Initial commit

internal/lms/config/config.go

@@ -0,0 +1,78 @@
+package config
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"strconv"
+
+	"github.com/joho/godotenv"
+)
+
+type Config struct {
+	GRPCPort             int
+	GRPCEnableReflection bool
+	EnableHTTPHandler    bool
+	HTTPPort             int
+	LogLevel             string
+	DBHost               string
+	DBPort               int
+	DBUser               string
+	DBPassword           string
+	DBName               string
+	RedisURI             string
+}
+
+func Load() (*Config, error) {
+	_ = godotenv.Load()
+
+	return &Config{
+		GRPCPort:             mustGetInt("GRPC_PORT", 50051), //nolint:mnd // false-positive
+		GRPCEnableReflection: mustGetBool("GRPC_ENABLE_REFLECTION", false),
+		EnableHTTPHandler:    mustGetBool("HTTP_HANDLER_ENABLE", false),
+		HTTPPort:             mustGetInt("HTTP_PORT", 8080), //nolint:mnd // false-positive
+		LogLevel:             getEnv("LOG_LEVEL", "info"),
+		DBHost:               getEnv("POSTGRES_HOST", "localhost"),
+		DBPort:               mustGetInt("POSTGRES_PORT", 5432), //nolint:mnd // false-positive
+		DBUser:               getEnv("POSTGRES_USERNAME", "postgres"),
+		DBPassword:           getEnv("POSTGRES_PASSWORD", "postgres"),
+		DBName:               getEnv("POSTGRES_DATABASE", "postgres"),
+		RedisURI:             getEnv("REDIS_URI", "redis://localhost:6379"),
+	}, nil
+}
+
+func getEnv(key, def string) string {
+	if val := os.Getenv(key); val != "" {
+		return val
+	}
+	return def
+}
+
+func mustGetInt(key string, def int) int {
+	val := getEnv(key, strconv.Itoa(def))
+	n, err := strconv.Atoi(val)
+	if err != nil {
+		log.Fatalf("invalid int for %s: %v", key, err)
+	}
+	return n
+}
+
+func mustGetBool(key string, def bool) bool {
+	val := getEnv(key, strconv.FormatBool(def))
+	b, err := strconv.ParseBool(val)
+	if err != nil {
+		log.Fatalf("invalid bool for %s: %v", key, err)
+	}
+	return b
+}
+
+func (c Config) BuildPostgresConnStr() string {
+	return fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=disable",
+		c.DBHost, c.DBPort, c.DBUser, c.DBPassword, c.DBName)
+}
+
+func (c Config) BuildPostgresDSN() string {
+	return fmt.Sprintf("postgresql://%s:%s@%s/%s?sslmode=disable",
+		c.DBUser, c.DBPassword, net.JoinHostPort(c.DBHost, strconv.Itoa(c.DBPort)), c.DBName)
+}

internal/lms/domain/id.go

@@ -0,0 +1,9 @@
+package domain
+
+import (
+	"errors"
+)
+
+var (
+	ErrInvalidID = errors.New("invalid uuid")
+)

internal/lms/domain/order.go

@@ -0,0 +1,42 @@
+package domain
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/go-playground/validator/v10"
+	"github.com/google/uuid"
+)
+
+var (
+	ErrOrderAlreadyExist = errors.New("order already exist")
+	ErrOrderNotFound     = errors.New("order not found")
+	ErrInvalidOrderData  = errors.New("invalid order data")
+)
+
+type Order struct {
+	ID       uuid.UUID `db:"id"       json:"id"       validate:"required"`
+	Item     string    `db:"item"     json:"item"     validate:"required"`
+	Quantity int32     `db:"quantity" json:"quantity" validate:"required,gt=0"`
+}
+
+func NewOrder(id uuid.UUID, item string, quantity int32) (*Order, error) {
+	order := &Order{
+		ID:       id,
+		Item:     item,
+		Quantity: quantity,
+	}
+
+	err := order.Validate()
+	if err != nil {
+		return nil, err
+	}
+
+	return order, nil
+}
+
+func (o *Order) Validate() error {
+	validate := validator.New()
+
+	return fmt.Errorf("%w: %w", ErrInvalidOrderData, validate.Struct(o))
+}

