feat: Implement pagination in GetUsers()

Author: sang-w0o

handler/rpc.go

@@ -56,7 +56,7 @@ func (handler *Handler) GetUser(_ context.Context, request *api.GetUserRequest)
 }
 
 func (handler *Handler) GetUsers(_ context.Context, request *api.GetUsersRequest) (*api.GetUsersResponse, error) {
-	users, err := handler.UserService.GetUsersByNickname(request.Nickname)
+	users, err := handler.UserService.GetUsersByNickname(request.Nickname, request.Page, request.Size, request.Sort)
 	if err != nil {
 		return nil, err
 	}

proto/user.pb.go

@@ -55,6 +55,9 @@ message GetUserResponse {
 
 message GetUsersRequest {
   string nickname = 1;
+  int64 page = 2;
+  int64 size = 3;
+  string sort = 4;
 }
 
 message GetUsersResponse {

proto/user.proto

@@ -21,19 +21,13 @@ func NewGRPCServer(h *handler.Handler) (*GRPCServer, error) {
 	server := grpc.NewServer(
 		grpc.KeepaliveParams(
 			keepalive.ServerParameters{
-				MaxConnectionIdle:     15 * time.Second,
-				MaxConnectionAge:      30 * time.Second,
-				MaxConnectionAgeGrace: 15 * time.Second,
+				MaxConnectionIdle:     10 * time.Second,
+				MaxConnectionAge:      20 * time.Second,
+				MaxConnectionAgeGrace: 10 * time.Second,
 				Time:                  15 * time.Second,
 				Timeout:               10 * time.Second,
 			},
 		),
-		grpc.KeepaliveEnforcementPolicy(
-			keepalive.EnforcementPolicy{
-				MinTime:             3 * time.Second,
-				PermitWithoutStream: true,
-			},
-		),
 		grpcmiddleware.WithUnaryServerChain(
 			grpcrecovery.UnaryServerInterceptor(
 				grpcrecovery.WithRecoveryHandler(handleRecoveryGRPC),

server/grpc-server.go

@@ -55,12 +55,15 @@ func (service *Service) GetUserByID(userId string) (*model.User, error) {
 	return user, nil
 }
 
-func (service *Service) GetUsersByNickname(name string) ([]*model.User, error) {
+func (service *Service) GetUsersByNickname(name string, page int64, size int64, sort string) ([]*model.User, error) {
 	if strings.Trim(name, " ") == "" {
 		return nil, errors.New("empty name")
 	}
-	users, err := service.DB.GetUsersByNickname(name)
+	users, err := service.DB.GetUsersByNickname(name, sort, page, size)
 	if err != nil {
+		if errors.Is(err, userdb.ErrWrongSortValue) {
+			return nil, status.Errorf(codes.InvalidArgument, "invalid sort value %s", sort)
+		}
 		return nil, status.Errorf(codes.Internal, "Error occurred in while processing GetUsers(), %v", err)
 	}
 	return users, nil

service/service.go

@@ -84,10 +84,42 @@ func (db *DB) GetUserByID(userId string) (*model.User, error) {
 	return &user, nil
 }
 
-func (db *DB) GetUsersByNickname(nickname string) ([]*model.User, error) {
+func (db *DB) GetUsersByNickname(nickname string, sort string, page int64, size int64) ([]*model.User, error) {
 	var users []*model.User
-	if err := db.User.Get("nickname", nickname).Index("nickname_idx").All(&users); err != nil {
+
+	dynamoDBSort, err := db.dynamoDBSort(sort)
+	if err != nil {
 		return nil, err
 	}
+
+	query := db.User.Get("nickname", nickname).Index(NicknameIndex.String()).Order(dynamoDBSort)
+	var lastKey dynamo.PagingKey
+
+	for i := int64(0); i <= page; i++ {
+		if i != 0 {
+			users = nil
+		}
+		lastKey, err = query.StartFrom(lastKey).Limit(size).AllWithLastEvaluatedKey(&users)
+		if err != nil {
+			return nil, err
+		}
+		if lastKey == nil {
+			if i < page {
+				users = nil
+			}
+			break
+		}
+	}
 	return users, nil
 }
+
+func (db *DB) dynamoDBSort(sort string) (dynamo.Order, error) {
+	switch sort {
+	case "asc":
+		return dynamo.Ascending, nil
+	case "desc":
+		return dynamo.Descending, nil
+	default:
+		return dynamo.Ascending, ErrWrongSortValue
+	}
+}

userdb/db.go

@@ -0,0 +1,7 @@
+package userdb
+
+import "github.com/pkg/errors"
+
+var (
+	ErrWrongSortValue = errors.New("wrong sort value")
+)

userdb/error.go

@@ -0,0 +1,11 @@
+package userdb
+
+type Index string
+
+const (
+	NicknameIndex Index = "nickname_idx"
+)
+
+func (index Index) String() string {
+	return string(index)
+}