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The Apache Log4j Implementation
/*
* 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.appender.rolling;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;
import java.util.concurrent.TimeUnit;
import java.util.zip.Deflater;
import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.appender.rolling.action.Action;
import org.apache.logging.log4j.core.appender.rolling.action.FileRenameAction;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.lookup.StrSubstitutor;
import org.apache.logging.log4j.core.util.Integers;
/**
* When rolling over, DefaultRolloverStrategy renames files according to an algorithm as described below.
*
*
* The DefaultRolloverStrategy is a combination of a time-based policy and a fixed-window policy. When the file name
* pattern contains a date format then the rollover time interval will be used to calculate the time to use in the file
* pattern. When the file pattern contains an integer replacement token one of the counting techniques will be used.
*
*
* When the ascending attribute is set to true (the default) then the counter will be incremented and the current log
* file will be renamed to include the counter value. If the counter hits the maximum value then the oldest file, which
* will have the smallest counter, will be deleted, all other files will be renamed to have their counter decremented
* and then the current file will be renamed to have the maximum counter value. Note that with this counting strategy
* specifying a large maximum value may entirely avoid renaming files.
*
*
* When the ascending attribute is false, then the "normal" fixed-window strategy will be used.
*
*
* Let max and min represent the values of respectively the MaxIndex and MinIndex
* options. Let "foo.log" be the value of the ActiveFile option and "foo.%i.log" the value of
* FileNamePattern. Then, when rolling over, the file foo.max.log will be deleted, the file
* foo.max-1.log will be renamed as foo.max.log, the file
* foo.max-2.log renamed as foo.max-1.log, and so on, the file
* foo.min+1.log renamed as foo.min+2.log. Lastly, the active file
* foo.log will be renamed as foo.min.log and a new active file name
* foo.log will be created.
*
*
* Given that this rollover algorithm requires as many file renaming operations as the window size, large window sizes
* are discouraged.
*
*/
@Plugin(name = "DefaultRolloverStrategy", category = Core.CATEGORY_NAME, printObject = true)
public class DefaultRolloverStrategy extends AbstractRolloverStrategy {
private static final int MIN_WINDOW_SIZE = 1;
private static final int DEFAULT_WINDOW_SIZE = 7;
/**
* Creates the DefaultRolloverStrategy.
*
* @param max The maximum number of files to keep.
* @param min The minimum number of files to keep.
* @param fileIndex If set to "max" (the default), files with a higher index will be newer than files with a smaller
* index. If set to "min", file renaming and the counter will follow the Fixed Window strategy.
* @param compressionLevelStr The compression level, 0 (less) through 9 (more); applies only to ZIP files.
* @param customActions custom actions to perform asynchronously after rollover
* @param stopCustomActionsOnError whether to stop executing asynchronous actions if an error occurs
* @param config The Configuration.
* @return A DefaultRolloverStrategy.
*/
@PluginFactory
public static DefaultRolloverStrategy createStrategy(
// @formatter:off
@PluginAttribute("max") final String max,
@PluginAttribute("min") final String min,
@PluginAttribute("fileIndex") final String fileIndex,
@PluginAttribute("compressionLevel") final String compressionLevelStr,
@PluginElement("Actions") final Action[] customActions,
@PluginAttribute(value = "stopCustomActionsOnError", defaultBoolean = true)
final boolean stopCustomActionsOnError,
@PluginConfiguration final Configuration config) {
// @formatter:on
int minIndex;
int maxIndex;
boolean useMax;
if (fileIndex != null && fileIndex.equalsIgnoreCase("nomax")) {
minIndex = Integer.MIN_VALUE;
maxIndex = Integer.MAX_VALUE;
useMax = false;
} else {
useMax = fileIndex == null ? true : fileIndex.equalsIgnoreCase("max");
minIndex = MIN_WINDOW_SIZE;
if (min != null) {
minIndex = Integer.parseInt(min);
if (minIndex < 1) {
LOGGER.error("Minimum window size too small. Limited to " + MIN_WINDOW_SIZE);
minIndex = MIN_WINDOW_SIZE;
}
}
maxIndex = DEFAULT_WINDOW_SIZE;
if (max != null) {
maxIndex = Integer.parseInt(max);
if (maxIndex < minIndex) {
maxIndex = minIndex < DEFAULT_WINDOW_SIZE ? DEFAULT_WINDOW_SIZE : minIndex;
LOGGER.error("Maximum window size must be greater than the minimum windows size. Set to " + maxIndex);
}
}
}
final int compressionLevel = Integers.parseInt(compressionLevelStr, Deflater.DEFAULT_COMPRESSION);
return new DefaultRolloverStrategy(minIndex, maxIndex, useMax, compressionLevel, config.getStrSubstitutor(),
customActions, stopCustomActionsOnError);
}
/**
* Index for oldest retained log file.
