Nacos shared configuration

This article introduces how to read the shared configuration when Nacos is used as the configuration center

my environment

• Windows10
• JDK8
• SpringCloud：Finchley.RELEASE
• SpringBoot：2.0.4.RELEASE
• spring-cloud-alibaba-dependencies：0.2.2.RELEASE
• Nacos-server：1.0.1

The project Demo in this article continues to use the aggregation project in the previous article Nacos. If you don’t have the previous environment, you can download it from the source code address

scene description

After the number of services in a project increases, the configuration files increase accordingly. There will be the same configuration in multiple configuration files, then we can separate the same configuration as a shared configuration file for each service in the project. Each service can Read shared configuration through Nacos

Let's use a demo to demonstrate whether it is feasible

• demo project: nacos-config-share
• Configuration file: nacos-config-share.yml
• Share configuration files: shareconfig1.yml, shareconfig2.yml

create project

As usual, create a subproject named under the aggregation project Nacos nacos-config-share, and its pom.xml file depends on the same as the previous project. If you do not have the previous project, you can refer to the source code address

1. Modify the springboot startup classNacosConfigShareApplication.java

@SpringBootApplication
@EnableDiscoveryClient
@RestController
@RefreshScope
public class NacosConfigShareApplication {

@SpringBootApplication
@EnableDiscoveryClient
@RestController
@RefreshScope
public class NacosConfigShareApplication {

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

    @Value("${nacos.share}")
    private String share;


    @Value("${share.config1}")
    private String shareConfig1;

    @Value("${share.config2}")
    private String shareConfig2;

    @RequestMapping("/getValue")
    public String getValue() {
        return share;
    }

    @RequestMapping("/getShare1")
    public String getShare1() {
        return shareConfig1;
    }

    @RequestMapping("/getShare2")
    public String getShare2() {
        return shareConfig2;
    }
}

2. Modify the configuration file of the projectbootstrap.yml

spring:
  application:
    name: nacos-config-share
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
      config:
        server-addr: 127.0.0.1:8848
        prefix: ${spring.application.name}
        file-extension: yml
        shared-dataids: shareconfig1.yml,shareconfig2.yml
        refreshable-dataids: shareconfig1.yml,shareconfig2.yml

It can be seen from the configuration file that shared-dataidsthe shared configuration file to be read is specified through attributes DataID, and multiple files are ,separated
by using refreshable-dataidsthe specified shared configuration file to support automatic refresh

New configuration file

Here we use it as a demonstration, without joining the Namespace, and create and test directly in the public space

Create a configuration file nacos-config-share.yml, as detailed below:

• DataId:nacos-config-share.yml
• Configuration format:YAML
• Configuration content:

  server:
      port: 9984
  nacos: 
      share: nacos-config-share
  

Create a shared configuration file 1 shareconfig1.yml, the details are as follows:

• DataId:shareconfig1.yml
• Configuration format:YAML
• Configuration content:

  share: 
      config1: 这里是共享配置文件1
  

Create a shared configuration file 1 shareconfig2.yml, the details are as follows:

• DataId:shareconfig2.yml
• Configuration format:YAML
• Configuration content:

  share: 
      config2: 这里是共享配置文件2
  

After the creation is successful, the configuration list is as follows:

start test

Start the project directly, if the startup is successful. You can see the following information in the log:

Access the interface provided in the startup class, and test whether the value in the shared configuration file can be obtained

访问127.0.0.1:9984/getValue,返回：nacos-config-share
访问127.0.0.1:9984/getShare1,返回：这里是共享配置文件1
访问127.0.0.1:9984/getShare2,返回：这里是共享配置文件2

Then test refreshable-dataidswhether the configured automatic refresh takes effect

Modify the value of the shared configuration file in the Nacos console shareconfig2.yml:这里是共享配置文件2这里是共享配置文件2

After editing and saving, request 127.0.0.1:9984/getShare2 again, and observe the returned results as follows:

Shared profile 2 here Shared profile 2 here

The above returned results show that the shared configuration file can be read and automatically refreshed by specifying shared-dataidsand in the configuration file .refreshable-dataids

change of requirements

shareconfig3.ymlSuppose you want to read and file now shareconfig4.ymlbut its Group is SHARE3_GROUPand SHARE4_GROUP, that is, the shared configuration file is not in the same group as the project’s own configuration file ( 上边的例子是全都在DEFAULT_GROUP分组), then if you continue to use the above method, you will not be able to read the shared configuration file

At this time, another configuration can be used ext-config, which can be customized by the user to specify the configuration to be loadedDataID、Group以及是否自动刷新

And ext-configit is a collection ( List) that supports the specification of multiple configuration files.

