org.apache.logging.log4j.core.LoggerContext Maven / Gradle / Ivy
/*
* 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;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;
import java.net.URI;
import java.util.Collection;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.ConfigurationFactory;
import org.apache.logging.log4j.core.config.ConfigurationListener;
import org.apache.logging.log4j.core.config.ConfigurationSource; // SUPPRESS CHECKSTYLE
import org.apache.logging.log4j.core.config.DefaultConfiguration;
import org.apache.logging.log4j.core.config.NullConfiguration;
import org.apache.logging.log4j.core.config.Reconfigurable;
import org.apache.logging.log4j.core.impl.Log4jLogEvent;
import org.apache.logging.log4j.core.jmx.Server;
import org.apache.logging.log4j.core.util.Cancellable;
import org.apache.logging.log4j.core.util.NanoClockFactory;
import org.apache.logging.log4j.core.util.NetUtils;
import org.apache.logging.log4j.core.util.ShutdownCallbackRegistry;
import org.apache.logging.log4j.message.MessageFactory;
import org.apache.logging.log4j.spi.AbstractLogger;
import org.apache.logging.log4j.spi.LoggerContextFactory;
import org.apache.logging.log4j.spi.LoggerContextKey;
import static org.apache.logging.log4j.core.util.ShutdownCallbackRegistry.*;
/**
* The LoggerContext is the anchor for the logging system. It maintains a list of all the loggers requested by
* applications and a reference to the Configuration. The Configuration will contain the configured loggers, appenders,
* filters, etc and will be atomically updated whenever a reconfigure occurs.
*/
public class LoggerContext extends AbstractLifeCycle implements org.apache.logging.log4j.spi.LoggerContext,
ConfigurationListener {
/**
* Property name of the property change event fired if the configuration is changed.
*/
public static final String PROPERTY_CONFIG = "config";
private static final long serialVersionUID = 1L;
private static final Configuration NULL_CONFIGURATION = new NullConfiguration();
private final ConcurrentMap loggers = new ConcurrentHashMap<>();
private final CopyOnWriteArrayList propertyChangeListeners = new CopyOnWriteArrayList<>();
/**
* The Configuration is volatile to guarantee that initialization of the Configuration has completed before the
* reference is updated.
*/
private volatile Configuration configuration = new DefaultConfiguration();
private Object externalContext;
private String contextName;
private volatile URI configLocation;
private Cancellable shutdownCallback;
private final Lock configLock = new ReentrantLock();
/**
* Constructor taking only a name.
*
* @param name The context name.
*/
public LoggerContext(final String name) {
this(name, null, (URI) null);
}
/**
* Constructor taking a name and a reference to an external context.
*
* @param name The context name.
* @param externalContext The external context.
*/
public LoggerContext(final String name, final Object externalContext) {
this(name, externalContext, (URI) null);
}
/**
* Constructor taking a name, external context and a configuration URI.
*
* @param name The context name.
* @param externalContext The external context.
* @param configLocn The location of the configuration as a URI.
*/
public LoggerContext(final String name, final Object externalContext, final URI configLocn) {
this.contextName = name;
this.externalContext = externalContext;
this.configLocation = configLocn;
}
/**
* Constructor taking a name external context and a configuration location String. The location must be resolvable
* to a File.
*
* @param name The configuration location.
* @param externalContext The external context.
* @param configLocn The configuration location.
*/
public LoggerContext(final String name, final Object externalContext, final String configLocn) {
this.contextName = name;
this.externalContext = externalContext;
if (configLocn != null) {
URI uri;
try {
uri = new File(configLocn).toURI();
} catch (final Exception ex) {
uri = null;
}
configLocation = uri;
} else {
configLocation = null;
}
}
/**
* Returns the current LoggerContext.
*
* Avoids the type cast for:
*
*
*
* (LoggerContext) LogManager.getContext();
*
*
*
* WARNING - The LoggerContext returned by this method may not be the LoggerContext used to create a Logger for the
* calling class.
*
*
* @return The current LoggerContext.
* @see LogManager#getContext()
*/
public static LoggerContext getContext() {
return (LoggerContext) LogManager.getContext();
}
/**
* Returns a LoggerContext.
