feat: support google.api.http in gateway (#2161)

gateway/internal/descriptorsource.go

@@ -2,19 +2,29 @@ package internal
 
 import (
 	"fmt"
+	"net/http"
+	"strings"
 
 	"github.com/fullstorydev/grpcurl"
 	"github.com/jhump/protoreflect/desc"
+	"google.golang.org/genproto/googleapis/api/annotations"
+	"google.golang.org/protobuf/proto"
 )
 
+type Method struct {
+	HttpMethod string
+	HttpPath   string
+	RpcPath    string
+}
+
 // GetMethods returns all methods of the given grpcurl.DescriptorSource.
-func GetMethods(source grpcurl.DescriptorSource) ([]string, error) {
+func GetMethods(source grpcurl.DescriptorSource) ([]Method, error) {
 	svcs, err := source.ListServices()
 	if err != nil {
 		return nil, err
 	}
 
-	var methods []string
+	var methods []Method
 	for _, svc := range svcs {
 		d, err := source.FindSymbol(svc)
 		if err != nil {
@@ -25,10 +35,68 @@ func GetMethods(source grpcurl.DescriptorSource) ([]string, error) {
 		case *desc.ServiceDescriptor:
 			svcMethods := val.GetMethods()
 			for _, method := range svcMethods {
-				methods = append(methods, fmt.Sprintf("%s/%s", svc, method.GetName()))
+				rpcPath := fmt.Sprintf("%s/%s", svc, method.GetName())
+				ext := proto.GetExtension(method.GetMethodOptions(), annotations.E_Http)
+				if ext == nil {
+					methods = append(methods, Method{
+						RpcPath: rpcPath,
+					})
+					continue
+				}
+
+				httpExt, ok := ext.(*annotations.HttpRule)
+				if !ok {
+					methods = append(methods, Method{
+						RpcPath: rpcPath,
+					})
+					continue
+				}
+
+				switch rule := httpExt.GetPattern().(type) {
+				case *annotations.HttpRule_Get:
+					methods = append(methods, Method{
+						HttpMethod: http.MethodGet,
+						HttpPath:   adjustHttpPath(rule.Get),
+						RpcPath:    rpcPath,
+					})
+				case *annotations.HttpRule_Post:
+					methods = append(methods, Method{
+						HttpMethod: http.MethodPost,
+						HttpPath:   adjustHttpPath(rule.Post),
+						RpcPath:    rpcPath,
+					})
+				case *annotations.HttpRule_Put:
+					methods = append(methods, Method{
+						HttpMethod: http.MethodPut,
+						HttpPath:   adjustHttpPath(rule.Put),
+						RpcPath:    rpcPath,
+					})
+				case *annotations.HttpRule_Delete:
+					methods = append(methods, Method{
+						HttpMethod: http.MethodDelete,
+						HttpPath:   adjustHttpPath(rule.Delete),
+						RpcPath:    rpcPath,
+					})
+				case *annotations.HttpRule_Patch:
+					methods = append(methods, Method{
+						HttpMethod: http.MethodPatch,
+						HttpPath:   adjustHttpPath(rule.Patch),
+						RpcPath:    rpcPath,
+					})
+				default:
+					methods = append(methods, Method{
+						RpcPath: rpcPath,
+					})
+				}
 			}
 		}
 	}
 
 	return methods, nil
 }
+
+func adjustHttpPath(path string) string {
+	path = strings.ReplaceAll(path, "{", ":")
+	path = strings.ReplaceAll(path, "}", "")
+	return path
+}

gateway/internal/descriptorsource_test.go

@@ -25,5 +25,9 @@ func TestGetMethods(t *testing.T) {
 	assert.Nil(t, err)
 	methods, err := GetMethods(source)
 	assert.Nil(t, err)
-	assert.EqualValues(t, []string{"hello.Hello/Ping"}, methods)
+	assert.EqualValues(t, []Method{
+		{
+			RpcPath: "hello.Hello/Ping",
+		},
+	}, methods)
 }