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Shutdown hook alignment Níma and MP. (#5913)
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Keep logging system active until shutdown hook completes.
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@tomas-langer
tomas-langer authored Jan 23, 2023
1 parent 25801dd commit 4d828a0
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Showing 4 changed files with 162 additions and 35 deletions.
120 changes: 87 additions & 33 deletions microprofile/cdi/src/main/java/io/helidon/microprofile/cdi/HelidonContainerImpl.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2019, 2022 Oracle and/or its affiliates.
* Copyright (c) 2019, 2023 Oracle and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand All @@ -17,9 +17,11 @@

import java.lang.annotation.Annotation;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;
import java.util.UUID;
Expand Down Expand Up @@ -92,6 +94,8 @@ final class HelidonContainerImpl extends Weld implements HelidonContainer {
private static final String EXIT_ON_STARTED_KEY = "exit.on.started";
private static final boolean EXIT_ON_STARTED = "!".equals(System.getProperty(EXIT_ON_STARTED_KEY));
private static final Context ROOT_CONTEXT;
// whether the current shutdown was invoked by the shutdown hook
private static final AtomicBoolean FROM_SHUTDOWN_HOOK = new AtomicBoolean();

static {
HelidonFeatures.flavor(HelidonFlavor.MP);
Expand All @@ -107,8 +111,10 @@ final class HelidonContainerImpl extends Weld implements HelidonContainer {
CDI.setCDIProvider(new HelidonCdiProvider());
}

private static volatile Thread shutdownHook;
private final WeldBootstrap bootstrap;
private final String id;

private HelidonCdi cdi;

HelidonContainerImpl() {
Expand Down Expand Up @@ -303,39 +309,10 @@ private HelidonContainerImpl doStart() {
// let's add a Handler
// this is to workaround https://bugs.openjdk.java.net/browse/JDK-8161253

Thread shutdownHook = new Thread(() -> {
cdi.close();
}, "helidon-cdi-shutdown-hook");

Logger rootLogger = LogManager.getLogManager().getLogger("");
Handler[] handlers = rootLogger.getHandlers();
Handler[] newHandlers = new Handler[handlers.length + 1];
newHandlers[0] = new Handler() {
@Override
public void publish(LogRecord record) {
// noop
}

@Override
public void flush() {
// noop
}
shutdownHook = new Thread(new CdiShutdownHook(cdi),
"helidon-cdi-shutdown-hook");

@Override
public void close() throws SecurityException {
try {
shutdownHook.join();
} catch (InterruptedException ignored) {
}
}
};
System.arraycopy(handlers, 0, newHandlers, 1, handlers.length);
for (Handler handler : handlers) {
rootLogger.removeHandler(handler);
}
for (Handler newHandler : newHandlers) {
rootLogger.addHandler(newHandler);
}
keepLoggingActive(shutdownHook);

bm.getEvent().select(Initialized.Literal.APPLICATION).fire(new ContainerInitialized(id));

Expand All @@ -351,6 +328,35 @@ public void close() throws SecurityException {
return this;
}

private void keepLoggingActive(Thread shutdownHook) {
Logger rootLogger = LogManager.getLogManager().getLogger("");
Handler[] handlers = rootLogger.getHandlers();

List<Handler> newHandlers = new ArrayList<>();

boolean added = false;
for (Handler handler : handlers) {
if (handler instanceof KeepLoggingActiveHandler) {
// we want to replace it with our current shutdown hook
newHandlers.add(new KeepLoggingActiveHandler(shutdownHook));
added = true;
} else {
newHandlers.add(handler);
}
}
if (!added) {
// out handler must be first, so other handlers are not closed before we finish shutdown hook
newHandlers.add(0, new KeepLoggingActiveHandler(shutdownHook));
}

for (Handler handler : handlers) {
rootLogger.removeHandler(handler);
}
for (Handler newHandler : newHandlers) {
rootLogger.addHandler(newHandler);
}
}

private void exitOnStarted() {
LOGGER.info(String.format("Exiting, -D%s set.", EXIT_ON_STARTED_KEY));
System.exit(0);
Expand Down Expand Up @@ -395,6 +401,13 @@ public void close() {
IN_RUNTIME.set(false);
// need to reset - if somebody decides to restart CDI (such as a test)
ContainerInstanceHolder.reset();

if (!FROM_SHUTDOWN_HOOK.get()) {
Thread thread = shutdownHook;
if (thread != null) {
Runtime.getRuntime().removeShutdownHook(thread);
}
}
}

@Override
Expand Down Expand Up @@ -443,4 +456,45 @@ private BeanDeploymentArchive getArchive(Deployment deployment) {
return deployment.loadBeanDeploymentArchive(WeldContainer.class);
}
}

private static final class CdiShutdownHook implements Runnable {
private final HelidonCdi cdi;

private CdiShutdownHook(HelidonCdi cdi) {
this.cdi = cdi;
}

@Override
public void run() {
LOGGER.info("Shutdown requested by JVM shutting down");
FROM_SHUTDOWN_HOOK.set(true);
cdi.close();
LOGGER.info("Shutdown finished");
}
}
private static final class KeepLoggingActiveHandler extends Handler {
private final Thread shutdownHook;

private KeepLoggingActiveHandler(Thread shutdownHook) {
this.shutdownHook = shutdownHook;
}

