一、Seata-Server

1.1 下载

官方下载地址 ：https://seata.io/zh-cn/blog/download.html

1.2 启动

Seata-Server 是开箱即用的，启动 bin 目录下的 seata-server.bat 或者 seata-server.sh 即可

另外可以根据需求添加一些参数，输入 seata-server.sh --help 即可查看参数

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Options:
   --host, -h
     注册到注册中心的ip
   --port, -p
     监听的端口，默认8091
   --storeMode, -m
     日志存储模式：文件、数据库
     默认文件
   --serverNode, -n
     服务节点id，默认通过雪花算法生成
   --seataEnv, -e
     用于多配置隔离的环境名称
   --help

seata-server 的默认启动端口是8091，如果我们要指定18091，只需 seata-server.sh -p 18091 即可

二、Spring Cloud 服务搭建

2.1 pom 依赖

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<dependency>
  <groupId>com.alibaba.cloud</groupId>
  <artifactId>spring-cloud-alibaba-seata</artifactId></dependency>

2.2 配置

2.2.1 registry.conf

在 resources 资源目录下配置 registry.conf 配置文件

示例：

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registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  type = "file"

  nacos {
    application = "seata-server"
    serverAddr = "localhost"
    namespace = ""
    username = ""
    password = ""
  }
  eureka {
    serviceUrl = "http://localhost:8761/eureka"
    weight = "1"
  }
  redis {
    serverAddr = "localhost:6379"
    db = "0"
    password = ""
    timeout = "0"
  }
  zk {
    serverAddr = "127.0.0.1:2181"
    sessionTimeout = 6000
    connectTimeout = 2000
    username = ""
    password = ""
  }
  consul {
    serverAddr = "127.0.0.1:8500"
  }
  etcd3 {
    serverAddr = "http://localhost:2379"
  }
  sofa {
    serverAddr = "127.0.0.1:9603"
    region = "DEFAULT_ZONE"
    datacenter = "DefaultDataCenter"
    group = "SEATA_GROUP"
    addressWaitTime = "3000"
  }
  file {
    name = "file.conf"
  }
}

config {
  # file、nacos 、apollo、zk、consul、etcd3、springCloudConfig
  type = "file"

  nacos {
    serverAddr = "localhost"
    namespace = ""
    group = "SEATA_GROUP"
    username = ""
    password = ""
  }
  consul {
    serverAddr = "127.0.0.1:8500"
  }
  apollo {
    appId = "seata-server"
    apolloMeta = "http://192.168.1.204:8801"
    namespace = "application"
  }
  zk {
    serverAddr = "127.0.0.1:2181"
    sessionTimeout = 6000
    connectTimeout = 2000
    username = ""
    password = ""
  }
  etcd3 {
    serverAddr = "http://localhost:2379"
  }
  file {
    name = "file.conf"
  }
}

该文件指定了 seata 的注册中心和配置中心，如果没有注册中心和配置中心也可指定为文件的形式。最终指定的形式由 registry.type 和 config.type 来决定，如示例中就选择以 file 的形式来作为配置信息

2.2.2 file.conf

以 file 形式做注册和配置时，需在 resources 目录下创建 file.conf（registry.conf 中所配置的文件），如果采用其它的方式则不需要该文件。该文件主要配置 seata 的 ip、端口等信息，示例如下：

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transport {
  # tcp udt unix-domain-socket
  type = "TCP"
  #NIO NATIVE
  server = "NIO"
  #enable heartbeat
  heartbeat = true
  # the client batch send request enable
  enableClientBatchSendRequest = true
  #thread factory for netty
  threadFactory {
    bossThreadPrefix = "NettyBoss"
    workerThreadPrefix = "NettyServerNIOWorker"
    serverExecutorThread-prefix = "NettyServerBizHandler"
    shareBossWorker = false
    clientSelectorThreadPrefix = "NettyClientSelector"
    clientSelectorThreadSize = 1
    clientWorkerThreadPrefix = "NettyClientWorkerThread"
    # netty boss thread size,will not be used for UDT
    bossThreadSize = 1
    #auto default pin or 8
    workerThreadSize = "default"
  }
  shutdown {
    # when destroy server, wait seconds
    wait = 3
  }
  serialization = "seata"
  compressor = "none"
}
service {
  #transaction service group mapping
  vgroup_mapping.my_test_tx_group = "default"
  #only support when registry.type=file, please don't set multiple addresses
  default.grouplist = "localhost:8091"
  #degrade, current not support
  enableDegrade = false
  #disable seata
  disableGlobalTransaction = false
}