internal/lms/handler/grpc/errors.go

@@ -0,0 +1,26 @@
+package handler
+
+import (
+	"errors"
+	"log"
+
+	"datarush/internal/lms/domain"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+func mapError(err error) error {
+	if errors.Is(err, domain.ErrOrderNotFound) {
+		return status.Error(codes.NotFound, err.Error())
+	}
+	if errors.Is(err, domain.ErrOrderAlreadyExist) {
+		return status.Error(codes.AlreadyExists, err.Error())
+	}
+	if errors.Is(err, domain.ErrInvalidOrderData) || errors.Is(err, domain.ErrInvalidID) {
+		return status.Error(codes.InvalidArgument, err.Error())
+	}
+
+	log.Printf("internal server error: %v", err)
+	return status.Error(codes.Internal, "internal server error")
+}

internal/lms/handler/grpc/order.go

@@ -0,0 +1,108 @@
+package handler
+
+import (
+	"context"
+
+	"datarush/internal/lms/domain"
+	"datarush/internal/lms/service"
+	pb "datarush/pkg/api/order"
+
+	"github.com/google/uuid"
+)
+
+type OrderHandler struct {
+	pb.UnimplementedOrderServiceServer
+
+	service *service.OrderService
+}
+
+func NewOrderHandler(service *service.OrderService) *OrderHandler {
+	return &OrderHandler{
+		service: service,
+	}
+}
+
+func mapDomainStructToHandler(order *domain.Order) *pb.Order {
+	return &pb.Order{
+		Id:       order.ID.String(),
+		Item:     order.Item,
+		Quantity: order.Quantity,
+	}
+}
+
+func (h *OrderHandler) CreateOrder(
+	ctx context.Context,
+	req *pb.CreateOrderRequest,
+) (*pb.CreateOrderResponse, error) {
+	order, err := h.service.Create(ctx, req.GetItem(), req.GetQuantity())
+	if err != nil {
+		return nil, mapError(err)
+	}
+
+	return &pb.CreateOrderResponse{Id: order.ID.String()}, nil
+}
+
+func (h *OrderHandler) GetOrder(ctx context.Context, req *pb.GetOrderRequest) (*pb.GetOrderResponse, error) {
+	parsedID, err := uuid.Parse(req.GetId())
+	if err != nil {
+		return nil, domain.ErrInvalidID
+	}
+
+	order, err := h.service.Get(ctx, parsedID)
+	if err != nil {
+		return nil, mapError(err)
+	}
+
+	return &pb.GetOrderResponse{Order: mapDomainStructToHandler(order)}, nil
+}
+
+func (h *OrderHandler) UpdateOrder(
+	ctx context.Context,
+	req *pb.UpdateOrderRequest,
+) (*pb.UpdateOrderResponse, error) {
+	parsedID, err := uuid.Parse(req.GetId())
+	if err != nil {
+		return nil, mapError(domain.ErrInvalidID)
+	}
+
+	order, err := h.service.Update(ctx, parsedID, req.GetItem(), req.GetQuantity())
+	if err != nil {
+		return nil, mapError(err)
+	}
+
+	return &pb.UpdateOrderResponse{Order: mapDomainStructToHandler(order)}, nil
+}
+
+func (h *OrderHandler) DeleteOrder(
+	ctx context.Context,
+	req *pb.DeleteOrderRequest,
+) (*pb.DeleteOrderResponse, error) {
+	parsedID, err := uuid.Parse(req.GetId())
+	if err != nil {
+		return nil, domain.ErrInvalidID
+	}
+
+	err = h.service.Delete(ctx, parsedID)
+	if err != nil {
+		return nil, mapError(err)
+	}
+
+	return &pb.DeleteOrderResponse{Success: true}, nil
+}
+
+func (h *OrderHandler) ListOrders(
+	ctx context.Context,
+	_ *pb.ListOrdersRequest,
+) (*pb.ListOrdersResponse, error) {
+	domainOrders, err := h.service.List(ctx)
+	if err != nil {
+		return nil, mapError(err)
+	}
+
+	orders := make([]*pb.Order, 0, len(domainOrders))
+	for _, o := range domainOrders {
+		orders = append(orders, mapDomainStructToHandler(o))
+	}
+
+	return &pb.ListOrdersResponse{Orders: orders}, nil
+}