*
* Avoids the type cast for:
*
*
*
* (LoggerContext) LogManager.getContext(currentContext);
*
*
* @param currentContext if false the LoggerContext appropriate for the caller of this method is returned. For
* example, in a web application if the caller is a class in WEB-INF/lib then one LoggerContext may be
* returned and if the caller is a class in the container's classpath then a different LoggerContext may
* be returned. If true then only a single LoggerContext will be returned.
* @return a LoggerContext.
* @see LogManager#getContext(boolean)
*/
public static LoggerContext getContext(final boolean currentContext) {
return (LoggerContext) LogManager.getContext(currentContext);
}
/**
* Returns a LoggerContext.
*
* Avoids the type cast for:
*
*
*
* (LoggerContext) LogManager.getContext(loader, currentContext, configLocation);
*
*
* @param loader The ClassLoader for the context. If null the context will attempt to determine the appropriate
* ClassLoader.
* @param currentContext if false the LoggerContext appropriate for the caller of this method is returned. For
* example, in a web application if the caller is a class in WEB-INF/lib then one LoggerContext may be
* returned and if the caller is a class in the container's classpath then a different LoggerContext may
* be returned. If true then only a single LoggerContext will be returned.
* @param configLocation The URI for the configuration to use.
* @return a LoggerContext.
* @see LogManager#getContext(ClassLoader, boolean, URI)
*/
public static LoggerContext getContext(final ClassLoader loader, final boolean currentContext,
final URI configLocation) {
return (LoggerContext) LogManager.getContext(loader, currentContext, configLocation);
}
@Override
public void start() {
LOGGER.debug("Starting LoggerContext[name={}, {}]...", getName(), this);
if (configLock.tryLock()) {
try {
if (this.isInitialized() || this.isStopped()) {
this.setStarting();
reconfigure();
if (this.configuration.isShutdownHookEnabled()) {
setUpShutdownHook();
}
this.setStarted();
}
} finally {
configLock.unlock();
}
}
LOGGER.debug("LoggerContext[name={}, {}] started OK.", getName(), this);
}
/**
* Starts with a specific configuration.
*
* @param config The new Configuration.
*/
public void start(final Configuration config) {
LOGGER.debug("Starting LoggerContext[name={}, {}] with configuration {}...", getName(), this, config);
if (configLock.tryLock()) {
try {
if (this.isInitialized() || this.isStopped()) {
if (this.configuration.isShutdownHookEnabled()) {
setUpShutdownHook();
}
this.setStarted();
}
} finally {
configLock.unlock();
}
}
setConfiguration(config);
LOGGER.debug("LoggerContext[name={}, {}] started OK with configuration {}.", getName(), this, config);
}
private void setUpShutdownHook() {
if (shutdownCallback == null) {
final LoggerContextFactory factory = LogManager.getFactory();
if (factory instanceof ShutdownCallbackRegistry) {
LOGGER.debug(SHUTDOWN_HOOK_MARKER, "Shutdown hook enabled. Registering a new one.");
try {
this.shutdownCallback = ((ShutdownCallbackRegistry) factory).addShutdownCallback(new Runnable() {
@Override
public void run() {
final LoggerContext context = LoggerContext.this;
LOGGER.debug(SHUTDOWN_HOOK_MARKER, "Stopping LoggerContext[name={}, {}]",
context.getName(), context);
context.stop();
}
@Override
public String toString() {
return "Shutdown callback for LoggerContext[name=" + LoggerContext.this.getName() + ']';
}
});
} catch (final IllegalStateException e) {
LOGGER.error(SHUTDOWN_HOOK_MARKER,
"Unable to register shutdown hook because JVM is shutting down.", e);
} catch (final SecurityException e) {
LOGGER.error(SHUTDOWN_HOOK_MARKER, "Unable to register shutdown hook due to security restrictions",
e);
}
}
}
}
@Override
public void stop() {
LOGGER.debug("Stopping LoggerContext[name={}, {}]...", getName(), this);
configLock.lock();
try {
if (this.isStopped()) {
return;
}
this.setStopping();
try {
Server.unregisterLoggerContext(getName()); // LOG4J2-406, LOG4J2-500
} catch (final Exception ex) {
LOGGER.error("Unable to unregister MBeans", ex);
}
if (shutdownCallback != null) {
shutdownCallback.cancel();
shutdownCallback = null;
}
final Configuration prev = configuration;
configuration = NULL_CONFIGURATION;
updateLoggers();
prev.stop();
externalContext = null;
LogManager.getFactory().removeContext(this);
this.setStopped();
} finally {
configLock.unlock();
}
LOGGER.debug("Stopped LoggerContext[name={}, {}]...", getName(), this);
}
/**
* Gets the name.
