《SpringCloud專題16》-Hystrix熔斷器

1.概述

1.1.分布式系統面臨的問題

複雜分布式體系結構中的應用程式 有數10個依賴關系,每個依賴關系在某些時候将不可避免地失敗

1.2.是什麼

1.3.能幹嘛

服務降級
服務熔斷
接近實時的監控      

1.4.官網資料

​​https://github.com/Netflix/hystrix/wiki​​​

1.5.官宣,停更進維

​​https://github.com/Netflix/hystrix​​​

被動修複bugs
不再接受合并請求
不再釋出新版本      

2.HyStrix重要概念

2.1.服務降級

伺服器忙,請稍後再試,不讓用戶端等待并立刻傳回一個友好提示,fallback

2.2.哪些情況會發出降級

程式運作異常
逾時
服務熔斷觸發服務降級
線程池/信号量也會導緻服務降級      

2.3.服務熔斷

類比保險絲達到最大服務通路後,直接拒絕通路,拉閘限電,然後調用服務降級的方法并傳回友好提示

就是保險絲

服務的降級->進而熔斷->恢複調用鍊路      

2.4.服務限流

秒殺高并發等操作,嚴禁一窩蜂的過來擁擠,大家排隊,一秒鐘N個,有序進行

3.hystrix案例

3.1.建構

建立cloud-provider-hystrix-payment8001

POM

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud2020</artifactId>
        <groupId>com.itxiongmao.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-provider-hystrix-payment8001</artifactId>

    <dependencies>
        
        <!--   hystrix     -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>


        <dependency>
            <groupId>com.itxiongmao.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>

    </dependencies>


</project>      

YML

server:
  port: 8001
spring:
  application:
    name: cloud-provider-hystrix-payment
eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka      

主啟動

package com.itxiongmao;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

/**
 * @BelongsProject: springcloud2020
 * @BelongsPackage: com.itxiongmao
 * @CreateTime: 2020-11-22 12:37
 * @Description: TODO
 */
@SpringBootApplication
@EnableEurekaClient
public class PaymentHystrixMain8001 {
    public static void main(String[] args) {
        SpringApplication.run(PaymentHystrixMain8001.class, args);
    }
}      

業務類

service

package com.itxiongmao.service;

/**
 * @BelongsProject: springcloud2020
 * @BelongsPackage: com.itxiongmao.service
 * @CreateTime: 2020-11-22 12:39
 * @Description: TODO
 */
public interface PaymentService {

    String getPaymentInfo_OK(Integer id);
    
   String paymentInfo_TimeOut(Integer id);
}      

package com.itxiongmao.service.impl;

import com.itxiongmao.service.PaymentService;
import org.springframework.stereotype.Service;

import java.util.concurrent.TimeUnit;

/**
 * @BelongsProject: springcloud2020
 * @BelongsPackage: com.itxiongmao.service.impl
 * @CreateTime: 2020-11-22 12:39
 * @Description: TODO
 */
@Service
public class PaymentServiceImpl implements PaymentService {

    /*
     * 正常通路
     * @param id
     * @return
     */
    @Override
    public String getPaymentInfo_OK(Integer id) {
        return "線程池:" + Thread.currentThread().getName() + " paymentInfo_OK,id:" + id + "\t" + "O(∩_∩)O哈哈~";
    }

    /**
     * 逾時通路
     *
     * @param id
     * @return
     */
    @Override
    public String paymentInfo_TimeOut(Integer id) {
        int timeNumber = 3;
        try {
            // 暫停3秒鐘
            TimeUnit.SECONDS.sleep(timeNumber);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "線程池:" + Thread.currentThread().getName() + " paymentInfo_TimeOut,id:" + id + "\t" +
                "O(∩_∩)O哈哈~  耗時(秒)" + timeNumber;
    }
}      

PaymentController

package com.itxiongmao.controller;


import com.itxiongmao.service.PaymentService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.concurrent.TimeUnit;

@RestController
@Slf4j
public class PaymentController {

    @Resource
    private PaymentService paymentService;

    @Value("${server.port}")
    private String servicePort;

    /**
     * 正常通路
     *
     * @param id
     * @return
     */
    @GetMapping("/payment/hystrix/ok/{id}")
    public String paymentInfo_OK(@PathVariable("id") Integer id) {
        String result = paymentService.getPaymentInfo_OK(id);
        log.info("*****result:" + result);
        return result;
    }

    /**
     * 逾時通路
     *
     * @param id
     * @return
     */
    @GetMapping("/payment/hystrix/timeout/{id}")
    public String paymentInfo_TimeOut(@PathVariable("id") Integer id) {
        String result = paymentService.paymentInfo_TimeOut(id);
        log.info("*****result:" + result);
        return result;

    }
}      

3.2.正常測試

啟動eureka7001
啟動eureka-provider-hystrix-payment8001      

通路

success的方法

​​​ http://localhost:8001/payment/hystrix/ok/31​​

每次調用耗費5秒鐘

​​​ http://localhost:8001/payment/hystrix/timeout/31​​