internal/lms/handler/http/health.go

@@ -0,0 +1,63 @@
+package http
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"time"
+
+	"github.com/jmoiron/sqlx"
+	"github.com/redis/go-redis/v9"
+)
+
+type HealthHandler struct {
+	DB    *sqlx.DB
+	Redis *redis.Client
+}
+
+func NewHealthHandler(db *sqlx.DB, redisDB *redis.Client) *HealthHandler {
+	return &HealthHandler{
+		DB:    db,
+		Redis: redisDB,
+	}
+}
+
+type HealthResponse struct {
+	Status  string            `json:"status"`
+	Details map[string]string `json:"details"`
+}
+
+func (h *HealthHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	ctx, cancel := context.WithTimeout(r.Context(), 2*time.Second)
+	defer cancel()
+
+	details := map[string]string{}
+
+	if err := h.DB.PingContext(ctx); err != nil {
+		details["postgres"] = "unhealthy: " + err.Error()
+	} else {
+		details["postgres"] = "ok"
+	}
+
+	if err := h.Redis.Ping(ctx).Err(); err != nil {
+		details["redis"] = "unhealthy: " + err.Error()
+	} else {
+		details["redis"] = "ok"
+	}
+
+	status := "ok"
+	for _, v := range details {
+		if v != "ok" {
+			status = "unhealthy"
+			break
+		}
+	}
+
+	resp := HealthResponse{Status: status, Details: details}
+
+	w.Header().Set("Content-Type", "application/json")
+	if status != "ok" {
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}
+	_ = json.NewEncoder(w).Encode(resp)
+}

internal/lms/interceptor/logger.go

@@ -0,0 +1,73 @@
+package interceptor
+
+import (
+	"context"
+	"log"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/status"
+)
+
+type LoggerInterceptor struct{}
+
+func NewLoggerInterceptor() *LoggerInterceptor {
+	return &LoggerInterceptor{}
+}
+
+func (i *LoggerInterceptor) Unary() grpc.UnaryServerInterceptor {
+	return func(
+		ctx context.Context,
+		req any,
+		info *grpc.UnaryServerInfo,
+		handler grpc.UnaryHandler,
+	) (any, error) {
+		start := time.Now()
+
+		log.Printf("gRPC method %s called", info.FullMethod)
+
+		resp, err := handler(ctx, req)
+
+		duration := time.Since(start)
+
+		if err != nil {
+			if st, ok := status.FromError(err); ok {
+				log.Printf("error: %s, code: %s, duration: %v",
+					st.Message(), st.Code(), duration)
+			} else {
+				log.Printf("error: %v, duration: %v", err, duration)
+			}
+		} else {
+			log.Printf("method %s completed in %v", info.FullMethod, duration)
+		}
+
+		return resp, err
+	}
+}
+
+func (i *LoggerInterceptor) Stream() grpc.StreamServerInterceptor {
+	return func(
+		srv any,
+		stream grpc.ServerStream,
+		info *grpc.StreamServerInfo,
+		handler grpc.StreamHandler,
+	) error {
+		start := time.Now()
+
+		log.Printf("gRPC stream method %s started", info.FullMethod)
+
+		err := handler(srv, stream)
+
+		duration := time.Since(start)
+
+		if err != nil {
+			log.Printf("stream method %s failed: %v, duration: %v",
+				info.FullMethod, err, duration)
+		} else {
+			log.Printf("stream method %s completed in %v",
+				info.FullMethod, duration)
+		}
+
+		return err
+	}
+}