*
* @return the name.
*/
public String getName() {
return contextName;
}
/**
* Gets the root logger.
*
* @return the root logger.
*/
public Logger getRootLogger() {
return getLogger(LogManager.ROOT_LOGGER_NAME);
}
/**
* Sets the name.
*
* @param name the new LoggerContext name
* @throws NullPointerException if the specified name is {@code null}
*/
public void setName(final String name) {
contextName = Objects.requireNonNull(name);
}
/**
* Sets the external context.
*
* @param context The external context.
*/
public void setExternalContext(final Object context) {
this.externalContext = context;
}
/**
* Returns the external context.
*
* @return The external context.
*/
@Override
public Object getExternalContext() {
return this.externalContext;
}
/**
* Gets a Logger from the Context.
*
* @param name The name of the Logger to return.
* @return The Logger.
*/
@Override
public Logger getLogger(final String name) {
return getLogger(name, null);
}
/**
* Gets a collection of the current loggers.
*
* Whether this collection is a copy of the underlying collection or not is undefined. Therefore, modify this
* collection at your own risk.
*
*
* @return a collection of the current loggers.
*/
public Collection getLoggers() {
return loggers.values();
}
/**
* Obtains a Logger from the Context.
*
* @param name The name of the Logger to return.
* @param messageFactory The message factory is used only when creating a logger, subsequent use does not change the
* logger but will log a warning if mismatched.
* @return The Logger.
*/
@Override
public Logger getLogger(final String name, final MessageFactory messageFactory) {
// Note: This is the only method where we add entries to the 'loggers' ivar.
// The loggers map key is the logger name plus the messageFactory FQCN.
String key = LoggerContextKey.create(name, messageFactory);
Logger logger = loggers.get(key);
if (logger != null) {
AbstractLogger.checkMessageFactory(logger, messageFactory);
return logger;
}
logger = newInstance(this, name, messageFactory);
// If messageFactory was null then we need to pull it out of the logger now
key = LoggerContextKey.create(name, logger.getMessageFactory());
final Logger prev = loggers.putIfAbsent(key, logger);
return prev == null ? logger : prev;
}
/**
* Determines if the specified Logger exists.
*
* @param name The Logger name to search for.
* @return True if the Logger exists, false otherwise.
*/
@Override
public boolean hasLogger(final String name) {
return loggers.containsKey(LoggerContextKey.create(name));
}
/**
* Determines if the specified Logger exists.
*
* @param name The Logger name to search for.
* @return True if the Logger exists, false otherwise.
*/
@Override
public boolean hasLogger(final String name, MessageFactory messageFactory) {
return loggers.containsKey(LoggerContextKey.create(name, messageFactory));
}
/**
* Determines if the specified Logger exists.
*
* @param name The Logger name to search for.
* @return True if the Logger exists, false otherwise.
*/
@Override
public boolean hasLogger(final String name, Class messageFactoryClass) {
return loggers.containsKey(LoggerContextKey.create(name, messageFactoryClass));
}
/**
* Returns the current Configuration. The Configuration will be replaced when a reconfigure occurs.
*
* @return The Configuration.
*/
public Configuration getConfiguration() {
return configuration;
}
/**
* Adds a Filter to the Configuration. Filters that are added through the API will be lost when a reconfigure
* occurs.
*
* @param filter The Filter to add.
*/
public void addFilter(final Filter filter) {
configuration.addFilter(filter);
}
/**
* Removes a Filter from the current Configuration.
*
* @param filter The Filter to remove.
*/
public void removeFilter(final Filter filter) {
configuration.removeFilter(filter);
}
/**
* Sets the Configuration to be used.
*
* @param config The new Configuration.
* @return The previous Configuration.
