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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.logging.log4j.core.async;
import java.util.List;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.ThreadContext;
import org.apache.logging.log4j.ThreadContext.ContextStack;
import org.apache.logging.log4j.core.ContextDataInjector;
import org.apache.logging.log4j.core.Logger;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.LoggerConfig;
import org.apache.logging.log4j.core.config.Property;
import org.apache.logging.log4j.core.config.ReliabilityStrategy;
import org.apache.logging.log4j.core.impl.ContextDataFactory;
import org.apache.logging.log4j.core.impl.ContextDataInjectorFactory;
import org.apache.logging.log4j.core.util.Clock;
import org.apache.logging.log4j.core.util.ClockFactory;
import org.apache.logging.log4j.core.util.NanoClock;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.message.MessageFactory;
import org.apache.logging.log4j.message.ReusableMessage;
import org.apache.logging.log4j.spi.AbstractLogger;
import org.apache.logging.log4j.status.StatusLogger;
import org.apache.logging.log4j.util.StackLocatorUtil;
import org.apache.logging.log4j.util.StringMap;
import com.lmax.disruptor.EventTranslatorVararg;
import com.lmax.disruptor.dsl.Disruptor;
/**
* AsyncLogger is a logger designed for high throughput and low latency logging. It does not perform any I/O in the
* calling (application) thread, but instead hands off the work to another thread as soon as possible. The actual
* logging is performed in the background thread. It uses LMAX
* Disruptor for inter-thread communication.
*
* To use AsyncLogger, specify the System property
* {@code -DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector} before you obtain a
* Logger, and all Loggers returned by LogManager.getLogger will be AsyncLoggers.
*
* Note that for performance reasons, this logger does not include source location by default. You need to specify
* {@code includeLocation="true"} in the configuration or any %class, %location or %line conversion patterns in your
* log4j.xml configuration will produce either a "?" character or no output at all.
*
* For best performance, use AsyncLogger with the RandomAccessFileAppender or RollingRandomAccessFileAppender, with
* immediateFlush=false. These appenders have built-in support for the batching mechanism used by the Disruptor library,
* and they will flush to disk at the end of each batch. This means that even with immediateFlush=false, there will
* never be any items left in the buffer; all log events will all be written to disk in a very efficient manner.
*/
public class AsyncLogger extends Logger implements EventTranslatorVararg {
// Implementation note: many methods in this class are tuned for performance. MODIFY WITH CARE!
// Specifically, try to keep the hot methods to 35 bytecodes or less:
// this is within the MaxInlineSize threshold and makes these methods candidates for
// immediate inlining instead of waiting until they are designated "hot enough".
private static final StatusLogger LOGGER = StatusLogger.getLogger();
private static final Clock CLOCK = ClockFactory.getClock(); // not reconfigurable
private static final ContextDataInjector CONTEXT_DATA_INJECTOR = ContextDataInjectorFactory.createInjector();
private static final ThreadNameCachingStrategy THREAD_NAME_CACHING_STRATEGY = ThreadNameCachingStrategy.create();
private final ThreadLocal threadLocalTranslator = new ThreadLocal<>();
private final AsyncLoggerDisruptor loggerDisruptor;
private volatile boolean includeLocation; // reconfigurable
private volatile NanoClock nanoClock; // reconfigurable
/**
* Constructs an {@code AsyncLogger} with the specified context, name and message factory.
*
* @param context context of this logger
* @param name name of this logger
* @param messageFactory message factory of this logger
* @param loggerDisruptor helper class that logging can be delegated to. This object owns the Disruptor.