internal/lms/repository/inmemory/order.go

@@ -0,0 +1,102 @@
+package inmemory
+
+import (
+	"context"
+	"sync"
+
+	"datarush/internal/lms/domain"
+
+	"github.com/google/uuid"
+)
+
+type OrderRepository struct {
+	mu     sync.RWMutex
+	orders map[string]*domain.Order
+}
+
+func NewOrderRepository() *OrderRepository {
+	return &OrderRepository{
+		orders: make(map[string]*domain.Order),
+	}
+}
+
+func (r *OrderRepository) Create(ctx context.Context, order *domain.Order) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if _, ok := r.orders[order.ID.String()]; ok {
+		return domain.ErrOrderAlreadyExist
+	}
+	r.orders[order.ID.String()] = order
+
+	return nil
+}
+
+func (r *OrderRepository) Get(ctx context.Context, id uuid.UUID) (*domain.Order, error) {
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	order, ok := r.orders[id.String()]
+	if !ok {
+		return nil, domain.ErrOrderNotFound
+	}
+
+	return order, nil
+}
+
+func (r *OrderRepository) Update(ctx context.Context, order *domain.Order) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if _, ok := r.orders[order.ID.String()]; !ok {
+		return domain.ErrOrderNotFound
+	}
+	r.orders[order.ID.String()] = order
+
+	return nil
+}
+
+func (r *OrderRepository) Delete(ctx context.Context, id uuid.UUID) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if _, ok := r.orders[id.String()]; !ok {
+		return domain.ErrOrderNotFound
+	}
+
+	delete(r.orders, id.String())
+
+	return nil
+}
+
+func (r *OrderRepository) List(ctx context.Context) ([]*domain.Order, error) {
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	orders := make([]*domain.Order, 0, len(r.orders))
+	for _, order := range r.orders {
+		orders = append(orders, order)
+	}
+
+	return orders, nil
+}

internal/lms/repository/order.go

@@ -0,0 +1,17 @@
+package repository
+
+import (
+	"context"
+
+	"datarush/internal/lms/domain"
+
+	"github.com/google/uuid"
+)
+
+type OrderRepository interface {
+	Create(ctx context.Context, order *domain.Order) error
+	Get(ctx context.Context, id uuid.UUID) (*domain.Order, error)
+	Update(ctx context.Context, order *domain.Order) error
+	Delete(ctx context.Context, id uuid.UUID) error
+	List(ctx context.Context) ([]*domain.Order, error)
+}