*/
private Configuration setConfiguration(final Configuration config) {
Objects.requireNonNull(config, "No Configuration was provided");
configLock.lock();
try {
final Configuration prev = this.configuration;
config.addListener(this);
final ConcurrentMap map = config.getComponent(Configuration.CONTEXT_PROPERTIES);
try { // LOG4J2-719 network access may throw android.os.NetworkOnMainThreadException
map.putIfAbsent("hostName", NetUtils.getLocalHostname());
} catch (final Exception ex) {
LOGGER.debug("Ignoring {}, setting hostName to 'unknown'", ex.toString());
map.putIfAbsent("hostName", "unknown");
}
map.putIfAbsent("contextName", contextName);
config.start();
this.configuration = config;
updateLoggers();
if (prev != null) {
prev.removeListener(this);
prev.stop();
}
firePropertyChangeEvent(new PropertyChangeEvent(this, PROPERTY_CONFIG, prev, config));
try {
Server.reregisterMBeansAfterReconfigure();
} catch (final Throwable t) {
// LOG4J2-716: Android has no java.lang.management
LOGGER.error("Could not reconfigure JMX", t);
}
// AsyncLoggers update their nanoClock when the configuration changes
Log4jLogEvent.setNanoClock(NanoClockFactory.createNanoClock());
return prev;
} finally {
configLock.unlock();
}
}
private void firePropertyChangeEvent(final PropertyChangeEvent event) {
for (final PropertyChangeListener listener : propertyChangeListeners) {
listener.propertyChange(event);
}
}
public void addPropertyChangeListener(final PropertyChangeListener listener) {
propertyChangeListeners.add(Objects.requireNonNull(listener, "listener"));
}
public void removePropertyChangeListener(final PropertyChangeListener listener) {
propertyChangeListeners.remove(listener);
}
/**
* Returns the initial configuration location or {@code null}. The returned value may not be the location of the
* current configuration. Use {@link #getConfiguration()}.{@link Configuration#getConfigurationSource()
* getConfigurationSource()}.{@link ConfigurationSource#getLocation() getLocation()} to get the actual source of the
* current configuration.
*
* @return the initial configuration location or {@code null}
*/
public URI getConfigLocation() {
return configLocation;
}
/**
* Sets the configLocation to the specified value and reconfigures this context.
*
* @param configLocation the location of the new configuration
*/
public void setConfigLocation(final URI configLocation) {
this.configLocation = configLocation;
reconfigure(configLocation);
}
/**
* Reconfigures the context.
*/
private void reconfigure(final URI configURI) {
final ClassLoader cl = ClassLoader.class.isInstance(externalContext) ? (ClassLoader) externalContext : null;
LOGGER.debug("Reconfiguration started for context[name={}] at URI {} ({}) with optional ClassLoader: {}",
contextName, configURI, this, cl);
final Configuration instance = ConfigurationFactory.getInstance().getConfiguration(contextName, configURI, cl);
setConfiguration(instance);
/*
* instance.start(); Configuration old = setConfiguration(instance); updateLoggers(); if (old != null) {
* old.stop(); }
*/
final String location = configuration == null ? "?" : String.valueOf(configuration.getConfigurationSource());
LOGGER.debug("Reconfiguration complete for context[name={}] at URI {} ({}) with optional ClassLoader: {}",
contextName, location, this, cl);
}
/**
* Reconfigures the context. Log4j does not remove Loggers during a reconfiguration. Log4j will create new
* LoggerConfig objects and Log4j will point the Loggers at the new LoggerConfigs. Log4j will free the old
* LoggerConfig, along with old Appenders and Filters.
*/
public void reconfigure() {
reconfigure(configLocation);
}
/**
* Causes all Loggers to be updated against the current Configuration.
*/
public void updateLoggers() {
updateLoggers(this.configuration);
}
/**
* Causes all Logger to be updated against the specified Configuration.
*
* @param config The Configuration.
*/
public void updateLoggers(final Configuration config) {
for (final Logger logger : loggers.values()) {
logger.updateConfiguration(config);
}
}
/**
* Causes a reconfiguration to take place when the underlying configuration file changes.
*
* @param reconfigurable The Configuration that can be reconfigured.
*/
@Override
public synchronized void onChange(final Reconfigurable reconfigurable) {
LOGGER.debug("Reconfiguration started for context {} ({})", contextName, this);
final Configuration newConfig = reconfigurable.reconfigure();
if (newConfig != null) {
setConfiguration(newConfig);
LOGGER.debug("Reconfiguration completed for {} ({})", contextName, this);
} else {
LOGGER.debug("Reconfiguration failed for {} ({})", contextName, this);
}
}
// LOG4J2-151: changed visibility from private to protected
protected Logger newInstance(final LoggerContext ctx, final String name, final MessageFactory messageFactory) {
return new Logger(ctx, name, messageFactory);
}
}