服务注册发现consul之二：在Spring Cloud中使用Consul实现服务的注册和发现

首先安装consul环境，参照之前的文章：《服务注册发现consul之一：consul介绍及安装》中的第一节介绍。

Spring Cloud使用Consul的服务与发现

1、导入依赖pring-cloud-starter-consul-discovery。

2、在其入口文件Application加入注解@EnableDiscoveryClient，开启服务发现（在consul中注册自己）。

3、配置中标明consul信息及自己注册到注册中心的SERVICES和instance-id

spring.cloud.consul.host=localhost
spring.cloud.consul.port=8500
spring.cloud.consul.discovery.healthCheckPath=${management.contextPath}/health
spring.cloud.consul.discovery.healthCheckInterval=15s
spring.cloud.consul.discovery.instance-id=consul-client1
spring.application.name=consul-client1

源码：

spring-cloud-starter-consul-discovery-1.3.3.RELEASE里的pom.xml中引入了spring-cloud-starter-consul，查看spring-cloud-starter-consul-1.3.3.RELEASE.jar中的pom.xml文件中引入了spring-cloud-consul-core和consul-api

再看spring-cloud-consul-core-1.3.3.RELEASE.jar的源代码：

几个配置有：ConsulProperties.java

@ConfigurationProperties("spring.cloud.consul")
@Data
@Validated
public class ConsulProperties {
    /** Consul agent hostname. Defaults to 'localhost'. */
    @NotNull
    private String host = "localhost";

    /** Consul agent port. Defaults to '8500'. */
    @NotNull
    private int port = 8500;

    /** Is spring cloud consul enabled */
    private boolean enabled = true;
}

RetryProperties.java

@ConfigurationProperties("spring.cloud.consul.retry")
@Data
public class RetryProperties {

    /** Initial retry interval in milliseconds. */
    private long initialInterval = 1000;

    /** Multiplier for next interval. */
    private double multiplier = 1.1;

    /** Maximum interval for backoff. */
    private long maxInterval = 2000;

    /** Maximum number of attempts. */
    private int maxAttempts = 6;
}

为了演示consul的注册与发现，下面会创建2个服务和1个client端：

一：服务端1：

1、pom.xml

<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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dxz</groupId>
    <artifactId>cloud-server1</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>cloud-client</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <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-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Dalston.RELEASE</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>

server的启动类：ConsulApp.java

package com.dxz.cloud_server;

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 ConsulApp {  

    @RequestMapping("/home")
    public Object home() {
        System.out.println("cloud-server1");
        return "cloud-server1";
    }  

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

配置文件application.properties

spring.cloud.consul.host=localhost
spring.cloud.consul.port=8500
spring.cloud.consul.discovery.healthCheckPath=${management.contextPath}/health
spring.cloud.consul.discovery.healthCheckInterval=15s
spring.cloud.consul.discovery.instance-id=consul-server1
spring.application.name=consul-server
server.port=8503

由于我们增加了@EnableDiscoveryClient注解，所以，系统启动的时候，就会向consul注册一个服务，服务的名字为consul-server, ID为consul-server1

启动后，访问：http://localhost:8500/ui/#/dc1/services/consul-server，输出如下页面：

访问consul的HTTP API：http://localhost:8500/v1/catalog/service/consul-server 输出如下：

[
    {
        "ID": "ae2b2853-18fa-7042-a157-25da30fcc744",
        "Node": "DESKTOP-PPSFCNC",
        "Address": "127.0.0.1",
        "Datacenter": "dc1",
        "TaggedAddresses": {
            "lan": "127.0.0.1",
            "wan": "127.0.0.1"
        },
        "NodeMeta": {},
        "ServiceID": "consul-server1",
        "ServiceName": "consul-server",
        "ServiceTags": [],
        "ServiceAddress": "DESKTOP-PPSFCNC",
        "ServicePort": 8503,
        "ServiceEnableTagOverride": false,
        "CreateIndex": 316,
        "ModifyIndex": 719
    },
    {
        "ID": "ae2b2853-18fa-7042-a157-25da30fcc744",
        "Node": "DESKTOP-PPSFCNC",
        "Address": "127.0.0.1",
        "Datacenter": "dc1",
        "TaggedAddresses": {
            "lan": "127.0.0.1",
            "wan": "127.0.0.1"
        },
        "NodeMeta": {},
        "ServiceID": "consul-server2",
        "ServiceName": "consul-server",
        "ServiceTags": [],
        "ServiceAddress": "DESKTOP-PPSFCNC",
        "ServicePort": 8504,
        "ServiceEnableTagOverride": false,
        "CreateIndex": 585,
        "ModifyIndex": 721
    }
]

二：服务端2

1、pom.xml同上

2、启动类：

package com.dxz.cloud_server;

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 ConsulApp {  

    @RequestMapping("/home")
    public Object home() {
        System.out.println("cloud-server2");
        return "cloud-server2";
    }  

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

application.properties 配置内容：（端口、instance-id不同）

spring.cloud.consul.host=localhost
spring.cloud.consul.port=8500
spring.cloud.consul.discovery.healthCheckPath=${management.contextPath}/health
spring.cloud.consul.discovery.healthCheckInterval=15s
spring.cloud.consul.discovery.instance-id=consul-server2
spring.application.name=consul-server
server.port=8504

