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一、Hystrix
零碎容错、限流工具
1. 降级
当一个服务调用一个后盾服务调用失败(异样、服务不存在、超时),能够执行以后服务中的一段“降级代码”,来返回降级后果
疾速失败:当调用后盾服务超时,为了不让用户长时间期待,能够间接返回降级后果
1.1 增加降级:
1.1.1 创立 sp07-hystrix 我的项目
1.1.2 增加 hystrix 依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
1.1.3 批改 application.yml
spring:
application:
name: hystrix
server:
port: 3001
#连贯 eureka
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
ribbon:
#单台重试次数
MaxAutoRetries: 1
#更换服务器次数
MaxAutoRetriesNextServer: 2
1.1.4 主程序增加 @EnableCircuitBreaker
启用 hystrix 断路器
启动断路器,断路器提供两个外围性能:
- 降级,超时、出错、不可达到时,对服务降级,返回错误信息或者是缓存数据
- 熔断,当服务压力过大,谬误比例过多时,熔断所有申请,所有申请间接降级
- 能够应用
@SpringCloudApplication
注解代替三个注解
package cn.tedu.sp07;
import org.springframework.boot.SpringApplication;
import org.springframework.cloud.client.SpringCloudApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;
//@EnableCircuitBreaker
//@EnableDiscoveryClient
//@SpringBootApplication
@SpringCloudApplication
public class Sp06RibbonApplication {
@LoadBalanced
@Bean
public RestTemplate getRestTemplate() {SimpleClientHttpRequestFactory f = new SimpleClientHttpRequestFactory();
f.setConnectTimeout(1000);
f.setReadTimeout(1000);
return new RestTemplate(f);
//RestTemplate 中默认的 Factory 实例中,两个超时属性默认是 -1,// 未启用超时,也不会触发重试
//return new RestTemplate();}
public static void main(String[] args) {SpringApplication.run(Sp06RibbonApplication.class, args);
}
}
1.1.5 RibbonController 中增加降级办法
- 为每个办法增加降级办法,例如
getItems()
增加降级办法getItemsFB()
- 增加
@HystrixCommand
注解,指定降级办法名
package com.tedu.sp06.controller;
import cn.tedu.sp01.pojo.Item;
import cn.tedu.sp01.pojo.Order;
import cn.tedu.sp01.pojo.User;
import cn.tedu.web.util.JsonResult;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;
import java.util.List;
@RestController
@Slf4j
public class RibbonController {
@Autowired
private RestTemplate rt;
@GetMapping("/item-service/{orderId}")
@HystrixCommand(fallbackMethod = "getItemsFB")
public JsonResult<List<Item>> getItems(@PathVariable String orderId) {
/* 调用近程的商品服务,取得订单的商品列表
{1} - RestTemplate 本人定义的一种站位符格局
注册核心的注册表:item-service ---- localhost:8001,localhost:8002 从注册表失去 item-service 对应的多个地址,而后在多个地址之间来回调用
*/ return rt.getForObject("http://item-service/{1}", JsonResult.class, orderId); // 用 orderId 填充占位符 {1} }
@PostMapping("/item-service/decreaseNumber")
@HystrixCommand(fallbackMethod = "decreaseNumberFB")
public JsonResult<?> decreaseNumber(@RequestBody List<Item> items) {return rt.postForObject("http://item-service/decreaseNumber", items, JsonResult.class);
}
@GetMapping("/user-service/{userId}")
@HystrixCommand(fallbackMethod = "getUserFB")
public JsonResult<User> getUser(@PathVariable Integer userId) {return rt.getForObject("http://user-service/{1}", JsonResult.class, userId);
}
@GetMapping("/user-service/{userId}/score") // ?score=1000
@HystrixCommand(fallbackMethod = "addScoreFB")
public JsonResult<?> addScore(@PathVariable Integer userId, @RequestParam Integer score) {return rt.getForObject("http://user-service/{1}/score?score={2}", JsonResult.class, userId, score);
}
@GetMapping("/order-service/{orderId}")
@HystrixCommand(fallbackMethod = "getOrderFB")
public JsonResult<Order> getOrder(@PathVariable String orderId) {return rt.getForObject("http://order-service/{1}", JsonResult.class, orderId);
}
@GetMapping("/order-service")
@HystrixCommand(fallbackMethod = "addOrderFB")
public JsonResult<?> addOrder() {return rt.getForObject("http://order-service", JsonResult.class);
}