internal/lms/repository/postgres/order.go

@@ -0,0 +1,243 @@
+package postgres
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log"
+	"time"
+
+	"datarush/internal/lms/domain"
+
+	"github.com/google/uuid"
+	"github.com/jmoiron/sqlx"
+	"github.com/redis/go-redis/v9"
+)
+
+const (
+	orderCachePrefix = "order:"
+	cacheTTL         = 5 * time.Minute
+)
+
+type OrderRepository struct {
+	db          *sqlx.DB
+	redisClient *redis.Client
+	cacheEnable bool
+}
+
+type Config struct {
+	CacheEnable bool
+}
+
+func NewOrderRepository(db *sqlx.DB, redisClient *redis.Client, config *Config) *OrderRepository {
+	if config == nil {
+		config = &Config{
+			CacheEnable: true,
+		}
+	}
+
+	return &OrderRepository{
+		db:          db,
+		redisClient: redisClient,
+		cacheEnable: config.CacheEnable,
+	}
+}
+
+func (r *OrderRepository) cacheKey(id string) string {
+	return orderCachePrefix + id
+}
+
+func (r *OrderRepository) Create(ctx context.Context, order *domain.Order) error {
+	tx, err := r.db.BeginTxx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("begin transaction: %w", err)
+	}
+	defer tx.Rollback()
+
+	query := `
+		insert into orders (id, item, quantity)
+		values (:id, :item, :quantity)
+	`
+
+	if _, err := tx.NamedExecContext(ctx, query, order); err != nil {
+		return fmt.Errorf("create order: %w", err)
+	}
+
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("commit transaction: %w", err)
+	}
+
+	if r.cacheEnable {
+		if err := r.setCacheWithRetry(ctx, order); err != nil {
+			log.Printf("warn: cache set error for order %s: %v", order.ID, err)
+		}
+	}
+
+	return nil
+}
+
+func (r *OrderRepository) Get(ctx context.Context, id uuid.UUID) (*domain.Order, error) {
+	if r.cacheEnable {
+		if order, err := r.getFromCache(ctx, id.String()); err == nil {
+			return order, nil
+		} else if !errors.Is(err, redis.Nil) {
+			log.Printf("warn: cache get error for order %s: %v", id, err)
+		}
+	}
+
+	const query = `
+		select id, item, quantity
+		from orders
+		where id = $1
+	`
+
+	var order domain.Order
+	if err := r.db.GetContext(ctx, &order, query, id); err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, domain.ErrOrderNotFound
+		}
+		return nil, fmt.Errorf("get order by id: %w", err)
+	}
+
+	if r.cacheEnable {
+		if err := r.setCacheWithRetry(ctx, &order); err != nil {
+			log.Printf("warn: cache set error for order %s: %v", id, err)
+		}
+	}
+
+	return &order, nil
+}
+
+func (r *OrderRepository) Update(ctx context.Context, order *domain.Order) error {
+	tx, err := r.db.BeginTxx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("begin transaction: %w", err)
+	}
+	defer tx.Rollback()
+
+	query := `
+		update orders 
+		set item = :item, quantity = :quantity
+		where id = :id
+	`
+
+	result, err := tx.NamedExecContext(ctx, query, order)
+	if err != nil {
+		return fmt.Errorf("update order: %w", err)
+	}
+
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("get rows affected: %w", err)
+	}
+
+	if rowsAffected == 0 {
+		return domain.ErrOrderNotFound
+	}
+
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("commit transaction: %w", err)
+	}
+
+	if r.cacheEnable {
+		if err := r.setCacheWithRetry(ctx, order); err != nil {
+			log.Printf("warn: cache set error for order %s: %v", order.ID, err)
+		}
+	}
+
+	return nil
+}
+
+func (r *OrderRepository) Delete(ctx context.Context, id uuid.UUID) error {
+	tx, err := r.db.BeginTxx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("begin transaction: %w", err)
+	}
+	defer tx.Rollback()
+
+	const query = `
+		delete from orders
+		where id = $1
+	`
+
+	result, err := tx.ExecContext(ctx, query, id)
+	if err != nil {
+		return fmt.Errorf("delete order: %w", err)
+	}
+
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("get rows affected: %w", err)
+	}
+
+	if rowsAffected == 0 {
+		return domain.ErrOrderNotFound
+	}
+
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("commit transaction: %w", err)
+	}
+
+	r.invalidateCache(ctx, id.String())
+	return nil
+}
+
+func (r *OrderRepository) List(ctx context.Context) ([]*domain.Order, error) {
+	const query = `
+		select id, item, quantity
+		from orders
+		order by id
+	`
+
+	var orders []*domain.Order
+	if err := r.db.SelectContext(ctx, &orders, query); err != nil {
+		return nil, fmt.Errorf("list orders: %w", err)
+	}
+
+	return orders, nil
+}
+
+func (r *OrderRepository) getFromCache(ctx context.Context, id string) (*domain.Order, error) {
+	data, err := r.redisClient.Get(ctx, r.cacheKey(id)).Bytes()
+	if err != nil {
+		return nil, err
+	}
+
+	var order domain.Order
+	if err := json.Unmarshal(data, &order); err != nil {
+		r.redisClient.Del(ctx, r.cacheKey(id))
+		return nil, err
+	}
+
+	return &order, nil
+}
+
+func (r *OrderRepository) setCacheWithRetry(ctx context.Context, order *domain.Order) error {
+	data, err := json.Marshal(order)
+	if err != nil {
+		return err
+	}
+
+	key := r.cacheKey(order.ID.String())
+
+	err = r.redisClient.Set(ctx, key, data, cacheTTL).Err()
+
+	return err
+}
+
+func (r *OrderRepository) invalidateCache(_ context.Context, id string) {
+	if !r.cacheEnable {
+		return
+	}
+
+	go func() {
+		ctx, cancel := context.WithTimeout(context.Background(), r.redisClient.Options().ReadTimeout)
+		defer cancel()
+
+		if err := r.redisClient.Del(ctx, r.cacheKey(id)).Err(); err != nil {
+			log.Printf("warn: cache invalidation failed for order %s: %v", id, err)
+		}
+	}()
+}

