Order

The relevant configuration of the database will not change frequently in general, especially when the database connection uses domain name instead of ip address, so that even if the ip address changes, the business system will not be affected. Here, let’s talk about whether there is a way to change the configuration without restarting if it is really necessary.

Train of thought

There are many schemes, so let’s talk about the RefreshScope scheme based on SpringCloud.

Database configuration instance

spring:
  datasource:
    platform: postgres
    url: jdbc:postgresql://192.168.99.100:5432/postgres
    driverClassName: org.postgresql.Driver
    username: postgres
    password: 123456
    validation-query: SELECT 1
    test-while-idle: true
    test-on-borrow: true

Java configuration

@Configuration
public class DbConfig {

    @Bean
    @RefreshScope //refresh
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }
}

Update

Just call the refresh endpoint of the service

curl -i -X POST http://localhost:9001/refresh

Verification

@Component
public class ScheduleTask {

    @Autowired
    UserRepository userRepository;

    @Scheduled(fixedDelay = 5*1000 /**ms**/,initialDelay = 5*1000)
    public void testDataSourceConn() {
        try{
            System.out.println("call jdbc");
            userRepository.findAll();
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

Here we run a timed task, constantly calling the data query method, then changing the password in the middle, and then refresh to see if there is an error.

doc

• Refresh Scope