0. Question introduction

Previous microservice architecture ：

But as the business grows , We may need to deploy dozens or even hundreds of microservices , But then there is a problem , If you want to add a business or modify a business now , For this business, you need to modify the configuration files of multiple microservices , It's ok if there are several configuration files to modify , But if there are many , This undoubtedly increases our workload . And after modifying the configuration , We also need to restart various micro Services , Hot updates that do not allow configuration changes …

At this time, a configuration management service is used to manage the configuration or core configuration of these micro services that are often changed , When the configuration needs to be modified , It is good to directly change the configuration of the configuration center to the micro service to read and combine its own configuration , The overall structure is shown in the figure below ：

It's reflected here Nacos Is powerful , He is in configuration management ： On the one hand, the configuration can be managed centrally , The other party can change the configuration , Timely notify the microservice , Hot update of configuration .

1. Nacos Configuration Management

Nacos It can not only be used as a registration center 、 It can also be used as a configuration center .

The structure diagram is as follows ：

So how do we get there nacos Add configuration files in ？ Now let's explore ：

1.1. Unified configuration management

When there are more and more instances of microservice deployment , Up to dozens 、 Hundreds of hours , Modifying the microservice configuration one by one will drive people crazy , And it's easy to make mistakes . We need a unified configuration management solution , You can centrally manage the configuration of all instances .

Nacos On the one hand, the configuration can be managed centrally , The other party can change the configuration , Timely notify the microservice , Hot update of configuration .

The structure flow chart is as follows ：

1.1.1. stay nacos Add profile to

Click on the configuration list , Click the plus sign on the right

Then add the configuration page to set the information of the configuration items , for example ：

Click Add , At this point, we have one more configuration ：

Be careful ： The core configuration of the project , Configurations that require hot updates are available nacos The need for management . It is better to save some configurations that will not be changed locally in the microservice .

1.1.2. Pull the configuration from the microservice

The micro service needs to pull nacos Configuration managed in , And with local application.yml Configuration merge , To complete the project launch .

But there is another problem ： If not already read application.yml, How do you know nacos The address? ？

therefore spring A new configuration file is introduced ：bootstrap.yaml file , Will be in application.yml Previously read , The process is as follows ：

1.1.3. Pull the configuration steps from the microservice ：

1） introduce nacos-config rely on
First , stay user-service In service , introduce nacos-config Client dependency for ：

<!--nacos Configuration management dependency -->
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>

2） add to bootstrap.yaml

then , stay user-service Add a bootstrap.yaml file , The contents are as follows ：

spring:
  application:
    name: userservice #  The service name 
  profiles:
    active: dev # development environment , Here is dev 
  cloud:
    nacos:
      server-addr: localhost:8848 # Nacos Address 
      config:
        file-extension: yaml #  File suffix 

It will be based on spring.cloud.nacos.server-addr obtain nacos Address , According to

${spring.application.name}-${spring.profiles.active}.${spring.cloud.nacos.config.file-extension} As a document id, To read the configuration .

The file name here is ：userservice-dev.yaml, That is the configuration we just added in the configuration center

3） Read nacos To configure

stay user-service Medium UserController Add business logic , Read pattern.dateformat To configure ：

Complete code ：

package com.yyl.user.web;

import com.yyl.user.pojo.User;
import com.yyl.user.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

@Slf4j
@RestController
@RequestMapping("/user")
public class UserController {
    

    @Autowired
    private UserService userService;

    @Value("${pattern.dateformat}")
    private String dateformat;
    
    /** *  route ： /user/110 * @param id  user id * @return  user  */
    @GetMapping("/{id}")
    public User queryById(@PathVariable("id") Long id) {
    
        return userService.queryById(id);
    }

    
    @GetMapping("now")
    public String now(){
    
    	//  Get the current time and format 
        return LocalDateTime.now().format(DateTimeFormatter.ofPattern(dateformat));
    }
}

Request access , You can see the effect ：

perfect ！