for _, service := range a.opts.Services {
 		a.registerGRPCService(ctx, service)
-		a.registerServiceGatewayHandlers(ctx, service)
+		if a.opts.EnableGRPCGateway {
+			a.registerServiceGatewayHandlers(ctx, service)
+		}
 	}
 
 	span.SetStatus(codes.Ok, "")

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)
 		}