*/
private final int maxIndex;
/**
* Index for most recent log file.
*/
private final int minIndex;
private final boolean useMax;
private final int compressionLevel;
private final List customActions;
private final boolean stopCustomActionsOnError;
/**
* Constructs a new instance.
*
* @param minIndex The minimum index.
* @param maxIndex The maximum index.
* @param customActions custom actions to perform asynchronously after rollover
* @param stopCustomActionsOnError whether to stop executing asynchronous actions if an error occurs
*/
protected DefaultRolloverStrategy(final int minIndex, final int maxIndex, final boolean useMax,
final int compressionLevel, final StrSubstitutor strSubstitutor, final Action[] customActions,
final boolean stopCustomActionsOnError) {
super(strSubstitutor);
this.minIndex = minIndex;
this.maxIndex = maxIndex;
this.useMax = useMax;
this.compressionLevel = compressionLevel;
this.stopCustomActionsOnError = stopCustomActionsOnError;
this.customActions = customActions == null ? Collections. emptyList() : Arrays.asList(customActions);
}
public int getCompressionLevel() {
return this.compressionLevel;
}
public List getCustomActions() {
return customActions;
}
public int getMaxIndex() {
return this.maxIndex;
}
public int getMinIndex() {
return this.minIndex;
}
public boolean isStopCustomActionsOnError() {
return stopCustomActionsOnError;
}
public boolean isUseMax() {
return useMax;
}
private int purge(final int lowIndex, final int highIndex, final RollingFileManager manager) {
return useMax ? purgeAscending(lowIndex, highIndex, manager) : purgeDescending(lowIndex, highIndex, manager);
}
/**
* Purges and renames old log files in preparation for rollover. The oldest file will have the smallest index, the
* newest the highest.
*
* @param lowIndex low index. Log file associated with low index will be deleted if needed.
* @param highIndex high index.
* @param manager The RollingFileManager
* @return true if purge was successful and rollover should be attempted.
*/
private int purgeAscending(final int lowIndex, final int highIndex, final RollingFileManager manager) {
final SortedMap eligibleFiles = getEligibleFiles(manager);
final int maxFiles = highIndex - lowIndex + 1;
boolean renameFiles = false;
while (eligibleFiles.size() >= maxFiles) {
try {
LOGGER.debug("Eligible files: {}", eligibleFiles);
Integer key = eligibleFiles.firstKey();
LOGGER.debug("Deleting {}", eligibleFiles.get(key).toFile().getAbsolutePath());
Files.delete(eligibleFiles.get(key));
eligibleFiles.remove(key);
renameFiles = true;
} catch (IOException ioe) {
LOGGER.error("Unable to delete {}, {}", eligibleFiles.firstKey(), ioe.getMessage(), ioe);
break;
}
}
final StringBuilder buf = new StringBuilder();
if (renameFiles) {
for (Map.Entry entry : eligibleFiles.entrySet()) {
buf.setLength(0);
// LOG4J2-531: directory scan & rollover must use same format
manager.getPatternProcessor().formatFileName(strSubstitutor, buf, entry.getKey() - 1);
String currentName = entry.getValue().toFile().getName();
String renameTo = buf.toString();
int suffixLength = suffixLength(renameTo);
if (suffixLength > 0 && suffixLength(currentName) == 0) {
renameTo = renameTo.substring(0, renameTo.length() - suffixLength);
}
Action action = new FileRenameAction(entry.getValue().toFile(), new File(renameTo), true);
try {
LOGGER.debug("DefaultRolloverStrategy.purgeAscending executing {}", action);
if (!action.execute()) {
return -1;
}
} catch (final Exception ex) {
LOGGER.warn("Exception during purge in RollingFileAppender", ex);
return -1;
}
}
}
return eligibleFiles.size() > 0 ?
