Nacos service configuration and persistence configuration

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One 、Nacos The service registry has been improved

Service registration and discovery framework	CAP Model	Console management	Community activity
Eureka	AP	Support	low (2.x Version closed source )
Zookeeper	CP	I won't support it	in
Consul	CP	Support	high
Nacos	AP	Support	high

CAP Model

• Uniformity （Consistency）： The instance of the same request at the same time returns the same result , All data should be consistent (Strong Consistency)
• Usability （Availability）： The read and write requests of all instances can get correct responses within a certain period of time
• Partition tolerance （Partition tolerance）： In the network exception （ The cable is broken 、 Equipment failure 、 Downtime ） Under the circumstances , The system can still provide normal service

The above three characteristics are CAP principle （ also called CAP Theorem ）, But the three characteristics cannot be satisfied at the same time , Therefore, the design of distributed system should consider meeting P（ Partition tolerance ） On the premise of C（ Uniformity ） still A（ Usability ）, namely ：CP or AP.

Two 、Nacos Service configuration center

1. Add dependency

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
    <version>2021.1</version>
</dependency>
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
    <version>2021.1</version>
</dependency>

2. To configure application.yaml

spring:
  profiles:
    active: dev # Represents the development environment 

3. To configure bootstrap.yaml

# nacos To configure 
server:
  port: 3377
spring:
  application:
    name: nacos-config-client
  cloud:
    nacos:
      discovery: # register 
        server-addr:
          localhost: 8848 #Nacos Address of service registration center 
      config: # Open configuration center 
        server-addr:
          localhost: 8848 #Nacos As the configuration center address 
        file-extension: yaml # Appoint yaml Format configuration 

#  Official format 
# ${prefix}-${spring.profiles.active}.${file-extension}
# ${spring.application.name}-${spring.profiles.active}.${file-extension}

#  The actual format 
# nacos-config-client-dev.yaml

4. Platform creation configuration rules

5. The business layer writes

@RestController
@RefreshScope // Support Nacos Dynamic refresh function 
public class ConfigClientController {
    
    @Value("${config.info}")
    private String configInfo;
    @GetMapping("/config/info")
    public String getConfigInfo(){
    
        return configInfo;
    }
}

6. Access to get configuration content

7. Nacos Dynamic refresh （@RefreshScope annotation ）

Notes introduced by the business layer @RefreshScope Support Nacos Dynamic refresh function

3、 ... and 、 Switch between different environments

1. DateId programme

First, follow the previous steps , Create two configurations on the platform （dev and test）

Restart project , Test whether to switch to test Configuration of the environment

2. Group programme

Group The default grouping is DEFAULT_GROUP, So we need to divide into two groups ： One group is dev Development Group , One group is test Test group
View the configuration list , Check if the configuration is successful

change application.yaml and bootstrap.yaml The configuration file , test info Under the test:

revisit , Check whether the switch is successful

3. Namespace Space programme

newly build test and dev Two namespaces




Modify the configuration file
The manual in test Create three new groups under namespace

Access test

Four 、Nacos Persistent configuration

1. derby database

Nacos Embedded database will be provided by default in derby, So we create one at a time Nacos The instance will have one derby, When there is more than one Nacos Node time , There will be consistency issues , therefore Nacos Support unified management of external databases MySql.

2. Switch MySql database

① Create database

Create... In the database nacos_config library
CREATE DATABASE nacos_config;

② Execute... In the database navos-mysql.sql Script

The following table will appear in the Library ：

③ modify application.properties file

spring.datasource.platform=mysql

db.num=1
db.url.0=jdbc:mysql://11.162.196.16:3306/nacos_devtest?characterEncoding=utf8&connectTimeout=1000&socketTimeout=3000&autoReconnect=true&serverTimezone=UTC
db.user=nacos_devtest
db.password=youdontknow

④ test

start-up nacos

The new configuration

Look at the local database , Data exists , Description switch mysql Database success ！