wilkinsona
commented
8 years ago We currently stop the application context and then stop the container. We did try to reverse this ordering but it had some unwanted side effects so we're stuck with it for now at least. That's the bad news.
The good news is that you can actually get a graceful shutdown yourself if you're happy to get your hands a bit dirty. The gist is that you need to pause Tomcat's connector and then wait for its thread pool to shutdown before allowing the destruction of the application context to proceed. It looks something like this:
package com.example;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import org.apache.catalina.connector.Connector;
import org.apache.tomcat.util.threads.ThreadPoolExecutor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
import org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
import org.springframework.context.ApplicationListener;
import org.springframework.context.annotation.Bean;
import org.springframework.context.event.ContextClosedEvent;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@RestController
public class Gh4657Application {
public static void main(String[] args) {
SpringApplication.run(Gh4657Application.class, args);
}
@RequestMapping("/pause")
public String pause() throws InterruptedException {
Thread.sleep(10000);
return "Pause complete";
}
@Bean
public GracefulShutdown gracefulShutdown() {
return new GracefulShutdown();
}
@Bean
public EmbeddedServletContainerCustomizer tomcatCustomizer() {
return new EmbeddedServletContainerCustomizer() {
@Override
public void customize(ConfigurableEmbeddedServletContainer container) {
if (container instanceof TomcatEmbeddedServletContainerFactory) {
((TomcatEmbeddedServletContainerFactory) container)
.addConnectorCustomizers(gracefulShutdown());
}
}
};
}
private static class GracefulShutdown implements TomcatConnectorCustomizer,
ApplicationListener<ContextClosedEvent> {
private static final Logger log = LoggerFactory.getLogger(GracefulShutdown.class);
private volatile Connector connector;
@Override
public void customize(Connector connector) {
this.connector = connector;
}
@Override
public void onApplicationEvent(ContextClosedEvent event) {
this.connector.pause();
Executor executor = this.connector.getProtocolHandler().getExecutor();
if (executor instanceof ThreadPoolExecutor) {
try {
ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
threadPoolExecutor.shutdown();
if (!threadPoolExecutor.awaitTermination(30, TimeUnit.SECONDS)) {
log.warn("Tomcat thread pool did not shut down gracefully within "
+ "30 seconds. Proceeding with forceful shutdown");
}
}
catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
}
}
}I think it makes sense to provide behaviour like this out of the box, or at least an option to enable it. However, that'll require a bit more work as it'll need to work with all of the embedded containers that we support (Jetty, Tomcat, and Undertow), cope with multiple connectors (HTTP and HTTPS, for example) and we'll need to think about the configuration options, if any, that we'd want to offer: switching it on or off, configuring the period that we wait for the thread pool to shutdown, etc.
LutzStrobel
tkvangorder
bohrqiu
thefallentree
clanie
ktracer-isp
czyoshida-naoko
robocide
corentin59
dfjones
MarcoGnecchi
rdramana85
yochentt
nithril
stevenschlansker
renannprado
jorgheymans
penglongli
mlausch1963
hbrands
manuelwallrapp
ghost
rabbitgyk
We are using spring-boot and spring-cloud to realize a micro service archtecture. During load tests we are facing lots of errors such as "entitymanager closed and others" if we shut the micro service down during load. We are wondering if there is an option to configure the embedded container to shut its service connector down and waits for an empty request queue before shutting down the complete application context.
If there is no such option, I did not find any, then it would be great to extend the shutdownhook of spring to respect such requirements.