Learning of springboot+springcloud - Nacos configuration management

In addition to being a registration center, Nacos can also be used for configuration management.

1. Unified configuration management

multiple servicessame configurationor needDynamically adjusted configuration, can be handed over to a unified configuration center for management, and the service pulls the configuration from the configuration center,

If you need to modify the configuration, you only need to modify the configuration in the configuration center to implement batch and dynamic configuration updates of services.

Add configuration files in nacos

The microservice needs to pull the configuration managed in nacos and merge it with the local application.yml configuration to complete the project startup. If the application.yml has not obtained the attributes, the project startup will report an error and the attribute parsing exception

Spring introduces a new configuration file: bootstrap.yaml file, which will be read before application.yml, the process is as follows

read configuration

Introduce nacos-config dependency
In user-service service, import nacos-config client dependency:

<!--nacos配置管理依赖-->
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>

Add bootstrap.yaml (service name, environment, configuration center address, file extension)
to read the configuration in the code
Then, add a bootstrap.yaml file in user-service, the content is as follows:

spring:
  application:
    # 服务名
    name: user-service
  profiles:
    # 环境
    active: dev
  cloud:
    nacos:
      # nacos 服务端地址
      server-addr: localhost:8848
      config:
        # 文件扩展名
        file-extension: yaml

Access test
Add business logic to UserController in user-service, read jdbc.usernameconfiguration:

@Value("${jdbc.username}")
private String username;

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

2. Configure automatic refresh

Requirement: After modifying the configuration in nacos, the microservice can make the configuration take effect without restarting, that is, configuration hot update .

To achieve configuration hot update, two methods can be used:

Method 1: @ValueWhere to 类上add@RefreshScope

Method 2: Use @ConfigurationPropertiesannotations to read configuration

way 1

Add the annotation @RefreshScope to the class where the variable injected by @Value is located:

@RestController
@RequestMapping("/user")
@RefreshScope //刷新配置
public class UserController {
    
    

way 2

Read configuration using @ConfigurationPropertiesannotations

In the user-service service, add a class to read the jdbc.username property:

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@Data
@Configuration
@ConfigurationProperties(prefix = "jdbc")
public class JdbcProperties {
    
    

    private String username;
    private String password;
}

Use this class in UserController:

@Autowired
JdbcProperties jdbcProperties;

@GetMapping("/config")
public String config(){
    
    

    return jdbcProperties.toString();
}

3. Multi-environment configuration

During the development process, the same set of configurations may have different configuration values ​​in different environments (dev, test, prod...), how to switch configurations in multiple environments?
demo

1), nacos configuration center adds the configuration of the test environment

2), modify the current environment

Remember to change dev to test

3), test

4. Configuration sharing

When different environments have the same configurations, these configurations are configured in the configuration file of each environment, and duplicate configurations appear at this time

How to configure it only once, but also share the configuration in multiple environments?

In fact, when the microservice starts, it will go to nacos to read two configuration files, for example:

• Environment configuration: [spring.application.name]-[spring.profiles.active].yaml, for example: user-service-dev.yaml
• Shared configuration: [spring.application.name].yaml, for example: user-service.yaml

1) Add shared configuration

Add shared configuration: add one in nacosuser-service.yamlFile:

At this time, there are 3 configuration files for user services in nacos:

2) Read shared configuration

In the user-service service, modify the UserController class to read the newly added properties:

//读取公共配置
@Value("${user.auth}")
private Boolean auth;

@Autowired
JdbcProperties jdbcProperties;

@GetMapping("/config")
public String config(){
    
    
    //return username;
    return jdbcProperties.getUsername()+" - "+auth;
}

After that it can be tested.

When nacos and service local have the same attribute at the same time, the priority is divided into high and low: the lowest is the local configuration

5. Configuration isolation

Step 1: Create a new namespace

• The default namespace has only one public
  
• Create two new namespaces dev and test
  
  

Step 2: Add configuration

• Add user-service.yaml
  
  

Step 3: Add configuration to the development environment

Add user-service.yaml

Step 4: Read configuration

User service reads test environment configuration

• The configuration file bootstrap.yml reads the specified namespace and group

spring:
  application:
    # 服务名
    name: user-service
  #profiles:
    #active: dev # 不需要指定，namespace指定的就是对应环境
  cloud:
    nacos:
      # nacos 服务端地址
      server-addr: localhost:8848
      config:
        file-extension: yaml # 文件扩展名
        namespace: 42b87aee-ed82-4b07-ad0d-6138cf4c0c24 # test 环境的namespace
        group: USER_GROUP # 组名 区分大小写

Step Five: Test

…

Shared configuration under namespace

Add shared configuration to the test environment in nacos

Add configuration in bootstrap.yml

spring:
  cloud:
    nacos:
      config:
        server-addr: 127.0.0.1:8848
        file-extension: yaml
        namespace: c05434f9-5d25-49ba-be6e-862b21380d25
        group: USER_GROUP
        # 主要是下面这个配置
        # 当前namespace 下各个service 都共享的配置
        shared-configs: 
          - data-id: common.yaml
            group: COMMON_GROUP
            refresh: true  #是否支持应用中可动态刷新， 默认是不支持的。

Test afterwards.