Microservices Engine:Register Spring Cloud applications with MSE Nacos registries

1. Create a Maven project

Create a Maven project named nacos-service-provider.

2. Add dependencies

Add the following to the pom.xml file. This example uses Spring Boot 2.1.4.RELEASE with Spring Cloud Greenwich.SR1.

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.4.RELEASE</version>
    <relativePath/>
</parent>

<dependencies>
    <!-- Nacos service discovery -->
    <dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        <version>2.1.1.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Greenwich.SR1</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>

The Spring Cloud Alibaba version must match the Spring Cloud release:

3. Create the application class

Create a package named com.aliware.edas under src/main/java. Add the following class named ProviderApplication.

The @EnableDiscoveryClient annotation enables service registration and discovery.

package com.aliware.edas;

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

@SpringBootApplication
@EnableDiscoveryClient
public class ProviderApplication {

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

4. Create a REST controller

In the same com.aliware.edas package, create a class named EchoController that maps GET requests to /echo/{string} and returns the path variable.

package com.aliware.edas;

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 string;
    }
}

5. Configure the Nacos registry endpoint

Create a file named application.properties under src/main/resources:

spring.application.name=service-provider
server.port=18081
spring.cloud.nacos.discovery.server-addr=mse.XX.nacos.mse.aliyuncs.com:8848
# To use a custom namespace, uncomment the following line:
# spring.cloud.nacos.discovery.namespace=<namespace-id>

Replace mse.XX.nacos.mse.aliyuncs.com with your MSE Nacos instance's public endpoint. To find this value, open the MSE console, navigate to Microservices Registry > Instances, and locate the endpoint on the instance details page.

6. Verify provider registration

1. Run the main method of ProviderApplication to start the provider.

2. Log in to the MSE console and select a region in the top navigation bar.

3. In the left-side navigation pane, choose Microservices Registry > Instances. Click the instance name.

4. Choose Service Management > Services.

5. On the Services page, confirm that service-provider is listed.

1. Create a Maven project

Create a Maven project named nacos-service-consumer.

2. Add dependencies

Add the following to the pom.xml file. Compared to the provider, the consumer adds spring-cloud-starter-openfeign for declarative REST calls.

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.4.RELEASE</version>
    <relativePath/>
</parent>

<dependencies>
    <!-- Nacos service discovery -->
    <dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        <version>2.1.1.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- Declarative REST client -->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Greenwich.SR1</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>

3. Create the FeignClient interface

Create a package named com.aliware.edas under src/main/java. Add an interface named EchoService with the @FeignClient annotation pointing to service-provider.

package com.aliware.edas;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@FeignClient(name = "service-provider")
public interface EchoService {
    @RequestMapping(value = "/echo/{str}", method = RequestMethod.GET)
    String echo(@PathVariable("str") String str);
}

4. Create the application class

In the same package, create a class named ConsumerApplication with the following annotations:

• @EnableDiscoveryClient -- enables service registration and discovery

• @EnableFeignClients -- enables FeignClient

• @LoadBalanced on the RestTemplate bean -- integrates RestTemplate with service discovery for client-side load balancing

package com.aliware.edas;

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.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class ConsumerApplication {

    @LoadBalanced
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }

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

5. Create a test controller

In the same package, create a class named TestController that exposes two endpoints -- one using RestTemplate and one using FeignClient -- to demonstrate both service discovery methods.

package com.aliware.edas;

import org.springframework.beans.factory.annotation.Autowired;
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 TestController {

    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private EchoService echoService;

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

    @RequestMapping(value = "/echo-feign/{str}", method = RequestMethod.GET)
    public String feign(@PathVariable String str) {
        return echoService.echo(str);
    }
}

6. Configure the Nacos registry endpoint

Create a file named application.properties under src/main/resources:

spring.application.name=service-consumer
server.port=18082
spring.cloud.nacos.discovery.server-addr=mse.XX.nacos.mse.aliyuncs.com:8848
# To use a custom namespace, uncomment the following line:
# spring.cloud.nacos.discovery.namespace=<namespace-id>

Replace mse.XX.nacos.mse.aliyuncs.com with your MSE Nacos instance's public endpoint, as described in Step 1, sub-step 5.

7. Verify consumer registration

1. Run the main method of ConsumerApplication to start the consumer.

2. Log in to the MSE console and select a region in the top navigation bar.

3. In the left-side navigation pane, choose Microservices Registry > Instances. Click the instance name.

4. Choose Service Management > Services.

5. On the Services page, confirm that service-consumer is listed.

Services do not appear in the MSE console after registration

By default, the public IP address whitelist is set to 127.0.0.1/32, which blocks all external access. Add the public IP addresses of your provider and consumer machines to the whitelist. See Configure a public IP address whitelist.

Which Spring Cloud versions does MSE support?

Spring Cloud Edgware is discontinued. Do not use it for new applications.