今天是2020-12-21。
一。sentinel整合feign
1.pom引入openfeign的starter
2.application.yml:
feign:
sentinel:
enabled:true
3.主启动类：@EnableFeignClients
4.接口PaymentService添加@FeignClients(value=“nacos-payment-provider”,fallback=paymentFallback.class)
5,创建类paymentFallback实现PaymentService，并添加@Component注解
6.创建控制器，注入PaymentService，并调用接口方法完成远程调用
二。sentinel持久化
将配置的规则持久化到nacos保存:
1.pom添加依赖：sentinel-datasource-nacos
2.application.yml:
server:
port: 8401
spring:
application:
name: cloudalibaba-sentinel-service
cloud:
nacos:
discovery:
#nacos地址
server-addr: xxx:8080
sentinel:
transport:
#sentinel监控平台地址
dashboard: xxx:8858
#应用本地会启动一个httpserver与sentinel控制台交互，端口默认8719，如果被占用就+1直到找到未被占用的端口
port: 8719
#如果是docker启动的话，本地服务想看到实时监控要配置这个为本机ip
clientIp: 127.0.0.1
datasource:
ds1:
nacos:
server-addr: xxx:8080
dataId: ${
spring.application.name}
groupId: DEFAULT_GROUP
data-type: json
rule-type: flow
management:
endpoints:
web:
exposure:
include: "*"
3.nacos新建配置文件:cloudalibaba-sentinel-service,格式是json：
[
{
“resource”: “hello”,
“limitApp”: “default”,
“grade”: 1,
“count”: 1,
“strategy”: 0,
“controlBehavior”: 0,
“clusterMode”: false
}
]
点击发布即可，然后重启项目，访问/hello即可看到配置好的流控规则，且生效
4.注：不知道是不是有人和我一样，sentinel是docker装的，不是在本地。可以看到服务在sentinel界面显示了，但是监控不到本地服务的接口调用，配的规则也不生效。这次去nacos搞了持久化配置，sentinel那边也没显示出来，但是我一访问接口，规则居然生效了，搞得人无语凝噎，因为监控不到接口调用之前很多地方只能看着老师做，自己实践不了。不过这种配置文件搞起来也很麻烦，再去实践之前的也没必要了，怎么说呢，这算是把之前最简单的qps流控给实践了，也算是最后赶上了车，一切都是这么的奇妙。
二。分布式事务
分布式微服务，每个服务都会连接自己的数据库。一个请求访问，可能会涉及到多个服务调用，涉及到多个数据源，那么每个服务对自己数据库的操作就需要同步，即都在一个事务里，一个服务对数据库的操作失败，其他服务即使对数据库操作是成功的，也要回滚，这就是分布式事务。
三。docker安装seata1.2
1.docker pull seataio/seata-server:1.2.0
2.docker run -d --name seata-server -e SEATA_IP=xxx -e SEATA_PORT=8091 -p 8091:8091 seataio/seata-server:1.2.0
3.cd /usr/local
4.mkdir -p /usr/local/seata
5.docker cp seata容器id:/seata-server/resources/file.conf /usr/local/seata/file.conf #拷贝容器内文件file.conf到容器外的/usr/local/seata径下
6.docker cp seata容器id:/seata-server/resources/registry.conf /usr/local/seata/registry.conf
7.vim file.conf,修改连接模式为db，并修改数据库连接信息：
store {
## store mode: file、db
mode = "db"
## file store property
file {
## store location dir
dir = "sessionStore"
# branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
maxBranchSessionSize = 16384
# globe session size , if exceeded throws exceptions
maxGlobalSessionSize = 512
# file buffer size , if exceeded allocate new buffer
fileWriteBufferCacheSize = 16384
# when recover batch read size
sessionReloadReadSize = 100
# async, sync
flushDiskMode = async
}
## database store property
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
datasource = "druid"
## mysql/oracle/postgresql/h2/oceanbase etc.
dbType = "mysql"
driverClassName = "com.mysql.cj.jdbc.Driver" #注意这里是mysql8的配置
url = "jdbc:mysql://192.168.100.132:3306/seata?serverTimezone=UTC"
user = "root"
password = "123456"
minConn = 5
maxConn = 30
globalTable = "global_table"
branchTable = "branch_table"
lockTable = "lock_table"
queryLimit = 100
maxWait = 5000
}
}
8.vim registry.conf,将seata 注册进nacos中：
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
type = "nacos"
nacos {
application = "seata-server"
serverAddr = "xxx"
namespace = ""
cluster = "default"
username = ""
password = ""
}
eureka {
serviceUrl = "http://localhost:8761/eureka"
application = "default"
weight = "1"
}
redis {
serverAddr = "localhost:6379"
db = 0
password = ""
cluster = "default"
timeout = 0
}
zk {
cluster = "default"
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
}
consul {
cluster = "default"
serverAddr = "127.0.0.1:8500"
}
etcd3 {
cluster = "default"
serverAddr = "http://localhost:2379"
}
sofa {
serverAddr = "127.0.0.1:9603"
application = "default"
region = "DEFAULT_ZONE"
datacenter = "DefaultDataCenter"
cluster = "default"
group = "SEATA_GROUP"
addressWaitTime = "3000"
}
file {
name = "file.conf"
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3
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"
}
}
9.docker cp file.conf seata容器id:/seata-server/resources/file.conf
10.docker cp registry.conf seata容器id:/seata-server/resources/registry.conf
11.在file.conf指定的连接中创建数据库seata，并执行sql脚本，不然seata启动会失败，
官方要求的seata数据库的脚本
12.docker restart seata容器id
13.docker logs seata容器id，确保启动成功
14.登录nacos查看服务列表，看到seata-server表示配置成功
四。seata
seata是alibaba的开源分布式事务解决方案
重要概念：
1.Transaction ID XID:全局唯一的事务ID
2.Transaction Manager TM：事务管理器，定义全局事务的范围-负责开始一个全局事务、提交或回滚全局事务
3.Transaction Coordinator TC：事务协调者，维护全局或分支事务的状态，驱动全局事务提交或回滚
4.Resource Manager RM：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。
五。seata的处理流程
1.TM向TC申请开启一个全局事务，并生成全局唯一的XID
2.XID在微服务调用的链路上传播
3.RM向TC注册分支事务，将其纳入XID对应全局事务的管辖。
4.TM向TC发起针对XID的全局事务的提交或回滚申请
6.TC调度XID下管辖的全部分支事务完成提交或回滚申请。