//////////////////////////////////////////////////////////////
public JsonResult<List<Item>> getItemsFB(String orderId) {return JsonResult.err().msg("获取订单商品列表失败");
}
public JsonResult<?> decreaseNumberFB(List<Item> items) {return JsonResult.err().msg("缩小商品库存失败");
}
public JsonResult<User> getUserFB(Integer userId) {return JsonResult.err().msg("获取用户失败");
}
public JsonResult<?> addScoreFB(Integer userId, @RequestParam Integer score) {return JsonResult.err().msg("减少用户积分失败");
}
public JsonResult<Order> getOrderFB (String orderId){return JsonResult.err().msg("获取订单失败");
}
public JsonResult<?> addOrderFB () {return JsonResult.err().msg("增加订单失败");
}
}
1.2 增加 hystrix 超时设置
hystrix 期待超时后, 会执行降级代码, 疾速向客户端返回降级后果, 默认超时工夫是 1000 毫秒
为了测试 hystrix 降级,咱们把 hystrix 期待超时设置得十分小(500 毫秒)
此设置个别应大于 ribbon 的重试超时时长,例如 10 秒
spring:
application:
name: hystrix
server:
port: 3001
#连贯 eureka
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
ribbon:
#单台重试次数
MaxAutoRetries: 1
#更换服务器次数
MaxAutoRetriesNextServer: 2
#超时设置
hystrix:
command:
default:
execution:
isolation:
thread:
timeoutInMilliseconds: 1000
1.1.6 启动我的项目进行测试
- 通过 hystrix 服务,拜访可能超时失败的 item-service
http://localhost:3001/item-service/35 - 通过 hystrix 服务,拜访未启动的 user-service
http://localhost:3001/user-service/7 - 能够看到,如果 item-service 申请超时,hystrix 会立刻执行降级办法
- 拜访 user-service,因为该服务未启动,hystrix 也会立刻执行降级办法
2. 熔断
服务过热,间接把后盾服务断开,限度服务的申请流量
在特定条件下回主动触发熔断:
- 10 秒 20 次申请(必须首选满足)
- 50% 失败,执行了降级代码
熔断后(断路器关上),所有申请间接执行降级代码,返回降级后果
半开状态:
断路器关上后几秒,会进入半开状态,会向后盾服务尝试发送一次用户申请,如果胜利则敞开断路器,恢复正常。如果失败,持续放弃短路器关上状态几秒。
二、Hystrix Dashboard
Hystrix 仪表盘,故障监控
1. actuator
springboot 提供的我的项目监控信息工具,提供我的项目的各种监控日志数据
- 衰弱状态
- spring 容器中所有的对象
- spring mvc 所有的映射门路
- env 环境变量
- ……
hystrix 利用 actuator 裸露了本人的监控日志,日志端点:hystrix.stream
1.1 pom.xml 增加 actuator 依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
1.2 调整 application.yml 配置,并裸露 hystrix.stream
监控端点
spring:
application:
name: ribbon #hystrix
server:
port: 3001
#连贯 eureka
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
ribbon:
#单台重试次数
MaxAutoRetries: 1
#更换服务器次数
MaxAutoRetriesNextServer: 2
#超时设置
hystrix:
command:
default:
execution:
isolation:
thread:
timeoutInMilliseconds: 1000
management:
endpoints:
web:
exposure:
include: "*"
1.3 拜访 actuator 门路,查看监控端点
2. Hystrix dashboard 仪表盘
2.1 新建 sp08-hystrix-dashboard 我的项目
2.2 批改 pom.xml 文件
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>cn.tedu</groupId>
<artifactId>sp08-hystrix-dashboard</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>sp08-hystrix-dashboard</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Hoxton.RELEASE</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
2.3 批改 application.yml 文件
spring:
application:
name: hystrix-dashboard
server:
port: 4001
#容许从这些服务器抓取日志
hystrix:
dashboard:
proxy-stream-allow-list: localhost
2.4 主程序增加 @EnableHystrixDashboard
注解
package com.tedu.sp08;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
@EnableHystrixDashboard
@SpringBootApplication
public class Sp08HystrixDashboardApplication {public static void main(String[] args) {SpringApplication.run(Sp08HystrixDashboardApplication.class, args);
}
}
2.5 启动,并拜访测试
2.5.1 拜访 hystrix dashboard
- http://localhost:4001/hystrix
2.5.2 填入 hystrix 的监控端点,开启监控
- http://localhost:3001/actuator/hystrix.stream
- 通过 hystrix 拜访服务屡次,察看监控信息
http://localhost:3001/item-service/35
http://localhost:3001/user-service/7
http://localhost:3001/user-service/7/score?score=100
http://localhost:3001/order-service/123abc
http://localhost:3001/order-service/
正文完
发表至: intellij-idea
2020-12-21