internal/lms/server/server.go

@@ -0,0 +1,177 @@
+package server
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"time"
+
+	"datarush/internal/lms/config"
+	"datarush/internal/lms/interceptor"
+
+	grpcHandlers "datarush/internal/lms/handler/grpc"
+	httpHandlers "datarush/internal/lms/handler/http"
+	orderPostgresRepo "datarush/internal/lms/repository/postgres"
+	"datarush/internal/lms/service"
+
+	pb "datarush/pkg/api/order"
+
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
+	"github.com/jmoiron/sqlx"
+	_ "github.com/lib/pq" // postgres driver
+	"github.com/redis/go-redis/v9"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/reflection"
+)
+
+const (
+	httpReadTimeout      = 10 * time.Second
+	httpWriteTimeout     = 10 * time.Second
+	httpIdleTimeout      = 60 * time.Second
+	redisRetryCount      = 2
+	redisMinRetryBackoff = 50 * time.Millisecond
+	redisMaxRetryBackoff = 200 * time.Millisecond
+	redisDialTimeout     = 1 * time.Second
+	redisDialerRetries   = 3
+	redisTimeout         = 2 * time.Second
+)
+
+type Server struct {
+	grpcServer *grpc.Server
+	config     *config.Config
+	db         *sqlx.DB
+	redisDB    *redis.Client
+}
+
+func New(cfg *config.Config) *Server {
+	loggerInterceptor := interceptor.NewLoggerInterceptor()
+
+	grpcServer := grpc.NewServer(
+		grpc.UnaryInterceptor(loggerInterceptor.Unary()),
+		grpc.StreamInterceptor(loggerInterceptor.Stream()),
+	)
+
+	return &Server{
+		grpcServer: grpcServer,
+		config:     cfg,
+	}
+}
+
+func runHTTPHandler(s *Server, grpcServerEndpoint *string) error {
+	ctx := context.Background()
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	gwmux := runtime.NewServeMux()
+	opts := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials())}
+	err := pb.RegisterOrderServiceHandlerFromEndpoint(ctx, gwmux, *grpcServerEndpoint, opts)
+	if err != nil {
+		return err
+	}
+
+	mux := http.NewServeMux()
+	mux.Handle("/healthz", httpHandlers.NewHealthHandler(s.db, s.redisDB))
+	mux.Handle("/", gwmux)
+
+	srv := &http.Server{
+		Addr:         fmt.Sprintf(":%d", s.config.HTTPPort),
+		Handler:      mux,
+		ReadTimeout:  httpReadTimeout,
+		WriteTimeout: httpWriteTimeout,
+		IdleTimeout:  httpIdleTimeout,
+	}
+
+	return srv.ListenAndServe()
+}
+
+func getDatabase(cfg config.Config) (*sqlx.DB, error) {
+	db, err := sqlx.Connect("postgres", cfg.BuildPostgresConnStr())
+	if err != nil {
+		return nil, fmt.Errorf("connect to database: %w", err)
+	}
+
+	return db, nil
+}
+
+func getRedis(cfg config.Config) (*redis.Client, error) {
+	conn, err := redis.ParseURL(cfg.RedisURI)
+	client := redis.NewClient(&redis.Options{
+		Addr:               conn.Addr,
+		MaxRetries:         redisRetryCount,
+		MinRetryBackoff:    redisMinRetryBackoff,
+		MaxRetryBackoff:    redisMaxRetryBackoff,
+		DialTimeout:        redisDialTimeout,
+		DialerRetries:      redisDialerRetries,
+		DialerRetryTimeout: redisDialTimeout,
+		ReadTimeout:        redisTimeout,
+		WriteTimeout:       redisTimeout,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("parse Redis URI: %w", err)
+	}
+
+	_, err = client.Ping(context.Background()).Result()
+	if err != nil {
+		return nil, fmt.Errorf("connect to Redis server: %w", err)
+	}
+
+	return client, nil
+}
+
+func (s *Server) RegisterServices() {
+	db, err := getDatabase(*s.config)
+	if err != nil {
+		log.Print(err)
+	}
+	s.db = db
+
+	redisDB, err := getRedis(*s.config)
+	if err != nil {
+		log.Print(err)
+	}
+	s.redisDB = redisDB
+
+	orderRepo := orderPostgresRepo.NewOrderRepository(db, redisDB, &orderPostgresRepo.Config{CacheEnable: true})
+	orderService := service.NewOrderService(orderRepo)
+	orderHandler := grpcHandlers.NewOrderHandler(orderService)
+
+	pb.RegisterOrderServiceServer(s.grpcServer, orderHandler)
+
+	if s.config.GRPCEnableReflection {
+		reflection.Register(s.grpcServer)
+		log.Println("gRPC server will start with reflection")
+	}
+}
+
+func (s *Server) Start() error {
+	addr := fmt.Sprintf(":%d", s.config.GRPCPort)
+	lis, err := net.Listen("tcp", addr) //nolint:noctx // no need to use context here
+	if err != nil {
+		return fmt.Errorf("failed to listen: %w", err)
+	}
+
+	if s.config.EnableHTTPHandler {
+		go func() {
+			log.Printf("starting HTTP gateway on port %d", s.config.HTTPPort)
+			if err := runHTTPHandler(s, &addr); err != nil {
+				log.Printf("HTTP gateway failed: %v", err)
+			}
+		}()
+	}
+
+	log.Printf("starting gRPC server on port %d", s.config.GRPCPort)
+
+	if err := s.grpcServer.Serve(lis); err != nil {
+		return fmt.Errorf("failed to serve: %w", err)
+	}
+
+	return nil
+}
+
+func (s *Server) Stop() {
+	s.grpcServer.GracefulStop()
+	log.Println("gRPC server stopped gracefully")
+}

