Quick Start
Let's begin with a Microservices example.
Use case
A business logic for user purchasing commodities. The whole business logic is powered by 3 microservices:
- Storage service: deduct storage count on given commodity.
- Order service: create order according to purchase request.
- Account service: debit the balance of user's account.
Architecture
StorageService
public interface StorageService { /** * deduct storage count */ void deduct(String commodityCode, int count); }
OrderService
public interface OrderService { /** * create order */ Order create(String userId, String commodityCode, int orderCount); }
AccountService
public interface AccountService { /** * debit balance of user's account */ void debit(String userId, int money); }
Main business logic
public class BusinessServiceImpl implements BusinessService { private StorageService storageService; private OrderService orderService; /** * purchase */ public void purchase(String userId, String commodityCode, int orderCount) { storageService.deduct(commodityCode, orderCount); orderService.create(userId, commodityCode, orderCount); } }
public class OrderServiceImpl implements OrderService { private OrderDAO orderDAO; private AccountService accountService; public Order create(String userId, String commodityCode, int orderCount) { int orderMoney = calculate(commodityCode, orderCount); accountService.debit(userId, orderMoney); Order order = new Order(); order.userId = userId; order.commodityCode = commodityCode; order.count = orderCount; order.money = orderMoney; // INSERT INTO orders ... return orderDAO.insert(order); }
Distributed Transaction Solution with FESCAR
We just need an annotation @GlobalTransactional
on business method:
@GlobalTransactional public void purchase(String userId, String commodityCode, int orderCount) { ...... }
Example powered by Dubbo + FESCAR
Step 1: Setup database
- Requirement: MySQL with InnoDB engine.
Note: In fact, there should be 3 database for the 3 services in the example use case. However, we can just create one database and configure 3 data sources for simple.
Modify Spring XML with the database URL/username/password you just created.
dubbo-account-service.xml dubbo-order-service.xml dubbo-storage-service.xml
<property name="url" value="jdbc:mysql://x.x.x.x:3306/xxx" /> <property name="username" value="xxx" /> <property name="password" value="xxx" />
Step 2: Create UNDO_LOG table
UNDO_LOG
table is required by FESCAR AT mode.
-- 注意此处0.3.0+ 增加唯一索引 ux_undo_log CREATE TABLE `undo_log` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `branch_id` bigint(20) NOT NULL, `xid` varchar(100) NOT NULL, `rollback_info` longblob NOT NULL, `log_status` int(11) NOT NULL, `log_created` datetime NOT NULL, `log_modified` datetime NOT NULL, `ext` varchar(100) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
Step 3: Create tables for example business
DROP TABLE IF EXISTS `storage_tbl`; CREATE TABLE `storage_tbl` ( `id` int(11) NOT NULL AUTO_INCREMENT, `commodity_code` varchar(255) DEFAULT NULL, `count` int(11) DEFAULT 0, PRIMARY KEY (`id`), UNIQUE KEY (`commodity_code`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS `order_tbl`; CREATE TABLE `order_tbl` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` varchar(255) DEFAULT NULL, `commodity_code` varchar(255) DEFAULT NULL, `count` int(11) DEFAULT 0, `money` int(11) DEFAULT 0, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS `account_tbl`; CREATE TABLE `account_tbl` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` varchar(255) DEFAULT NULL, `money` int(11) DEFAULT 0, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Step 4: Start Server
- Download server package from https://github.com/alibaba/fescar/releases, unzip it.
sh fescar-server.sh $LISTEN_PORT $PATH_FOR_PERSISTENT_DATA e.g. sh fescar-server.sh 8091 /home/admin/fescar/data/
Step 5: Run example
Go to samples repo: Fescar-samples
- Start AccountService
- Start StorageService
- Start OrderService
- Run BusinessService for demo test
TBD: scripts for run demo applications