@Override
public void publish(LogRecord record) {
// noop
}

@Override
public void flush() {
// noop
}

@Override
public void close() {
try {
shutdownHook.join();
} catch (InterruptedException ignored) {
}
}
}
}
1 change: 1 addition & 0 deletions microprofile/server/src/main/java/io/helidon/microprofile/server/ServerCdiExtension.java
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,7 @@ public class ServerCdiExtension implements Extension {
private final Map<Bean<?>, RoutingConfiguration> serviceBeans = Collections.synchronizedMap(new IdentityHashMap<>());
// build time
private WebServer.Builder serverBuilder = WebServer.builder()
.shutdownHook(false) // we use a custom CDI shutdown hook in HelidonContainerImpl
.port(7001);

private HttpRouting.Builder routingBuilder = HttpRouting.builder();
Expand Down
74 changes: 72 additions & 2 deletions nima/webserver/webserver/src/main/java/io/helidon/nima/webserver/LoomServer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
package io.helidon.nima.webserver;

import java.lang.management.ManagementFactory;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
Expand All @@ -31,6 +32,10 @@
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.function.Consumer;
import java.util.logging.Handler;
import java.util.logging.LogManager;
import java.util.logging.LogRecord;
import java.util.logging.Logger;

import io.helidon.common.Version;
import io.helidon.common.context.Context;
Expand Down Expand Up @@ -172,7 +177,11 @@ public Context context() {
}

private void stopIt() {
parallel("stop", ServerListener::stop);
// We may be in a shutdown hook and new threads may not be created
for (ServerListener listener : listeners.values()) {
listener.stop();
}

running.set(false);

LOGGER.log(System.Logger.Level.INFO, "Níma server stopped all channels.");
Expand Down Expand Up @@ -210,13 +219,19 @@ private void startIt() {

private void registerShutdownHook() {
this.shutdownHook = new Thread(() -> {
LOGGER.log(System.Logger.Level.INFO, "Shutdown requested by JVM shutting down");
listeners.values().forEach(ServerListener::stop);
if (startFutures != null) {
startFutures.forEach(future -> future.future().cancel(true));
}
}, "shutdown-hook");
LOGGER.log(System.Logger.Level.INFO, "Shutdown finished");
}, "nima-shutdown-hook");

Runtime.getRuntime().addShutdownHook(shutdownHook);
// we also need to keep the logging system active until the shutdown hook completes
// this introduces a hard dependency on JUL, as we cannot abstract this easily away
// this is to workaround https://bugs.openjdk.java.net/browse/JDK-8161253
keepLoggingActive(shutdownHook);
}

private void deregisterShutdownHook() {
Expand Down Expand Up @@ -255,6 +270,61 @@ private boolean parallel(String taskName, Consumer<ServerListener> task) {
return result;
}

private void keepLoggingActive(Thread shutdownHook) {
Logger rootLogger = LogManager.getLogManager().getLogger("");
Handler[] handlers = rootLogger.getHandlers();

List<Handler> newHandlers = new ArrayList<>();

boolean added = false;
for (Handler handler : handlers) {
if (handler instanceof KeepLoggingActiveHandler) {
// we want to replace it with our current shutdown hook
newHandlers.add(new KeepLoggingActiveHandler(shutdownHook));
added = true;
} else {
newHandlers.add(handler);
}
}
if (!added) {
// out handler must be first, so other handlers are not closed before we finish shutdown hook
newHandlers.add(0, new KeepLoggingActiveHandler(shutdownHook));
}

for (Handler handler : handlers) {
rootLogger.removeHandler(handler);
}
for (Handler newHandler : newHandlers) {
rootLogger.addHandler(newHandler);
}
}

private record ListenerFuture(ServerListener listener, Future<?> future) {
}

private static final class KeepLoggingActiveHandler extends Handler {
private final Thread shutdownHook;

private KeepLoggingActiveHandler(Thread shutdownHook) {
this.shutdownHook = shutdownHook;
}

@Override
public void publish(LogRecord record) {
// noop
}

@Override
public void flush() {
// noop
}

@Override
public void close() {
try {
shutdownHook.join();
} catch (InterruptedException ignored) {
}
}
}
}
2 changes: 2 additions & 0 deletions nima/webserver/webserver/src/main/java/module-info.java
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,8 @@
requires io.helidon.pico.builder.config;

requires java.management;
// only used to keep logging active until shutdown hook finishes
requires java.logging;

requires jakarta.annotation;
requires io.helidon.common.uri;
Expand Down

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