*/
public AsyncLogger(final LoggerContext context, final String name, final MessageFactory messageFactory,
final AsyncLoggerDisruptor loggerDisruptor) {
super(context, name, messageFactory);
this.loggerDisruptor = loggerDisruptor;
includeLocation = privateConfig.loggerConfig.isIncludeLocation();
nanoClock = context.getConfiguration().getNanoClock();
}
/*
* (non-Javadoc)
*
* @see org.apache.logging.log4j.core.Logger#updateConfiguration(org.apache.logging.log4j.core.config.Configuration)
*/
@Override
protected void updateConfiguration(final Configuration newConfig) {
nanoClock = newConfig.getNanoClock();
includeLocation = newConfig.getLoggerConfig(name).isIncludeLocation();
super.updateConfiguration(newConfig);
}
// package protected for unit tests
NanoClock getNanoClock() {
return nanoClock;
}
private RingBufferLogEventTranslator getCachedTranslator() {
RingBufferLogEventTranslator result = threadLocalTranslator.get();
if (result == null) {
result = new RingBufferLogEventTranslator();
threadLocalTranslator.set(result);
}
return result;
}
@Override
public void logMessage(final String fqcn, final Level level, final Marker marker, final Message message,
final Throwable thrown) {
getTranslatorType().log(fqcn, level, marker, message, thrown);
}
@Override
public void log(final Level level, final Marker marker, final String fqcn, final StackTraceElement location,
final Message message, final Throwable throwable) {
getTranslatorType().log(fqcn, location, level, marker, message, throwable);
}
abstract class TranslatorType {
abstract void log(final String fqcn, final StackTraceElement location, final Level level, final Marker marker,
final Message message, final Throwable thrown);
abstract void log(final String fqcn, final Level level, final Marker marker,
final Message message, final Throwable thrown);
}
private final TranslatorType threadLocalTranslatorType = new TranslatorType() {
@Override
void log(String fqcn, StackTraceElement location, Level level, Marker marker, Message message,
Throwable thrown) {
logWithThreadLocalTranslator(fqcn, location, level, marker, message, thrown);
}
@Override
void log(String fqcn, Level level, Marker marker, Message message, Throwable thrown) {
logWithThreadLocalTranslator(fqcn, level, marker, message, thrown);
}
};
private final TranslatorType varargTranslatorType = new TranslatorType() {
@Override
void log(String fqcn, StackTraceElement location, Level level, Marker marker, Message message,
Throwable thrown) {
logWithVarargTranslator(fqcn, location, level, marker, message, thrown);
}
@Override
void log(String fqcn, Level level, Marker marker, Message message, Throwable thrown) {
// LOG4J2-1172: avoid storing non-JDK classes in ThreadLocals to avoid memory leaks in web apps
logWithVarargTranslator(fqcn, level, marker, message, thrown);
}
};
private TranslatorType getTranslatorType() {
return loggerDisruptor.isUseThreadLocals() ? threadLocalTranslatorType : varargTranslatorType;
}
private boolean isReused(final Message message) {
return message instanceof ReusableMessage;
}
/**
* Enqueues the specified log event data for logging in a background thread.
*
* This re-uses a {@code RingBufferLogEventTranslator} instance cached in a {@code ThreadLocal} to avoid creating
* unnecessary objects with each event.
*
* @param fqcn fully qualified name of the caller
* @param level level at which the caller wants to log the message
* @param marker message marker
* @param message the log message
* @param thrown a {@code Throwable} or {@code null}
*/
private void logWithThreadLocalTranslator(final String fqcn, final Level level, final Marker marker,
final Message message, final Throwable thrown) {
// Implementation note: this method is tuned for performance. MODIFY WITH CARE!
final RingBufferLogEventTranslator translator = getCachedTranslator();
initTranslator(translator, fqcn, level, marker, message, thrown);
initTranslatorThreadValues(translator);
publish(translator);
}
/**
* Enqueues the specified log event data for logging in a background thread.
*
* This re-uses a {@code RingBufferLogEventTranslator} instance cached in a {@code ThreadLocal} to avoid creating
* unnecessary objects with each event.
*
* @param fqcn fully qualified name of the caller
* @param location the Location of the caller.
* @param level level at which the caller wants to log the message
* @param marker message marker
* @param message the log message
* @param thrown a {@code Throwable} or {@code null}
*/
private void logWithThreadLocalTranslator(final String fqcn, final StackTraceElement location, final Level level,
final Marker marker, final Message message, final Throwable thrown) {
// Implementation note: this method is tuned for performance. MODIFY WITH CARE!
