1. Unified configuration management

• Configuration change hot update
  
  

• stay Nacos Add configuration information to ：
  
  

• The steps of configuration acquisition are as follows ：
  

1. introduce Nacos The configuration management client depends on ：

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

2. stay userservice Medium resource Directory add a bootstrap.yml file , This file is the boot file , Priority over application.yml

spring:
  application:
    name: userservice #  The service name 
  profiles:
    active: dev #  development environment 
  cloud:
    nacos:
      server-addr: 47.107.53.146:8848 # nacos  Address 
      config:
        file-extension: yaml #  File suffix 

• stay user-service Lieutenant general pattern.dateformat This attribute is injected into UserController Test in ：

@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() {
    
        return LocalDateTime.now().format(DateTimeFormatter.ofPattern(dateformat));
    }
}

• You can see 8081 and 8082 Both microservices can access the formatted time , Instructions can be from nacos Read the information of the configuration file in the console

• Section ：

1. Give the configuration to Nacos Management steps
2. stay Nacos Add profile to
3. Introduce... Into microservices nacos Of config rely on
4. Add... To microservices bootstrap.yml, To configure nacos Address 、 The current environment 、 The service name 、 File suffix . These determine when the program starts nacos Which file to read

2. Configure auto refresh

• Nacos After the configuration file in is changed , Microservices can sense... Without restarting . However, it needs to be implemented through the following two configurations ：

• change userservice-dev.yaml The configuration file ：
  

1. Mode one ： stay @Value Add an annotation on the class where the injected variable is located @RefreshScope
   

@Component
@Data
@ConfigurationProperties(prefix = "pattern")
public class PatternProperties {
    
    private String dateformat;
}

• You can see that without restarting the service , change nacos The configuration file on can also achieve a consistent effect
  

2. Mode two ： Use @ConfigurationProperties Note in place of @Value annotation .

• The configuration changes are as follows ：
  

• stay user-service In service , Add a class , Read patterrn.dateformat attribute ：

@Component
@Data
@ConfigurationProperties(prefix = "pattern")
public class PatternProperties {
    
    private String dateformat;
}

• UserController add to ：

@Autowired
private PatternProperties properties;

@GetMapping("/now")
public String now() {
    
    return LocalDateTime.now().format(DateTimeFormatter.ofPattern(properties.getDateformat()));
}

• You can see , Modify without restarting the service nacos The configuration file on can also achieve the same effect
  

• Section ：

Nacos After configuration changes , Microservices can achieve hot updates , The way ：
① adopt @Value Annotation injection , combination @RefreshScope To refresh
② adopt @ConfigurationProperties Inject , Automatically refresh

• matters needing attention ：
  Not all configurations fit into the configuration center , Maintenance is more troublesome
  It is suggested that some key parameters , Parameters that need to be adjusted at run time nacos Configuration center , It is generally custom configuration

3. Multi environment configuration sharing

The microservice starts from nacos Read multiple configuration files ：

• [spring.application.name]-[spring.profiles.active].yaml, for example ：userservice-dev.yaml
• [spring.application.name].yaml, for example ：userservice.yaml

No matter what profile How to change ,[spring.application.name].yaml This file must be loaded , Therefore, the multi environment sharing configuration can be written to this file

• newly build userservice.yaml The configuration file is as follows ：
  

• verification userservice.yaml Whether the configured must be read

@Component
@Data
@ConfigurationProperties(prefix = "pattern")
public class PatternProperties {
    
    private String dateformat;
    private String envShareValue;
}

• bootstrap.yml as follows , Express userservice.yaml and userservice-dev.yaml The file must be read
  

@Autowired
private PatternProperties properties;

@GetMapping("prop")
public PatternProperties properties() {
    return  properties;
}

• start-up userservice 8082 Environmental Science , It is amended as follows test Configuration file environment
  

• At this time, this service can only read userservice.yml The configuration file

• userservice 8081 Read as follows
  

• userservice 8082 Read as follows
  

• At this point, these two services can get the shared attribute value , explain userservice.yml The profile properties in are shared
  

• You can also see the information of the read configuration file on the console

• If in nacos Configuration in progress ,userservice.yaml and userservice-dev.yaml The same attribute exists in both configuration files , Which configuration file shall prevail ？ If in idea There are the same profile attributes in , Which one will prevail ？

• Configure the same property both remotely and locally , Test the following ：
  

application.yml

• stay Local plus name Property value

• stay Distal nacos Of userservice.yml add
  

• Access property values , Discovery is based on nacos Upper userservice.yml Subject to
  

• userservice-dev.yml add
  

• test , Find the properties in the local configuration file and Distal userservice.yml 、userservice-dev.yml When both properties exist at the same time , With userservice-dev.yml Subject to
  

• Priority of multiple configurations ：
  

• Section ：

• Microservices will start from nacos Read the configuration file ：
  ①[ service name ]-[spring.profile.active].yaml, Environment configuration
  ②[ service name ].yaml, The default configuration , Multi environment sharing

• priority ：
  ①[ service name ]-[ Environmental Science ].yaml >[ service name ].yaml > Local configuration