internal/lms/service/order.go

@@ -0,0 +1,56 @@
+package service
+
+import (
+	"context"
+
+	"datarush/internal/lms/domain"
+	"datarush/internal/lms/repository"
+
+	"github.com/google/uuid"
+)
+
+type OrderService struct {
+	repo repository.OrderRepository
+}
+
+func NewOrderService(repo repository.OrderRepository) *OrderService {
+	return &OrderService{
+		repo: repo,
+	}
+}
+
+func (s *OrderService) Create(ctx context.Context, item string, quantity int32) (*domain.Order, error) {
+	order, err := domain.NewOrder(uuid.New(), item, quantity)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := s.repo.Create(ctx, order); err != nil {
+		return nil, err
+	}
+	return order, nil
+}
+
+func (s *OrderService) Get(ctx context.Context, id uuid.UUID) (*domain.Order, error) {
+	return s.repo.Get(ctx, id)
+}
+
+func (s *OrderService) Update(ctx context.Context, id uuid.UUID, item string, quantity int32) (*domain.Order, error) {
+	order, err := domain.NewOrder(id, item, quantity)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := s.repo.Update(ctx, order); err != nil {
+		return nil, err
+	}
+	return order, nil
+}
+
+func (s *OrderService) Delete(ctx context.Context, id uuid.UUID) error {
+	return s.repo.Delete(ctx, id)
+}
+
+func (s *OrderService) List(ctx context.Context) ([]*domain.Order, error) {
+	return s.repo.List(ctx)
+}