SpringCloud学习笔记（五）

8.Seata分布式事务

8.1. Seata简介

• Seata是一款开源的分布式事务解决方案，致力于提供高性能和简单易用的分布式事务服务。

8.2. Seata工作组件

• XID：全局事务的唯一标识，在微服务调用链中传递，绑定到服务的事务的上下文。
• TC：事务协调者，就是Seata，维护全局和分支事务的状态，驱动全局事务提交或回滚。（以Seata Server的形式独立部署）
• TM：事务管理器，标注全局@GlobalTransactional启动入口动作的微服务模块，是事务的发起者。定义全局事务的范围：开始全局事务、提交或回滚全局事务。
• RM：资源管理器，是MySQL数据库本身，管理分支事务处理的资源，与TC交谈以注册分支事务和报告分支事务的状态，并驱动分支事务提交或回滚。

8.3. Seata工作流程

1.TM向TC申请开启全局事务，创建成功生成全局唯一的XID。

2.XID在微服务调用链中传播。

3.RM向TC注册分支事务，将其纳入XID对应的全局事务的管辖。

4.TM向TC发起针对XID的全局提交或回滚决议。

5.TC调度XID下管辖的全部分支事务完成提交或回滚请求。

8.4. Seata安装

8.4.1.安装流程

• 下载解压

  • https://github.com/seata/seata/releases

• 创建数据库

  • seata的server端需要创建一个数据库，用于存储事务信息

CREATE DATABASE seata;
USE seata;

• 导入表

  • https://github.com/apache/incubator-seata/blob/2.x/script/server/db/mysql.sql

  • 执行sql脚本

• 修改配置文件

  • 修改application.yml

#  Copyright 1999-2019 Seata.io Group.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#  http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

server:
  port: 7091

spring:
  application:
    name: seata-server

logging:
  config: classpath:logback-spring.xml
  file:
    path: ${
   log.home:${
   user.home}/logs/seata}
  extend:
    logstash-appender:
      destination: 127.0.0.1:4560
    kafka-appender:
      bootstrap-servers: 127.0.0.1:9092
      topic: logback_to_logstash

console:
  user:
    username: seata
    password: seata
seata:
  config:
    # support: nacos, consul, apollo, zk, etcd3
    type: nacos
    nacos:
      server-addr: 127.0.0.1:8848
      namespace: ""
      group: SEATA_GROUP
      username: nacos
      password: nacos
  registry:
    # support: nacos, eureka, redis, zk, consul, etcd3, sofa
    type: nacos
    nacos:
      application: seata-server
      server-addr: 127.0.0.1:8848
      group: SEATA_GROUP
      namespace: ""
      cluster: default
      username: nacos
      password: nacos
  store:
    # support: file 、 db 、 redis 、 raft
    mode: db
    db:
      datasource: druid
      db-type: mysql 
      driver-class-name: com.mysql.dj.jdbc.Driver
      url: jdbc:mysql://localhost:3307/seata?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8&rewriteBatchedStatements=true
      user: root
      password: 123456
      minConn: 10
      maxConn: 100
      global-table: global_table
      branch-table: branch_table
      lock-table: lock_table
      distributed-lock-table: distributed_lock
      query-limit: 1000
      maxWait: 5000
  #  server:
  #    service-port: 8091 #If not configured, the default is '${server.port} + 1000'
  security