Spring Cloud学习--Spring Cloud Consul服务注册与发现

之前我们已经在几篇博客中介绍了以Eureka为注册中心服务注册与发现机制，接下来我们学习了解一下以Consul为注册中心的服务注册与发现。

Consul简介

 Consul 是 HashiCorp 公司推出的开源工具，用于实现分布式系统的服务发现与配置。与其他分布式服务注册与发现的方案，Consul的方案更“一站式”，内置了服务注册与发现框 架、分布一致性协议实现、健康检查、Key/Value存储、多数据中心方案，不再需要依赖其他工具（比如ZooKeeper等）。使用起来也较 为简单。Consul使用Go语言编写，因此具有天然可移植性(支持Linux、windows和Mac OS X)；安装包仅包含一个可执行文件，方便部署，与Docker等轻量级容器可无缝配合 。
1、Consul 下载地址：[https://www.consul.io/downloads.html][https_www.consul.io_downloads.html]
2、执行如下命令启动Consul：consul agent -dev  

3、在浏览器中打开consul提供的管理页面  

Consul 服务提供者

服务提供者将服务信息注册到注册中心consul，在工程的application.yml中需要添加consul相关的地址信息

1、pom.xml引入consul相关jar

<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>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.RELEASE</version>
    </parent>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.tianjunwei</groupId>
    <artifactId>TJWspringCloud-consul</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>TJWspringCloud-consul</name>
    <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>ch.qos.logback</groupId>  
            <artifactId>logback-core</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>ch.qos.logback</groupId>  
            <artifactId>logback-classic</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>ch.qos.logback</groupId>  
            <artifactId>logback-access</artifactId>  
        </dependency>  
    </dependencies>
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/test/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.*</include>
                </includes>
            </resource>
        </resources>
        <plugins>  
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>  
                <groupId>org.apache.maven.plugins</groupId>  
                <artifactId>maven-compiler-plugin</artifactId>  
                <version>2.0.2</version>  
                <configuration>  
                    <source>1.8</source>  
                    <target>1.8</target>  
                </configuration>  
            </plugin>  
        </plugins>  
    </build>
</project>

2、application.yml中添加相关配置

spring:
  cloud:
    consul:
#consul地址
      host: localhost  
#consul 对外提供服务的端口
      port: 8500
      discovery:
#服务提供者对外提供的健康检查接口
        healthCheckPath: /health
        healthCheckInterval: 15s
#服务实例ID
        instance-id: consul-tjw
#应用名称
  application:
    name: consul-tjw
#对外提供服务的端口
server:
  port: 8502

3、添加服务启动代码，并对外提供服务

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@EnableDiscoveryClient
@RestController
public class ConsumerApplication {
    @RequestMapping("/hi")
    public String home() {
        return "hi ,i'm tjw";
    }
    /*
     * 自检
     */
    @RequestMapping("/health")
    public String health() {
        return "health";
    }
    public static void main(String[] args) {
        SpringApplication.run(ConsumerApplication.class, args);
    }
}

4、启动服务提供者之后会在consul的管理页面中看到consul-tjw相关的服务信息

Consul 服务消费者

Consul的服务消费者不需要注册到consul（当然也可以注册到consul中），其只需要在使用服务时通过Consul对外提供的接口获取服务信息即可（应该与Eureka类似）  

1、pom.xml中配置

<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>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.RELEASE</version>
    </parent>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.tianjunwei</groupId>
    <artifactId>TJWspringCloud-consul-client</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>TJWspringCloud-consul-client</name>
    <dependencies>
        <dependency>  
            <groupId>org.springframework.cloud</groupId>  
            <artifactId>spring-cloud-starter-consul-discovery</artifactId>  
        </dependency> 
        <dependency>  
            <groupId>ch.qos.logback</groupId>  
            <artifactId>logback-core</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>ch.qos.logback</groupId>  
            <artifactId>logback-classic</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>ch.qos.logback</groupId>  
            <artifactId>logback-access</artifactId>  
        </dependency>  
    </dependencies>
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/test/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.*</include>
                </includes>
            </resource>
        </resources>
        <plugins>  
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>  
                <groupId>org.apache.maven.plugins</groupId>  
                <artifactId>maven-compiler-plugin</artifactId>  
                <version>2.0.2</version>  
                <configuration>  
                    <source>1.8</source>  
                    <target>1.8</target>  
                </configuration>  
            </plugin>  
        </plugins>  
    </build>
</project>

2、application.properties需要配置consul注册中心的地址，并且配置不需要注册到注册中心即可

server.port=8503
spring.application.name=Consul-Client
spring.cloud.consul.host=127.0.0.1
spring.cloud.consul.port=8500
#设置不需要注册到consul中
spring.cloud.consul.discovery.register=false

3、服务消费者可以根据服务名远程调用服务提供者提供的接口

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;  
@SpringBootApplication  
@EnableDiscoveryClient  
@RestController  
public class ConsulMainClient  {  
    @Autowired
    RestTemplate restTemplate;
    @Autowired(required=true)    
    private LoadBalancerClient loadBalancer;  
    @Autowired(required=true)
    private DiscoveryClient discoveryClient;  
    /** 
     * 从所有服务中选择一个服务（轮询） 
     */  
    @RequestMapping("/discover")  
    public Object discover() {  
        return loadBalancer.choose("consul-tjw").getUri().toString();  
    }  
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
    @RequestMapping(value = "/hi", method = RequestMethod.GET)
    public String add() {
        return restTemplate.getForEntity("http://consul-tjw/hi", String.class).getBody();
    }
    /** 
     * 获取所有服务  
     */  
    @RequestMapping("/services")  
    public Object services() {  
        return discoveryClient.getInstances("consul-tjw");  
    }  
    public static void main( String[] args ) {  
        SpringApplication.run(ConsulMainClient.class, args);  
    }  
}

通过调用http://localhost:8503/hi即可获取到服务提供者提供的数据信息

通过调用http://localhost:8503/services可以看到consul中提供的相关的服务的信息，存储的信息很简单类似Eureka注册中心