final RingBufferLogEventTranslator translator = getCachedTranslator();
initTranslator(translator, fqcn, location, level, marker, message, thrown);
initTranslatorThreadValues(translator);
publish(translator);
}
private void publish(final RingBufferLogEventTranslator translator) {
if (!loggerDisruptor.tryPublish(translator)) {
handleRingBufferFull(translator);
}
}
private void handleRingBufferFull(final RingBufferLogEventTranslator translator) {
if (AbstractLogger.getRecursionDepth() > 1) { // LOG4J2-1518, LOG4J2-2031
// If queue is full AND we are in a recursive call, call appender directly to prevent deadlock
AsyncQueueFullMessageUtil.logWarningToStatusLogger();
logMessageInCurrentThread(translator.fqcn, translator.level, translator.marker, translator.message,
translator.thrown);
translator.clear();
return;
}
final EventRoute eventRoute = loggerDisruptor.getEventRoute(translator.level);
switch (eventRoute) {
case ENQUEUE:
loggerDisruptor.enqueueLogMessageWhenQueueFull(translator);
break;
case SYNCHRONOUS:
logMessageInCurrentThread(translator.fqcn, translator.level, translator.marker, translator.message,
translator.thrown);
translator.clear();
break;
case DISCARD:
translator.clear();
break;
default:
throw new IllegalStateException("Unknown EventRoute " + eventRoute);
}
}
private void initTranslator(final RingBufferLogEventTranslator translator, final String fqcn,
final StackTraceElement location, final Level level, final Marker marker,
final Message message, final Throwable thrown) {
translator.setBasicValues(this, name, marker, fqcn, level, message, //
// don't construct ThrowableProxy until required
thrown,
// needs shallow copy to be fast (LOG4J2-154)
ThreadContext.getImmutableStack(), //
location,
CLOCK, //
nanoClock //
);
}
private void initTranslator(final RingBufferLogEventTranslator translator, final String fqcn,
final Level level, final Marker marker, final Message message, final Throwable thrown) {
translator.setBasicValues(this, name, marker, fqcn, level, message, //
// don't construct ThrowableProxy until required
thrown,
// needs shallow copy to be fast (LOG4J2-154)
ThreadContext.getImmutableStack(), //
// location (expensive to calculate)
calcLocationIfRequested(fqcn), //
CLOCK, //
nanoClock //
);
}
private void initTranslatorThreadValues(final RingBufferLogEventTranslator translator) {
// constant check should be optimized out when using default (CACHED)
if (THREAD_NAME_CACHING_STRATEGY == ThreadNameCachingStrategy.UNCACHED) {
translator.updateThreadValues();
}
}
/**
* Returns the caller location if requested, {@code null} otherwise.
*
* @param fqcn fully qualified caller name.
* @return the caller location if requested, {@code null} otherwise.
*/
private StackTraceElement calcLocationIfRequested(final String fqcn) {
// location: very expensive operation. LOG4J2-153:
// Only include if "includeLocation=true" is specified,
// exclude if not specified or if "false" was specified.
return includeLocation ? StackLocatorUtil.calcLocation(fqcn) : null;
}
/**
* Enqueues the specified log event data for logging in a background thread.
*
* This creates a new varargs Object array for each invocation, but does not store any non-JDK classes in a
* {@code ThreadLocal} to avoid memory leaks in web applications (see LOG4J2-1172).
*
* @param fqcn fully qualified name of the caller
* @param level level at which the caller wants to log the message
* @param marker message marker
* @param message the log message
* @param thrown a {@code Throwable} or {@code null}
*/
private void logWithVarargTranslator(final String fqcn, final Level level, final Marker marker,
final Message message, final Throwable thrown) {
// Implementation note: candidate for optimization: exceeds 35 bytecodes.
final Disruptor disruptor = loggerDisruptor.getDisruptor();
if (disruptor == null) {
LOGGER.error("Ignoring log event after Log4j has been shut down.");
return;
}
// if the Message instance is reused, there is no point in freezing its message here
if (!isReused(message)) {
InternalAsyncUtil.makeMessageImmutable(message);
}
StackTraceElement location = null;
// calls the translateTo method on this AsyncLogger
if (!disruptor.getRingBuffer().tryPublishEvent(this,
this, // asyncLogger: 0
(location = calcLocationIfRequested(fqcn)), // location: 1
fqcn, // 2
level, // 3
marker, // 4
message, // 5
thrown)) { // 6
handleRingBufferFull(location, fqcn, level, marker, message, thrown);
}
}
/**
* Enqueues the specified log event data for logging in a background thread.
*
* This creates a new varargs Object array for each invocation, but does not store any non-JDK classes in a
* {@code ThreadLocal} to avoid memory leaks in web applications (see LOG4J2-1172).
*
* @param fqcn fully qualified name of the caller
* @param location location of the caller.
* @param level level at which the caller wants to log the message
* @param marker message marker
* @param message the log message
* @param thrown a {@code Throwable} or {@code null}
*/
private void logWithVarargTranslator(final String fqcn, final StackTraceElement location, final Level level,
final Marker marker, final Message message, final Throwable thrown) {
// Implementation note: candidate for optimization: exceeds 35 bytecodes.
final Disruptor disruptor = loggerDisruptor.getDisruptor();
if (disruptor == null) {
LOGGER.error("Ignoring log event after Log4j has been shut down.");
return;
}
// if the Message instance is reused, there is no point in freezing its message here
if (!isReused(message)) {
InternalAsyncUtil.makeMessageImmutable(message);
}
// calls the translateTo method on this AsyncLogger
if (!disruptor.getRingBuffer().tryPublishEvent(this,
this, // asyncLogger: 0
location, // location: 1
fqcn, // 2
level, // 3
marker, // 4
message, // 5
thrown)) { // 6
handleRingBufferFull(location, fqcn, level, marker, message, thrown);
}
}
/*
* (non-Javadoc)
*
* @see com.lmax.disruptor.EventTranslatorVararg#translateTo(java.lang.Object, long, java.lang.Object[])
*/
@Override
public void translateTo(final RingBufferLogEvent event, final long sequence, final Object... args) {
// Implementation note: candidate for optimization: exceeds 35 bytecodes.