启动后：

三：客户端

项目依赖，只需要spring-cloud-starter-consul-discovery（我的pom同上）

application.properties 配置内容：

spring.cloud.consul.host=localhost
spring.cloud.consul.port=8500
spring.cloud.consul.discovery.healthCheckPath=${management.contextPath}/health
spring.cloud.consul.discovery.healthCheckInterval=15s
spring.cloud.consul.discovery.instance-id=consul-client1
spring.application.name=consul-client1
server.port=8501

主类：

package com.dxz.cloud_client;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
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 ConsulClientApplication {

    @RequestMapping("/home")
    public String home() {
        return "hi ,i'm consul client";
    }

    public static void main(String[] args) {
        new SpringApplicationBuilder(ConsulClientApplication.class).web(true).run(args);
    }
}

主类：ConsulClientApplication.java

package com.dxz.cloud_client;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@EnableDiscoveryClient
@RestController
public class ConsulClientApplication {

    @RequestMapping("/home")
    public String home() {
        return "hi ,i'm consul client";
    }

    @Autowired
    private LoadBalancerClient loadBalancer;  

    @Autowired
    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-server").getUri().toString();
    }  

    /**
     * 获取所有服务
     */
    @RequestMapping("/services")
    public Object services() {
        return discoveryClient.getInstances("consul-server");
    }  

    public static void main(String[] args) {
        new SpringApplicationBuilder(ConsulClientApplication.class).web(true).run(args);
    }
}

启动之后,观看consul如下：

访问http://localhost:8501/services返回如下：

[{"serviceId":"consul-server","host":"DESKTOP-PPSFCNC","port":8503,"secure":false,"metadata":{},"uri":"http://DESKTOP-PPSFCNC:8503"},{"serviceId":"consul-server","host":"DESKTOP-PPSFCNC","port":8504,"secure":false,"metadata":{},"uri":"http://DESKTOP-PPSFCNC:8504"}]

访问：http://localhost:8501/discover

Spring Cloud Consul 配置

核心参数

配置项	默认值
spring.cloud.consul.enabled	true
spring.cloud.consul.host	localhost
spring.cloud.consul.port	8500

服务发现参数

配置项	默认值
spring.cloud.consul.discovery.acl-token
spring.cloud.consul.discovery.catalog-services-watch-delay	10
spring.cloud.consul.discovery.catalog-services-watch-timeout	2
spring.cloud.consul.discovery.datacenters
spring.cloud.consul.discovery.default-query-tag
spring.cloud.consul.discovery.default-zone-metadata-name	zone
spring.cloud.consul.discovery.deregister	true
spring.cloud.consul.discovery.enabled	true
spring.cloud.consul.discovery.fail-fast	true
spring.cloud.consul.discovery.health-check-critical-timeout
spring.cloud.consul.discovery.health-check-interval	10s
spring.cloud.consul.discovery.health-check-path	/actuator/health
spring.cloud.consul.discovery.health-check-timeout
spring.cloud.consul.discovery.health-check-tls-skip-verify
spring.cloud.consul.discovery.health-check-url
spring.cloud.consul.discovery.heartbeat.enabled	false
spring.cloud.consul.discovery.heartbeat.interval-ratio
spring.cloud.consul.discovery.heartbeat.ttl-unit	s
spring.cloud.consul.discovery.heartbeat.ttl-value	30
spring.cloud.consul.discovery.hostname
spring.cloud.consul.discovery.instance-group
spring.cloud.consul.discovery.instance-id	默认为服务名+环境+端口号
spring.cloud.consul.discovery.instance-zone
spring.cloud.consul.discovery.ip-address
spring.cloud.consul.discovery.lifecycle.enabled	true
spring.cloud.consul.discovery.management-port
spring.cloud.consul.discovery.management-suffix	management
spring.cloud.consul.discovery.management-tags
spring.cloud.consul.discovery.port
spring.cloud.consul.discovery.prefer-agent-address	false
spring.cloud.consul.discovery.prefer-ip-address	false
spring.cloud.consul.discovery.query-passing	false
spring.cloud.consul.discovery.register	true
spring.cloud.consul.discovery.register-health-check	true
spring.cloud.consul.discovery.scheme	http
spring.cloud.consul.discovery.server-list-query-tags
spring.cloud.consul.discovery.service-name
spring.cloud.consul.discovery.tags

配置服务参数

配置项	默认值
spring.cloud.consul.config.enabled	true
spring.cloud.consul.config.prefix	config
spring.cloud.consul.config.default-context	application
spring.cloud.consul.config.profile-separator	,
spring.cloud.consul.config.data-key	data
spring.cloud.consul.config.format	KEY_VALUE, PROPERTIES, YAML, FILES
spring.cloud.consul.config.name	${spring.application.name}
spring.cloud.consul.config.acl-token
spring.cloud.consul.config.fail-fast	false
spring.cloud.consul.config.watch.enabled	true
spring.cloud.consul.config.watch.wait-time	55
spring.cloud.consul.config.watch.delay	1000