start implementing gw serve mux support

pkg/app/app.go

@@ -44,6 +44,9 @@ func (a *App) MustRun() {
 
 	var serverWG sync.WaitGroup
 
+	// TODO: Figure out where to merge GRPC Gateway Serve Mux
+	// into HTTP serve mux
+
 	// Start HTTP (does not block)
 	if a.cfg.HTTPEnabled() {
 		serverWG.Add(1)

pkg/srv/grpc/gateway.go

@@ -0,0 +1,43 @@
+package grpc
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+	"google.golang.org/grpc"
+
+	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/grpc/opts"
+)
+
+const API_PATH = "/api" // TODO: Make Configurable
+
+// TODO: Add GetClientConn method to appGRPCServer that supports TLS, auth, etc..
+// Will probably have to convert server opts to client opts
+func (a *appGRPCServer) registerServiceGatewayHandlers(ctx context.Context, service *opts.GRPCService) {
+	if len(service.GwRegistrationFuncs) < 1 {
+		return
+	} else if a.gatewayMux == nil {
+		a.gatewayMux = runtime.NewServeMux()
+	}
+
+	ctx, span := a.tracer.Start(ctx, "appgrpc.init.prepare.service.gwHandlers", trace.WithAttributes(
+		attribute.String("service", service.Name),
+		attribute.Int("gwHandlers", len(service.GwRegistrationFuncs)),
+	))
+	defer span.End()
+
+	// TODO: move to GetClientConn method which doesn't exist yet
+	clientConn, _ := grpc.NewClient(a.opts.Listen)
+
+	for _, registerGW := range service.GwRegistrationFuncs {
+		registerGW(ctx, a.gatewayMux, clientConn)
+	}
+}
+
+// Add our gateway mux to an existing http.ServeMux
+func (a *appGRPCServer) mergeGatewayMuxWithHTTPMux(mux *http.ServeMux) {
+	mux.Handle(API_PATH, http.StripPrefix(API_PATH, a.gatewayMux))
+}

pkg/srv/grpc/grpc.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"strings"
 
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
 	"github.com/rs/zerolog"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/codes"
@@ -23,10 +24,15 @@ type appGRPCServer struct {
 	serverOpts   []grpc.ServerOption
 	logger       *zerolog.Logger
 	server       *grpc.Server
+	gatewayMux   *runtime.ServeMux
 	shutdownFunc func(context.Context) error
 	doneChan     chan error
 }
 
+func (g *appGRPCServer) GetMux() *runtime.ServeMux {
+	return g.gatewayMux
+}
+
 // Returns a shutdown func, a channel indicating done / error,
 // and an up-front error if server fails to start
 func InitGRPCServer(ctx context.Context, opts *opts.GRPCOpts) (

pkg/srv/grpc/opts/config.go

@@ -0,0 +1,30 @@
+package opts
+
+import (
+	"context"
+
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+	"google.golang.org/grpc"
+
+	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/config"
+)
+
+type GRPCOpts struct {
+	*config.GRPCConfig
+	*AppGRPC
+}
+
+type AppGRPC struct {
+	Services           []*GRPCService
+	UnaryInterceptors  []grpc.UnaryServerInterceptor
+	StreamInterceptors []grpc.StreamServerInterceptor
+	GRPCOpts           []grpc.ServerOption
+	GRPCDone           <-chan error
+}
+
+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
+}

pkg/srv/grpc/opts/grpc_config.go

@@ -1,26 +0,0 @@
-package opts
-
-import (
-	"google.golang.org/grpc"
-
-	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/config"
-)
-
-type GRPCOpts struct {
-	*config.GRPCConfig
-	*AppGRPC
-}
-
-type AppGRPC struct {
-	Services           []*GRPCService
-	UnaryInterceptors  []grpc.UnaryServerInterceptor
-	StreamInterceptors []grpc.StreamServerInterceptor
-	GRPCOpts           []grpc.ServerOption
-	GRPCDone           <-chan error
-}
-
-type GRPCService struct {
-	Name    string            // Descriptive name of service
-	Type    *grpc.ServiceDesc // Type (from protoc generated code)
-	Service any               // Implementation of GRPCService.Type (ptr)
-}

pkg/srv/grpc/prepare.go

@@ -3,7 +3,6 @@ package grpc
 import (
 	"context"
 	"errors"
-	"fmt"
 
 	grpclogging "github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/logging"
 	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
@@ -48,10 +47,7 @@ func (a *appGRPCServer) prepGRPCServer(spanCtx context.Context) error {
 	span.SetAttributes(attribute.Int("grpc.server.serveropts", len(a.serverOpts)))
 
 	// Load given services into server registry
-	for _, service := range a.opts.Services {
-		span.AddEvent(fmt.Sprintf("registered %s service", service.Name))
-		a.server.RegisterService(service.Type, service.Service)
-	}
+	a.registerGRPCServices(ctx)
 	span.SetAttributes(attribute.Int("grpc.server.grpcservices", len(a.opts.Services)))
 
 	// Enable reflection if desired

pkg/srv/grpc/services.go

@@ -0,0 +1,33 @@
+package grpc
+
+import (
+	"context"
+	"fmt"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
+
+	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/grpc/opts"
+)
+
+func (a *appGRPCServer) registerGRPCServices(ctx context.Context) {
+	ctx, span := a.tracer.Start(ctx, "appgrpc.init.prepare.services", trace.WithAttributes(
+		attribute.Int("numServices", len(a.opts.Services)),
+	))
+	defer span.End()
+
+	for _, service := range a.opts.Services {
+		a.registerGRPCService(ctx, service)
+		a.registerServiceGatewayHandlers(ctx, service)
+	}
+
+	span.SetStatus(codes.Ok, "")
+}
+
+func (a *appGRPCServer) registerGRPCService(ctx context.Context, service *opts.GRPCService) {
+	span := trace.SpanFromContext(ctx)
+	span.AddEvent(fmt.Sprintf("registered %s service", service.Name))
+
+	a.server.RegisterService(service.Type, service.Service)
+}