final AsyncLogger asyncLogger = (AsyncLogger) args[0];
final StackTraceElement location = (StackTraceElement) args[1];
final String fqcn = (String) args[2];
final Level level = (Level) args[3];
final Marker marker = (Marker) args[4];
final Message message = (Message) args[5];
final Throwable thrown = (Throwable) args[6];
// needs shallow copy to be fast (LOG4J2-154)
final ContextStack contextStack = ThreadContext.getImmutableStack();
final Thread currentThread = Thread.currentThread();
final String threadName = THREAD_NAME_CACHING_STRATEGY.getThreadName();
event.setValues(asyncLogger, asyncLogger.getName(), marker, fqcn, level, message, thrown,
// config properties are taken care of in the EventHandler thread
// in the AsyncLogger#actualAsyncLog method
CONTEXT_DATA_INJECTOR.injectContextData(null, (StringMap) event.getContextData()),
contextStack, currentThread.getId(), threadName, currentThread.getPriority(), location,
CLOCK, nanoClock);
}
/**
* LOG4J2-471: prevent deadlock when RingBuffer is full and object being logged calls Logger.log() from its
* toString() method
*
* @param fqcn fully qualified caller name
* @param level log level
* @param marker optional marker
* @param message log message
* @param thrown optional exception
*/
void logMessageInCurrentThread(final String fqcn, final Level level, final Marker marker,
final Message message, final Throwable thrown) {
// bypass RingBuffer and invoke Appender directly
final ReliabilityStrategy strategy = privateConfig.loggerConfig.getReliabilityStrategy();
strategy.log(this, getName(), fqcn, marker, level, message, thrown);
}
private void handleRingBufferFull(final StackTraceElement location,
final String fqcn,
final Level level,
final Marker marker,
final Message msg,
final Throwable thrown) {
if (AbstractLogger.getRecursionDepth() > 1) { // LOG4J2-1518, LOG4J2-2031
// If queue is full AND we are in a recursive call, call appender directly to prevent deadlock
AsyncQueueFullMessageUtil.logWarningToStatusLogger();
logMessageInCurrentThread(fqcn, level, marker, msg, thrown);
return;
}
final EventRoute eventRoute = loggerDisruptor.getEventRoute(level);
switch (eventRoute) {
case ENQUEUE:
loggerDisruptor.enqueueLogMessageWhenQueueFull(this,
this, // asyncLogger: 0
location, // location: 1
fqcn, // 2
level, // 3
marker, // 4
msg, // 5
thrown); // 6
break;
case SYNCHRONOUS:
logMessageInCurrentThread(fqcn, level, marker, msg, thrown);
break;
case DISCARD:
break;
default:
throw new IllegalStateException("Unknown EventRoute " + eventRoute);
}
}
/**
* This method is called by the EventHandler that processes the RingBufferLogEvent in a separate thread.
* Merges the contents of the configuration map into the contextData, after replacing any variables in the property
* values with the StrSubstitutor-supplied actual values.
*
* @param event the event to log
*/
public void actualAsyncLog(final RingBufferLogEvent event) {
final LoggerConfig privateConfigLoggerConfig = privateConfig.loggerConfig;
final List properties = privateConfigLoggerConfig.getPropertyList();
if (properties != null) {
onPropertiesPresent(event, properties);
}
privateConfigLoggerConfig.getReliabilityStrategy().log(this, event);
}
@SuppressWarnings("ForLoopReplaceableByForEach") // Avoid iterator allocation
private void onPropertiesPresent(final RingBufferLogEvent event, final List properties) {
StringMap contextData = getContextData(event);
for (int i = 0, size = properties.size(); i < size; i++) {
final Property prop = properties.get(i);
if (contextData.getValue(prop.getName()) != null) {
continue; // contextMap overrides config properties
}
final String value = prop.isValueNeedsLookup() //
? privateConfig.config.getStrSubstitutor().replace(event, prop.getValue()) //
: prop.getValue();
contextData.putValue(prop.getName(), value);
}
event.setContextData(contextData);
}
private static StringMap getContextData(final RingBufferLogEvent event) {
StringMap contextData = (StringMap) event.getContextData();
if (contextData.isFrozen()) {
final StringMap temp = ContextDataFactory.createContextData();
temp.putAll(contextData);
return temp;
}
return contextData;
}
}