org.apache.kafka.common.utils.LoggingSignalHandler Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.common.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public class LoggingSignalHandler {
private static final Logger log = LoggerFactory.getLogger(LoggingSignalHandler.class);
private static final List SIGNALS = Arrays.asList("TERM", "INT", "HUP");
private final Constructor signalConstructor;
private final Class signalHandlerClass;
private final Class signalClass;
private final Method signalHandleMethod;
private final Method signalGetNameMethod;
private final Method signalHandlerHandleMethod;
/**
* Create an instance of this class.
*
* @throws ReflectiveOperationException if the underlying API has changed in an incompatible manner.
*/
public LoggingSignalHandler() throws ReflectiveOperationException {
signalClass = Class.forName("sun.misc.Signal");
signalConstructor = signalClass.getConstructor(String.class);
signalHandlerClass = Class.forName("sun.misc.SignalHandler");
signalHandlerHandleMethod = signalHandlerClass.getMethod("handle", signalClass);
signalHandleMethod = signalClass.getMethod("handle", signalClass, signalHandlerClass);
signalGetNameMethod = signalClass.getMethod("getName");
}
/**
* Register signal handler to log termination due to SIGTERM, SIGHUP and SIGINT (control-c). This method
* does not currently work on Windows.
*
* @implNote sun.misc.Signal and sun.misc.SignalHandler are described as "not encapsulated" in
* http://openjdk.java.net/jeps/260. However, they are not available in the compile classpath if the `--release`
* flag is used. As a workaround, we rely on reflection.
*/
public void register() throws ReflectiveOperationException {
Map jvmSignalHandlers = new ConcurrentHashMap<>();
for (String signal : SIGNALS) {
register(signal, jvmSignalHandlers);
}
log.info("Registered signal handlers for " + String.join(", ", SIGNALS));
}
private Object createSignalHandler(final Map jvmSignalHandlers) {
InvocationHandler invocationHandler = new InvocationHandler() {
private String getName(Object signal) throws Throwable {
try {
return (String) signalGetNameMethod.invoke(signal);
} catch (InvocationTargetException e) {
throw e.getCause();
}
}
private void handle(Object signalHandler, Object signal) throws ReflectiveOperationException {
signalHandlerHandleMethod.invoke(signalHandler, signal);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Object signal = args[0];
log.info("Terminating process due to signal {}", signal);
Object handler = jvmSignalHandlers.get(getName(signal));
if (handler != null)
handle(handler, signal);
return null;
}
};
return Proxy.newProxyInstance(Utils.getContextOrKafkaClassLoader(), new Class[] {signalHandlerClass},
invocationHandler);
}
private void register(String signalName, final Map jvmSignalHandlers) throws ReflectiveOperationException {
Object signal = signalConstructor.newInstance(signalName);
Object signalHandler = createSignalHandler(jvmSignalHandlers);
Object oldHandler = signalHandleMethod.invoke(null, signal, signalHandler);
if (oldHandler != null)
jvmSignalHandlers.put(signalName, oldHandler);
}
}