add cors option

service/command.go

@@ -13,8 +13,8 @@ var cmd = &cobra.Command{
 const (
 	serverAddress = "server_address"
 
-	secure  = "secure"
-	reflect = "reflect"
+	secure     = "secure"
+	reflection = "reflection"
 
 	caCert     = "ca_cert"
 	serverCert = "server_cert"
@@ -31,9 +31,9 @@ func init() {
 	cmd.Flags().Bool(secure, true, "Generate self signed certificate if none provided [$SECURE]")
 	viper.BindPFlag(secure, cmd.Flags().Lookup(secure))
 
-	// reflect
-	cmd.Flags().Bool(reflect, false, "Enable gRPC reflection server [$REFLECT]")
-	viper.BindPFlag(reflect, cmd.Flags().Lookup(reflect))
+	// reflection
+	cmd.Flags().Bool(reflection, false, "Enable gRPC reflection server [$REFLECT]")
+	viper.BindPFlag(reflection, cmd.Flags().Lookup(reflection))
 
 	// ca_cert
 	cmd.Flags().String(caCert, "", "Path to Root CA certificate [$CA_CERT]")
@@ -49,7 +49,7 @@ func init() {
 func parseFlags(o *options) *options {
 	o.address = viper.GetString(serverAddress)
 	o.secure = viper.GetBool(secure)
-	o.reflection = viper.GetBool(reflect)
+	o.reflection = viper.GetBool(reflection)
 	o.caCert = viper.GetString(caCert)
 	o.cert = viper.GetString(serverCert)
 	o.key = viper.GetString(serverKey)

service/options.go

@@ -12,6 +12,7 @@ import (
 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 	"github.com/improbable-eng/grpc-web/go/grpcweb"
 	"github.com/jinzhu/gorm"
+	"github.com/rs/cors"
 	"go.uber.org/multierr"
 	"google.golang.org/grpc"
 
@@ -82,8 +83,8 @@ type Options interface {
 	ClientInterceptors() []grpc.UnaryClientInterceptor
 	StreamClientInterceptors() []grpc.StreamClientInterceptor
 
-	// TODO(adphi): CORS for http handler
 
+	Cors() cors.Options
 	GRPCWeb() bool
 	GRPCWebPrefix() string
 	GRPCWebOpts() []grpcweb.Option
@@ -92,7 +93,7 @@ type Options interface {
 	GatewayPrefix() string
 	GatewayOpts() []runtime.ServeMuxOption
 
-	// TODO(adphi): metrics
+	// TODO(adphi): metrics + tracing
 
 	Default()
 }
@@ -114,6 +115,7 @@ func (o *options) Default() {
 	if o.transport == nil {
 		o.transport = &grpc.Server{}
 	}
+
 }
 
 type Option func(*options)
@@ -258,6 +260,12 @@ func WithSubscriberInterceptor(w ...interface{}) Option {
 	}
 }
 
+func WithCors(opts cors.Options) Option {
+	return func(o *options) {
+		o.cors = opts
+	}
+}
+
 func WithGRPCWeb(b bool) Option {
 	return func(o *options) {
 		o.grpcWeb = b
@@ -329,9 +337,9 @@ type options struct {
 	grpcWeb       bool
 	grpcWebOpts   []grpcweb.Option
 	grpcWebPrefix string
-
 	gateway     RegisterGatewayFunc
 	gatewayOpts []runtime.ServeMuxOption
+	cors          cors.Options
 
 	error         error
 	gatewayPrefix string
@@ -421,6 +429,10 @@ func (o *options) StreamClientInterceptors() []grpc.StreamClientInterceptor {
 	return o.streamClientInterceptors
 }
 
+func (o *options) Cors() cors.Options {
+	return o.cors
+}
+
 func (o *options) GRPCWeb() bool {
 	return o.grpcWeb
 }

service/service.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"reflect"
 	"strings"
 	"sync"
 	"syscall"
@@ -17,12 +18,13 @@ import (
 	"github.com/google/uuid"
 	grpcmiddleware "github.com/grpc-ecosystem/go-grpc-middleware"
 	"github.com/jinzhu/gorm"
+	"github.com/rs/cors"
 	"github.com/sirupsen/logrus"
 	"github.com/soheilhy/cmux"
 	"github.com/spf13/cobra"
 	"go.uber.org/multierr"
 	"google.golang.org/grpc"
-	"google.golang.org/grpc/reflection"
+	greflect "google.golang.org/grpc/reflection"
 
 	"go.linka.cloud/grpc/registry"
 	"go.linka.cloud/grpc/registry/noop"
@@ -116,7 +118,7 @@ func newService(opts ...Option) (*service, error) {
 	}
 	s.server = grpc.NewServer(append(gopts, s.opts.serverOpts...)...)
 	if s.opts.reflection {
-		reflection.Register(s.server)
+		greflect.Register(s.server)
 	}
 	if err := s.gateway(s.opts.gatewayOpts...); err != nil {
 		return nil, err
@@ -180,8 +182,24 @@ func (s *service) run() error {
 
 	errs := make(chan error, 3)
 
+	if reflect.DeepEqual(s.opts.cors, cors.Options{}) {
+		s.opts.cors = cors.Options{
+			AllowedHeaders:   []string{"*"},
+			AllowedMethods:   []string{
+				http.MethodGet,
+				http.MethodPost,
+				http.MethodPut,
+				http.MethodPatch,
+				http.MethodDelete,
+				http.MethodOptions,
+				http.MethodHead,
+			},
+			AllowedOrigins:   []string{"*"},
+			AllowCredentials: true,
+		}
+	}
 	hServer := &http.Server{
-		Handler: s.mux,
+		Handler: cors.New(s.opts.cors).Handler(s.mux),
 	}
 	if s.opts.Gateway() || s.opts.grpcWeb {
 		go func() {