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

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We just need an annotation @GlobalTransactional on business method:

    @GlobalTransactional
    public void purchase(String userId, String commodityCode, int orderCount) { ...... }

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

Fescar Quick Start