Should the Spring Boot shutdown endpoint shut down the entire JVM process, or just the application context? - spring-boot

Question

I am getting a 200 response from Spring Boot's shutdown endpoint, and I am seeing that the application context shuts down as expected, but then the JVM process itself remains alive forever. Is this the expected behavior of the shutdown endpoint, or is it expected that the process itself would also terminate gracefully?
In http://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-endpoints.html, it says that the shutdown endpoint "allows the application to be gracefully shutdown (not enabled by default)".

Answer 1

Thanks Stéphane, I found what was preventing the JVM process from terminating after hitting the /shutdown endpoint. There was a ScheduledExecutor in one of my dependencies that was not being shut down with the application context, and it was preventing the JVM process from shutting down (even after the application context was closed). I wrote a simple example to show how to reproduce the behavior, and another example showing how to resolve it.
This example will NOT terminate the JVM process when you hit /shutdown endpoint:
#SpringBootApplication
public class AppSpringConfiguration {
public static void main(String[] args) {
SpringApplication.run(AppSpringConfiguration.class);
}
#Bean
public ClassWithExecutor ce() {
return new ClassWithExecutor();
}
#PostConstruct
public void startScheduledTask() {
ce().startScheduledTask();
}
#RestController
public static class BusinessLogicController {
#RequestMapping(value = "/hi")
public String businessLogic() {
return "hi";
}
}
public static class ClassWithExecutor {
ScheduledExecutorService es;
ClassWithExecutor() {
this.es = Executors.newSingleThreadScheduledExecutor();
}
public void startScheduledTask() {
es.scheduleAtFixedRate(new Runnable() {
#Override
public void run() {
System.out.println("Printing this every minute");
}
}, 0, 3, TimeUnit.SECONDS);
}
}
}
By adding a shutdown hook that shuts down the ScheduledExecutor when the application context is closing, the JVM process now gets terminated after hitting the /shutdown endpoint:
#SpringBootApplication
public class AppSpringConfiguration {
public static void main(String[] args) {
SpringApplication.run(AppSpringConfiguration.class);
}
#Bean
public ClassWithExecutor ce() {
return new ClassWithExecutor();
}
#Bean
ShutdownAction sa() {
return new ShutdownAction(ce());
}
#PostConstruct
public void startScheduledTask() {
ce().startScheduledTask();
}
#RestController
public static class BusinessLogicController {
#RequestMapping(value = "/hi")
public String businessLogic() {
return "hi";
}
}
public static class ShutdownAction implements ApplicationListener<ContextClosedEvent> {
private ClassWithExecutor classWithExecutor;
ShutdownAction(ClassWithExecutor classWithExecutor) {
this.classWithExecutor = classWithExecutor;
}
#Override
public void onApplicationEvent(ContextClosedEvent event) {
classWithExecutor.shutdown();
}
}
public static class ClassWithExecutor {
ScheduledExecutorService es;
ClassWithExecutor() {
this.es = Executors.newSingleThreadScheduledExecutor();
}
public void startScheduledTask() {
es.scheduleAtFixedRate(new Runnable() {
#Override
public void run() {
System.out.println("Printing this every minute");
}
}, 0, 3, TimeUnit.SECONDS);
}
public void shutdown() {
es.shutdownNow();
}
}
}

Answer 2

You have something that prevents the JVM to exit besides your Spring Boot application. If you don't and you have a sample projet that demonstrates the problem, then please create an issue and we'll have a look.
Instead of using the shutdown endpoint, you can use the spring-boot-maven-plugin as of 1.3 that has a start and stop goals to be used in typical integration tests scenarios.

Answer 3

If you have a scheduled executor running you should specify destroy method:
#Bean(destroyMethod = "shutdown")