Consul服务注册与发现

Consul简介

Consul是一套开源的分布式服务发现和配置管理系统，由HashiCorp公司用Go语言开发。

提供了微服务系统中的服务治理、配置中心、控制总线等功能。这些功能中的每一个都可以根据需要单独使用，也可以一起使用以构建全方位的服务网格，总之Consul提供了一种完整的服务网格解决方案。

它具有很多优点，包括：基于raft协议，比较简洁；支持健康检查，同时支持HTTP和DNS协议；支持跨数据中心的WAN集群；提供图形界面；跨平台。支持Linux、Mac、Windows。

安装运行Consul

官网下载，文件中只有consul.exe文件，在cmd中输入consul agent -dev启动。

在浏览器访问http://localhost:8500打开consul控制界面。

服务提供者

创建cloud-providerconsul-payment8006模块。

pom.xml

<?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>cloud2022</artifactId>
        <groupId>com.qrxqrx.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-providerconsul-payment8006</artifactId>


    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-consul-discovery</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-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

application.yml

server:
  port: 8006
spring:
  application:
    name: consul-provider-payment
  cloud:
    consul:
      host: localhost
      port: 8500
      discovery:
        service-name: ${
    spring.application.name}

PaymentMain8006

package com.qrxqrx.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class PaymentMain8006 {
    

    public static void main(String[] args) {
    
        SpringApplication.run(PaymentMain8006.class,args);
    }

}

PaymentController

package com.qrxqrx.springcloud.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.UUID;

@RestController
public class PaymentController {
    

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

    @GetMapping(value = "/payment/consul")
    public String paymentConsul() {
    
        return "consul: " + serverPort + UUID.randomUUID().toString();
    }

}

启动模块后，查看consul控制界面：

服务消费者

创建cloud-consumerconsul-order80模块。

pom.xml

<?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>cloud2022</artifactId>
        <groupId>com.qrxqrx.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-consumerconsul-order80</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-consul-discovery</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-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

application.yml

server:
  port: 80

spring:
  application:
    name: cloud-consumer-order
  cloud:
    consul:
      host: localhost
      port: 8500
      discovery:
        service-name: ${
    spring.application.name}

OrderConsulMain80

package com.qrxqrx.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class OrderConsulMain80 {
    

    public static void main(String[] args) {
    
        SpringApplication.run(OrderConsulMain80.class,args);
    }

}

OrderController

package com.qrxqrx.springcloud.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;

@RestController
@Slf4j
public class OrderController {
    

    public static final String INVOKE_URL = "http://consul-provider-payment";

    @Resource
    private RestTemplate restTemplate;

    @GetMapping(value = "/consumer/payment/consul")
    public String paymentInfo() {
    
        String result = restTemplate.getForObject(INVOKE_URL + "/payment/consul", String.class);
        return result;

    }

}

consul界面：

三个注册中心异同点

组件名	语言	CAP	服务健康检查	对外暴露接口	spring cloud集成
Eureka	Java	AP	可配支持	HTTP	已集成
Consul	Go	CP	支持	HTTP/DNS	已集成
Zookeeper	Java	CP	支持	客户端	已集成

AP：当网络分区出现后，为了保证可用性，系统B可以返回旧值，保证系统的可用性。

CP：当网络分区出现后，为了保证一致性，就必须拒接请求，否则无法保证一致性。