Programmatically Shut Down Spring Boot Application

Programmatically shut down Spring Boot application

Closing a SpringApplication basically means closing the underlying ApplicationContext. The SpringApplication#run(String...) method gives you that ApplicationContext as a ConfigurableApplicationContext. You can then close() it yourself.

For example,

@SpringBootApplication
public class Example {
    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(Example.class, args);
        // ...determine it's time to shut down...
        ctx.close();
    }
}

Alternatively, you can use the static SpringApplication.exit(ApplicationContext, ExitCodeGenerator...) helper method to do it for you. For example,

@SpringBootApplication
public class Example {
    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(Example.class, args);
        // ...determine it's time to stop...
        int exitCode = SpringApplication.exit(ctx, new ExitCodeGenerator() {
            @Override
            public int getExitCode() {
                // no errors
                return 0;
            }
        });

        // or shortened to
        // int exitCode = SpringApplication.exit(ctx, () -> 0);

        System.exit(exitCode);
    }
}

How to shut down a Spring Boot command-line application

The answer depends on what it is that is still doing work. You can probably find out with a thread dump (eg using jstack). But if it is anything that was started by Spring you should be able to use ConfigurableApplicationContext.close() to stop the app in your main() method (or in the CommandLineRunner).

How to gracefully shutdown the spring boot application

Ultimately the spring boot application spins off a java process which needs to be killed. At present you are killing it manually.

You have a few options:

1. You can use SpringApplication.exit(ApplicationContext, ExitCodeGenerator...) method.
2. If your application is not a long running application then do you have some exit point where your application should stop. At that point you can System.exit(0)
3. You can use external manager tools, for example on unix you can use supervisor, here is a blog you can read about this.
4. SpringApplication.run gives you ApplicationContext which you can close.

how to close the application during startup in spring boot

We have a lot of options to shutdown spring-boot application:

Shutdown rest endpoint - add below properites to your application.properties and fire following request curl -X POST localhost:port/actuator/shutdown

management.endpoints.web.exposure.include=*  
management.endpoint.shutdown.enabled=true  
endpoints.shutdown.enabled=true

Also you can call suitable method to shutdown application:

• By calling method close() on ConfigurableApplicationContext object (it will close application context)
• By passing exit code to method SpringApplication.exit(ctx, () -> 0);

Please check this article for more details.

Is it possible to get a list of service that dynamically get down on my application that is on spring boot

Spring Boot actuator provides a lot of useful endpoints, one of which is the health endpoint. The health endpoint returns the health status of your application based on its dependencies (databases, third party APIs, ...).

There are already builtin health indicators for RabbitMQ, Hazelcast and Elastic. There is no builtin health indicator for DynamoDB as far as I know, but you can also write your own health indicator, as seen in this question.

Now, to send you an email there are a two options:

1. You can use an external program (eg. monitoring software) to regularly check the health actuator
2. You can write it as part of your Spring boot application

Using an external program

If you use an external program, you can make it consume the /actuator/health endpoint. To enable this endpoint, configure the following property:

management.endpoints.web.exposure.include=health

By default this endpoint only exposes a single aggregated status of all health indicators combined. If you want to individually see which service is down, you can show more details by setting the following property to always or when_authorized:

management.endpoint.health.show-details=always | when_authorized

The response will look something like this:

{
  "status": "DOWN",
  "rabbit": {
    "status": "DOWN",
    "error": "org.springframework.amqp.AmqpConnectException: java.net.ConnectException: Connection refused (Connection refused)"
  }
}

Writing your own

You can write a scheduled task by using the @Scheduled annotation to regularly check the health status. To obtain the health status, you can autowire HealthEndpoint as seen in this question.

Then you can send an email with Spring.

@Component
public class HealthEmailSender {
    private final HealthEndpoint healthEndpoint;
    private final JavaMailSender mailSender;

    // TODO: Implement constructor to autowire healthEndpoint + mailSender

    @Scheduled(fixedRate = 10 * 60 * 1000) // Check once every 10 minutes
    public void sendEmailWhenBadHealth() {
        if (isHealthDown()) {
            sendMail();
        }
    }
    
    private boolean isHealthDown() {
        return Status.DOWN.equals(healthEndpoint.health().getStatus());
    }

    private void sendMail() {
        MimeMessage message = mailsender.createMimeMessage();
        // TODO: Set from / to / title / content
        mailSender.send(message);
    }
}

This code snippet above would send an e-mail as soon as any health indicator goes down (not only from the services you mentioned).

To obtain the health status of one of the services you're interested in, you can use healthEndpoint.healthForPath("rabbit").getStatus().

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