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Go 庫存扣減的幾種實現(xiàn)方法
這里使用了 grpc、proto、gorm、zap、go-redis、go-redsync 等 package
Go Mutex 實現(xiàn)
var m sync.Mutexfunc (*InventoryServer) LockSell(ctx context.Context, req *proto.SellInfo) (*emptypb.Empty, error) { tx := global.DB.Begin() m.Lock() for _, good := range req.GoodsInfo { var i model.Inventory if result := global.DB.Where(&model.Inventory{Goods: good.GoodsId}).First(&i); result.RowsAffected == 0 { tx.Rollback() // 回滾 return nil, status.Errorf(codes.InvalidArgument, "未找到此商品的庫存信息。") } if i.Stocks < good.Num { tx.Rollback() return nil, status.Errorf(codes.ResourceExhausted, "此商品的庫存不足") } i.Stocks -= good.Num tx.Save(&i) } tx.Commit() m.Unlock() return &emptypb.Empty{}, nil}
MySQL 悲觀鎖實現(xiàn)
func (*InventoryServer) ForUpdateSell(ctx context.Context, req *proto.SellInfo) (*emptypb.Empty, error) { tx := global.DB.Begin() for _, good := range req.GoodsInfo { var i model.Inventory if result := tx.Clauses(clause.Locking{ Strength: "UPDATE", }).Where(&model.Inventory{Goods: good.GoodsId}).First(&i); result.RowsAffected == 0 { tx.Rollback() return nil, status.Errorf(codes.InvalidArgument, "未找到此商品的庫存信息。") } if i.Stocks < good.Num { tx.Rollback() return nil, status.Errorf(codes.ResourceExhausted, "此商品的庫存不足") } i.Stocks -= good.Num tx.Save(&i) } tx.Commit() return &emptypb.Empty{}, nil}
MySQL 樂觀鎖實現(xiàn)
func (*InventoryServer) VersionSell(ctx context.Context, req *proto.SellInfo) (*emptypb.Empty, error) { tx := global.DB.Begin() for _, good := range req.GoodsInfo { var i model.Inventory for { // 并發(fā)請求相同條件比較多，防止放棄掉一些請求 if result := global.DB.Where(&model.Inventory{Goods: good.GoodsId}).First(&i); result.RowsAffected == 0 { tx.Rollback() return nil, status.Errorf(codes.InvalidArgument, "未找到此商品的庫存信息.") } if i.Stocks < good.Num { tx.Rollback() // 回滾 return nil, status.Errorf(codes.ResourceExhausted, "此商品的庫存不足") } i.Stocks -= good.Num version := i.Version + 1 if result := tx.Model(&model.Inventory{}). Select("Stocks", "Version"). Where("goods = ? and version= ?", good.GoodsId, i.Version). Updates(model.Inventory{Stocks: i.Stocks, Version: version}); result.RowsAffected == 0 { zap.S().Info("庫存扣減失敗!") } else { break } } } tx.Commit() // 提交 return &emptypb.Empty{}, nil}
Redis 分布式鎖實現(xiàn)
func (*InventoryServer) RedisSell(ctx context.Context, req *proto.SellInfo) (*emptypb.Empty, error) { // redis 分布式鎖 pool := goredis.NewPool(global.Redis) rs := redsync.New(pool) tx := global.DB.Begin() for _, good := range req.GoodsInfo { mutex := rs.NewMutex(fmt.Sprintf("goods_%d", good.GoodsId)) if err := mutex.Lock(); err != nil { return nil, status.Errorf(codes.Internal, "redis:分布式鎖獲取異常") } var i model.Inventory if result := global.DB.Where(&model.Inventory{Goods: good.GoodsId}).First(&i); result.RowsAffected == 0 { tx.Rollback() return nil, status.Errorf(codes.InvalidArgument, "未找到此商品的庫存信息") } if i.Stocks < good.Num { tx.Rollback() return nil, status.Errorf(codes.ResourceExhausted, "此商品的庫存不足") } i.Stocks -= good.Num tx.Save(&i) if ok, err := mutex.Unlock(); !ok || err != nil { return nil, status.Errorf(codes.Internal, "redis:分布式鎖釋放異常") } } tx.Commit() return &emptypb.Empty{}, nil}
測試
涉及到服務(wù)、數(shù)據(jù)庫等環(huán)境，此測試為偽代碼
func main() { var w sync.WaitGroup w.Add(20) for i := 0; i < 20; i++ { go TestForUpdateSell(&w) // 模擬并發(fā)請求 } w.Wait()}func TestForUpdateSell(wg *sync.WaitGroup) { defer wg.Done() _, err := invClient.Sell(context.Background(), &proto.SellInfo{ GoodsInfo: []*proto.GoodsInvInfo{ {GoodsId: 16, Num: 1}, //{GoodsId: 16, Num: 10}, }, }) if err != nil { panic(err) } fmt.Println("庫存扣減成功")}