(eligibleFiles.lastKey() < highIndex ? eligibleFiles.lastKey() + 1 : highIndex) : lowIndex;
}
/**
* Purges and renames old log files in preparation for rollover. The newest file will have the smallest index, the
* oldest will have the highest.
*
* @param lowIndex low index
* @param highIndex high index. Log file associated with high index will be deleted if needed.
* @param manager The RollingFileManager
* @return true if purge was successful and rollover should be attempted.
*/
private int purgeDescending(final int lowIndex, final int highIndex, final RollingFileManager manager) {
// Retrieve the files in descending order, so the highest key will be first.
final SortedMap eligibleFiles = getEligibleFiles(manager, false);
final int maxFiles = highIndex - lowIndex + 1;
while (eligibleFiles.size() >= maxFiles) {
try {
Integer key = eligibleFiles.firstKey();
Files.delete(eligibleFiles.get(key));
eligibleFiles.remove(key);
} catch (IOException ioe) {
LOGGER.error("Unable to delete {}, {}", eligibleFiles.firstKey(), ioe.getMessage(), ioe);
break;
}
}
final StringBuilder buf = new StringBuilder();
for (Map.Entry entry : eligibleFiles.entrySet()) {
buf.setLength(0);
// LOG4J2-531: directory scan & rollover must use same format
manager.getPatternProcessor().formatFileName(strSubstitutor, buf, entry.getKey() + 1);
String currentName = entry.getValue().toFile().getName();
String renameTo = buf.toString();
int suffixLength = suffixLength(renameTo);
if (suffixLength > 0 && suffixLength(currentName) == 0) {
renameTo = renameTo.substring(0, renameTo.length() - suffixLength);
}
Action action = new FileRenameAction(entry.getValue().toFile(), new File(renameTo), true);
try {
LOGGER.debug("DefaultRolloverStrategy.purgeDescending executing {}", action);
if (!action.execute()) {
return -1;
}
} catch (final Exception ex) {
LOGGER.warn("Exception during purge in RollingFileAppender", ex);
return -1;
}
}
return lowIndex;
}
/**
* Performs the rollover.
*
* @param manager The RollingFileManager name for current active log file.
* @return A RolloverDescription.
* @throws SecurityException if an error occurs.
*/
@Override
public RolloverDescription rollover(final RollingFileManager manager) throws SecurityException {
int fileIndex;
if (minIndex == Integer.MIN_VALUE) {
final SortedMap eligibleFiles = getEligibleFiles(manager);
fileIndex = eligibleFiles.size() > 0 ? eligibleFiles.lastKey() + 1 : 1;
} else {
if (maxIndex < 0) {
return null;
}
final long startNanos = System.nanoTime();
fileIndex = purge(minIndex, maxIndex, manager);
if (fileIndex < 0) {
return null;
}
if (LOGGER.isTraceEnabled()) {
final double durationMillis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos);
LOGGER.trace("DefaultRolloverStrategy.purge() took {} milliseconds", durationMillis);
}
}
final StringBuilder buf = new StringBuilder(255);
manager.getPatternProcessor().formatFileName(strSubstitutor, buf, fileIndex);
final String currentFileName = manager.getFileName();
String renameTo = buf.toString();
final String compressedName = renameTo;
Action compressAction = null;
FileExtension fileExtension = manager.getFileExtension();
if (fileExtension != null) {
renameTo = renameTo.substring(0, renameTo.length() - fileExtension.length());
compressAction = fileExtension.createCompressAction(renameTo, compressedName,
true, compressionLevel);
}
if (currentFileName.equals(renameTo)) {
LOGGER.warn("Attempt to rename file {} to itself will be ignored", currentFileName);
return new RolloverDescriptionImpl(currentFileName, false, null, null);
}
final FileRenameAction renameAction = new FileRenameAction(new File(currentFileName), new File(renameTo),
manager.isRenameEmptyFiles());
final Action asyncAction = merge(compressAction, customActions, stopCustomActionsOnError);
return new RolloverDescriptionImpl(currentFileName, false, renameAction, asyncAction);
}
@Override
public String toString() {
return "DefaultRolloverStrategy(min=" + minIndex + ", max=" + maxIndex + ", useMax=" + useMax + ")";
}
}