DEMO code for the project: https://github.com/heyu52/-spring-cloud
What is Consul?
Official website: https://www.consul.io/
The following is from: https://www.jianshu.com/p/e0986abbfe48
Consul has several components, but in general, it is a tool for service discovery and configuration in the infrastructure. It provides several key functions:

• Service Discovery
  Consul client can provide services, such as api or mysql, or use Consul client to discover the provider of a specified service. With DNS or HTTP, applications can easily find the services they depend on.

• Health examination
  Consul client can provide any number of health checks, either associated with a given service ("Web server returns 200 OK") or with a local node ("memory utilization is less than 90%"). This information can be used to monitor the performance of the cluster, and the service discovery component uses this information to remove traffic from the problematic host.

• KV Store
  Applications can use Consul's hierarchical key/value storage, including dynamic configuration, function tags, coordination, leader election, and so on. The simple HTTP API makes it easy to use.

• Multiple Data Centers
  Consul supports multiple data centers. This means that Consul users don't have to worry about building additional abstraction layers to extend to multiple regions.

• Secure Inter-Service Communication

Bright spot

• HTTP API
• DNS( xxx.service.consul )
• Linkage with Nginx, such as ngx_http_consul_backend_module

Docker Installation
Address: https://hub.docker.com//consul

docker pull consul

Function

docker run --name consul -d -p 8500:8500 -p 8600:8600/udp consul

Enter the Management Interface
Browser input: http://192.168.0.123:8500/ui/dc1/services

This page is more concise.

Create a project
Create goodspo

pom additions

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

To configure

server.port=0
spring.application.name=GoodsPO
management.endpoint.health.show-details=always

spring.cloud.consul.host=192.168.0.123
spring.cloud.consul.port=8500
spring.cloud.consul.discovery.prefer-ip-address=true

Startup class

package com.csdn.GoodsPO;

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

@EnableDiscoveryClient
@SpringBootApplication
public class GoodsPoApplication {

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

}

At the same time, create goodspr
pom additions

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

To configure

server.port=0
spring.application.name=GoodsPR
management.endpoint.health.show-details=always

spring.cloud.consul.host=192.168.0.123
spring.cloud.consul.port=8500
spring.cloud.consul.discovery.prefer-ip-address=true

Startup class

package com.csdn.GoodsPR;

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

@EnableDiscoveryClient
@SpringBootApplication
public class GoodsPrApplication {

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

}

Start the project and refresh http://192.168.0.123:8500/ui/dc1/services

Here you can see the service registration. I showed an error because I restarted the project. Let's try GoodsPO

As you can see here, the system has allocated 13464 port number by default. Let's click GoodsPO-0 again.

Here I want to explain that I set the version to 2.1.4.RELEASE,2.1.8 health check is a problem.

Modify goodspo startup class

package com.csdn.GoodsPO;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@EnableDiscoveryClient
@SpringBootApplication
public class GoodsPoApplication {

    @LoadBalanced
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
    public static void main(String[] args) {
        SpringApplication.run(GoodsPoApplication.class, args);
    }

}

Increase control

package com.csdn.GoodsPO.web;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.PathVariable;
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;

@RestController
public class MyController {

    private final RestTemplate restTemplate;

    @Autowired
    public MyController(RestTemplate restTemplate) {this.restTemplate = restTemplate;}

    @RequestMapping(value = "/echo/{str}", method = RequestMethod.GET)
    public String echo(@PathVariable String str) {
        return restTemplate.getForObject("http://GoodsPR/echo/" + str, String.class);
    }
}

Modify goodspr and add control

package com.csdn.GoodsPR.web;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EchoController {
    @RequestMapping(value = "/echo/{string}", method = RequestMethod.GET)
    public String echo(@PathVariable String string) {
        return "Hello Nacos Discovery " + string;
    }
}

Restart the project, browser input: http://192.168.0.148:13732/echo/5231

The project call was successful.