Create a new shared profile

First create configuration configuration files shareconfig3.ymland shareconfig4.ymlpay attention to their Group attributes

• DataId:shareconfig3.yml
• Group：SHARE3_GROUP
• Configuration format:YAML
• Configuration content:

  share: 
      config3: 这里是共享配置文件3，Group:SHARE3_GROUP
  

• DataId:shareconfig4.yml
• Group：SHARE4_GROUP
• Configuration format:YAML
• Configuration content:

  share: 
      config4: 这里是共享配置文件4，Group:SHARE4_GROUP
  

Create a successful page as follows:

Modify project code

1. NacosConfigShareApplication.javaAdd the following code in the startup class

    @Value("${share.config3}")
    private String shareConfig3;

    @Value("${share.config4}")
    private String shareConfig4;


    @RequestMapping("/getShare3")
    public String getShare3() {
        return shareConfig3;
    }

    @RequestMapping("/getShare4")
    public String getShare4() {
        return shareConfig4;
    }

2. Modify the project configuration file bootstrap.ymland add ext-configconfiguration

spring:
  application:
    name: nacos-config-share
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
      config:
        server-addr: 127.0.0.1:8848
        prefix: ${spring.application.name}
        file-extension: yml
        shared-dataids: shareconfig1.yml,shareconfig2.yml
        refreshable-dataids: shareconfig1.yml,shareconfig2.yml
        ext-config:
          - data-id: shareconfig3.yml
            group: SHARE3_GROUP
            refresh: true
          - data-id: shareconfig4.yml
            group: SHARE4_GROUP
            refresh: true

Start for testing

After the project has been modified, you can see

1. The nacos configuration file of the project itself belongs to DEFAULT_GROUP, which is read by default
2. shareconfig1.yml, shareconfig2.yml belong to DEFAULT_GROUP, shared-dataidsread by specifying
3. shareconfig3.yml and shareconfig4.yml belong to 非DEFAULT_GROUPthe following, and ext-configcan be customized and read through configuration properties

Start the project and test whether all configuration files can be read normally

访问127.0.0.1:9984/getValue,返回：nacos-config-share
访问127.0.0.1:9984/getShare1,返回：这里是共享配置文件1
访问127.0.0.1:9984/getShare2,返回：这里是共享配置文件2这里是共享配置文件2
访问127.0.0.1:9984/getShare3,返回：这里是共享配置文件3，Group:SHARE3_GROUP
访问127.0.0.1:9984/getShare4,返回：这里是共享配置文件4，Group:SHARE4_GROUP

The modified shareconfig4.ymlconfiguration content is: 这里是共享配置文件4，Group:SHARE4_GROUP,支持自动刷新, after saving, call 127.0.0.1:9984/getShare4 again, and the return is as follows:

Here is shared configuration file 4, Group: SHARE4_GROUP, supports automatic refresh

After calling the interface, it is found that the loading methods of the two shared configurations can be read normally and can be used together. ext-configThe way to achieve user-defined configuration shared configuration files.

Summarize

The above demo has demonstrated two implementations of Nacos shared configuration. The two methods are aimed at different scenarios and are summarized as follows:

• shared-dataidsWay:
  • It is suitable for when the shared configuration file and the project default configuration file are in the same group, and it can be done directly with two commands
  • Advantages: easy configuration
  • Disadvantage: only in the same group
• ext-configWay:
  • It allows the developer to customize the DataId, Group, and refresh attributes of the shared configuration file to be read, which just solves the shared-dataidsexisting limitations.
  • Advantages: Can shared-dataidsbe used in conjunction with the program, user-defined configuration. Strong flexibility
  • Disadvantages: configuration is error-prone, familiar with YAML syntax

It can be seen that the two methods have their own advantages, so if you need to use shared configuration during development, you can choose the most suitable solution according to your specific situation.

Source code of this article : https://github.com/larscheng/larscheng-learning-demo/tree/master/Nacos