Spring Cloud Alibaba Basic Tutorial: Nacos Service Discovery and Configuration Management

With the popularity of the concept of micro-services, more and more companies are adopting Spring Cloudfamily barrel build micro-services systems, achieve rapid iteration of business. Spring CloudIt provides services to quickly build distributed micro commonly used components, including Spring Cloud Eureka, Spring Cloud Ribbon, Spring Cloud Hystrix, Spring Cloud Zuuland so on. Dependent on Springa strong ecological environment, it has become Javadevelopers to build micro-service systems the preferred solution.

This article series, we meet another micro-service solutions Spring Cloud Alibaba. Relying on Alibabastrong technical support, and Eureka2.xno longer maintained and other factors, we believe that the near future Spring Cloud Alibabawill be the better choice for most companies to micro-services practice.

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Next we introduce Nacos service registration discovery and configuration management capabilities.

Nacos committed to helping you discover, configure, and micro-management services. Nacos provides a set of simple-to-use set of features that help you quickly realize dynamic service discovery, service configuration, service metadata and traffic management.

Nacos help you more quickly and easily build, deliver and manage micro-service platform. Nacos is to build a "service" as the center of modern application architectures (such as micro-service paradigm, cloud native paradigm) service infrastructure.

First, find registration

First you need to download Nacos , directly extract the download is complete, the next startNacos

cd nacos/bin
// Linux/Unix/Mac
sh startup.sh -m standalone
// Windows
cmd startup.cmd -m standalone

Above that the use of independent way to start Nacos, start after the completion of access Nacos Home , the default user name and password are nacos

After a successful login, you can see in the following figure

Next, create a service registry toNacos

1. First create a dependent parent project management, pom.xmlas follows

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <modules>
        <module>service-provider</module>
    </modules>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>com.example</groupId>
    <artifactId>spring-cloud-alibaba-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>alibaba-demo</name>
    <packaging>pom</packaging>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.RELEASE</spring-cloud.version>
        <spring-cloud-alibaba.version>2.1.1.RELEASE</spring-cloud-alibaba.version>
    </properties>


    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</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>

1. Then create sub-module service-provider, pom.xmlas follows

<?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>spring-cloud-alibaba-demo</artifactId>
        <groupId>com.example</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>service-provider</artifactId>

    <dependencies>
        <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>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

1. In service-provideradding the module bootstrap.ymlconfiguration file, as follows:

spring:
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
  application:
    name: service-provider
  main:
    allow-bean-definition-overriding: true
server:
  port: 8080

The above configuration specifies service registration address discovery

1. Start Class Code

@EnableDiscoveryClient
@SpringBootApplication
public class ServiceProviderApplication {

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

}

Then start service-provider, to the Nacoslist of services registered already observed up service

By Nacosproviding the Open-API you can see the list of services registered

➜  ~ curl -X GET '127.0.0.1:8848/nacos/v1/ns/service/list?pageNo=1&pageSize=10'
{"count":1,"doms":["service-provider"]}%                                         
➜  ~ 

The basic use of this service has been completed registration, followed by introduction of the use of Configuration Management

Second, configuration management

For convenience, I directly on the service-providerproject to transform the presentation

1. Modify pom.xmlfile

<?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>spring-cloud-alibaba-demo</artifactId>
        <groupId>com.example</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>service-provider</artifactId>

    <dependencies>
        <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>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Added spring-cloud-starter-alibaba-nacos-configdependence

1. modifybootstrap.yml

spring:
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
      config:
        server-addr: ${spring.cloud.nacos.discovery.server-addr}
  application:
    name: service-provider
  main:
    allow-bean-definition-overriding: true
server:
  port: 8080

The above configuration specifies configuration management service address

1. Modify the startup class code

@RefreshScope
@RestController
@EnableDiscoveryClient
@SpringBootApplication
public class ServiceProviderApplication {
    @Value("${config.test}")
    private String testConfigValue;

    @GetMapping("/config")
    public String getConfigValue() {
        return testConfigValue;
    }

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

}

Adding @RefreshScopesupport dynamic configuration updates

1. Add Nacosprofile

Then start the project observed the console log output

2019-12-01 15:44:39.097  INFO 19295 --- [           main] c.a.c.n.c.NacosPropertySourceBuilder     : Loading nacos data, dataId: 'service-provider.properties', group: 'DEFAULT_GROUP', data: config.test=这是一个测试值

You can see the local service has been acquired to Nacosthe data in the configuration management. Attempts to access data interfaces

➜  ~ curl -X GET '127.0.0.1:8080/config'
这是一个测试值%                                                                    
➜  ~ 

The right to acquire the configuration data, then try to modify the configuration data

View the console log

2019-12-01 15:47:25.694  INFO 19295 --- [-127.0.0.1_8848] o.s.c.e.event.RefreshEventListener       : Refresh keys changed: [config.test]

Description has been changed successfully, the service is synchronized to the latest configuration. Attempts to access data interfaces

➜  ~ curl -X GET '127.0.0.1:8080/config'
这是一个测试值-修改后%                                                                    
➜  ~ 

Configure dynamic updates are already in force. Source Project

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