client {
  rm {
    asyncCommitBufferLimit = 10000
    lock {
      retryInterval = 10
      retryTimes = 30
      retryPolicyBranchRollbackOnConflict = true
    }
    reportRetryCount = 5
    tableMetaCheckEnable = false
    reportSuccessEnable = false
  }
  tm {
    commitRetryCount = 5
    rollbackRetryCount = 5
  }
  undo {
    dataValidation = true
    logSerialization = "jackson"
    logTable = "undo_log"
  }
  log {
    exceptionRate = 100
  }
}

2.2.3 application.yml

除开数据源等其它配置，最主要的配置如下：

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spring:
  application:
    # 应用名称
    name: storage-gts-seata-example
  cloud:
    alibaba:
      seata:
        # 事务组名称
        tx-service-group: my_test_tx_group

2.2.4 数据源配置

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@Configuration
@ConditionalOnClass(DruidDataSource.class)
@AutoConfigureBefore(DataSourceAutoConfiguration.class)
public class MyDataSourceConfig {
 
    @Primary
    @Bean("dataSource")
    public DataSourceProxy dataSourceProxy(DataSource dataSource) {
        return new DataSourceProxy(dataSource);
    }
}

至此，Spring Cloud 整合 Seata 的基本完成，在事务发起方法上添加 @GlobalTransactional 注解即可

2.3 整合 Feign

分布式事务传播的过程中，需要通过判断事务id xid 来确认同一个事务。

Feign 默认使用线程池隔离，并且在发送请求时会丢弃父线程的请求头，导致 xid 无法正常传播。对此并没有必要改用信号量隔离，只需在过滤器中手动添加请求头即可

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public class SeataXidFilter extends OncePerRequestFilter {
    protected Logger logger = LoggerFactory.getLogger(SeataXidFilter.class);

    public static final String XID_HEADER = "Xid_Header";

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {
        String xid = RootContext.getXID();
        String restXid = request.getHeader(XID_HEADER);
        boolean bind = false;
        if (StringUtils.isBlank(xid) && StringUtils.isNotBlank(restXid)) {
            RootContext.bind(restXid);
            bind = true;
            if (logger.isDebugEnabled()) {
                logger.debug("bind[" + restXid + "] to RootContext");
            }
        }
        try {
            filterChain.doFilter(request, response);
        } finally {
            if (bind) {
                String unbindXid = RootContext.unbind();
                if (logger.isDebugEnabled()) {
                    logger.debug("unbind[" + unbindXid + "] from RootContext");
                }
                if (!restXid.equalsIgnoreCase(unbindXid)) {
                    logger.warn("xid in change during http rest from " + restXid + " to " + unbindXid);
                    if (unbindXid != null) {
                        RootContext.bind(unbindXid);
                        logger.warn("bind [" + unbindXid + "] back to RootContext");
                    }
                }
            }
        }
    }
}

三、数据库脚本

在AT模式下需要创建 undo_log，在上面的 file.conf 中已经做了配置，对此我们需要在数据库中创建 undo_log 回滚日志表。不同数据库的脚本略有差异，以 MySQL 为例：

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CREATE TABLE `undo_log` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `branch_id` bigint(20) NOT NULL,
  `xid` varchar(100) NOT NULL,
  `context` varchar(128) NOT NULL,
  `rollback_info` longblob NOT NULL,
  `log_status` int(11) NOT NULL,
  `log_created` datetime NOT NULL,
  `log_modified` datetime NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

四、示例

官网中已经给了示例，自己做一个 AT 模式 SpringCloud版本的具体实现

仅供参考 无法作为实际业务逻辑