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lovelock/DailyRollingWithMaxBackupIndexFileAppender.java

Last active September 21, 2023 01:07
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Daily rolling file appender for log4j with maxBackupIndex
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DailyRollingWithMaxBackupIndexFileAppender.java
package fun.happyhacker;
import org.apache.log4j.FileAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;
import java.io.File;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.ZoneOffset;
import java.util.*;
public class DailyRollingWithMaxBackupIndexFileAppender extends FileAppender {
// The code assumes that the following constants are in a increasing
// sequence.
static final int TOP_OF_TROUBLE = -1;
static final int TOP_OF_MINUTE = 0;
static final int TOP_OF_HOUR = 1;
static final int HALF_DAY = 2;
static final int TOP_OF_DAY = 3;
static final int TOP_OF_WEEK = 4;
static final int TOP_OF_MONTH = 5;
private int maxBackupIndex = 1;
/**
* The date pattern. By default, the pattern is set to
* "'.'yyyy-MM-dd" meaning daily rollover.
*/
private String datePattern = "'.'yyyy-MM-dd";
/**
* The log file will be renamed to the value of the
* scheduledFilename variable when the next interval is entered. For
* example, if the rollover period is one hour, the log file will be
* renamed to the value of "scheduledFilename" at the beginning of
* the next hour.
* <p>
* The precise time when a rollover occurs depends on logging
* activity.
*/
private String scheduledFilename;
/**
* The next time we estimate a rollover should occur.
*/
private long nextCheck = System.currentTimeMillis() - 1;
Date now = new Date();
SimpleDateFormat sdf;
RollingCalendar rc = new RollingCalendar();
int checkPeriod = TOP_OF_TROUBLE;
// The gmtTimeZone is used only in computeCheckPeriod() method.
static final TimeZone gmtTimeZone = TimeZone.getTimeZone("GMT");
/**
* The default constructor does nothing.
*/
public DailyRollingWithMaxBackupIndexFileAppender() {
}
/**
* Instantiate a <code>DailyRollingFileAppender</code> and open the
* file designated by <code>filename</code>. The opened filename will
* become the ouput destination for this appender.
*/
public DailyRollingWithMaxBackupIndexFileAppender(Layout layout, String filename,
String datePattern) throws IOException {
super(layout, filename, true);
this.datePattern = datePattern;
activateOptions();
}
/**
* The <b>DatePattern</b> takes a string in the same format as
* expected by {@link SimpleDateFormat}. This options determines the
* rollover schedule.
*/
public void setDatePattern(String pattern) {
datePattern = pattern;
}
/**
* Returns the value of the <b>DatePattern</b> option.
*/
public String getDatePattern() {
return datePattern;
}
public void setMaxBackupIndex(int maxBackupIndex) {
this.maxBackupIndex = maxBackupIndex;
}
public int getMaxBackupIndex() {
return this.maxBackupIndex;
}
public void activateOptions() {
super.activateOptions();
if (datePattern != null && fileName != null) {
now.setTime(System.currentTimeMillis());
sdf = new SimpleDateFormat(datePattern);
int type = computeCheckPeriod();
printPeriodicity(type);
rc.setType(type);
File file = new File(fileName);
scheduledFilename = fileName + sdf.format(new Date(file.lastModified()));
} else {
LogLog.error("Either File or DatePattern options are not set for appender ["
+ name + "].");
}
}
void printPeriodicity(int type) {
switch (type) {
case TOP_OF_MINUTE:
LogLog.debug("Appender [" + name + "] to be rolled every minute.");
break;
case TOP_OF_HOUR:
LogLog.debug("Appender [" + name
+ "] to be rolled on top of every hour.");
break;
case HALF_DAY:
LogLog.debug("Appender [" + name
+ "] to be rolled at midday and midnight.");
break;
case TOP_OF_DAY:
LogLog.debug("Appender [" + name
+ "] to be rolled at midnight.");
break;
case TOP_OF_WEEK:
LogLog.debug("Appender [" + name
+ "] to be rolled at start of week.");
break;
case TOP_OF_MONTH:
LogLog.debug("Appender [" + name
+ "] to be rolled at start of every month.");
break;
default:
LogLog.warn("Unknown periodicity for appender [" + name + "].");
}
}
// This method computes the roll over period by looping over the
// periods, starting with the shortest, and stopping when the r0 is
// different from from r1, where r0 is the epoch formatted according
// the datePattern (supplied by the user) and r1 is the
// epoch+nextMillis(i) formatted according to datePattern. All date
// formatting is done in GMT and not local format because the test
// logic is based on comparisons relative to 1970-01-01 00:00:00
// GMT (the epoch).
int computeCheckPeriod() {
RollingCalendar rollingCalendar = new RollingCalendar(gmtTimeZone, Locale.getDefault());
// set sate to 1970-01-01 00:00:00 GMT
Date epoch = new Date(0);
if (datePattern != null) {
for (int i = TOP_OF_MINUTE; i <= TOP_OF_MONTH; i++) {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat(datePattern);
simpleDateFormat.setTimeZone(gmtTimeZone); // do all date formatting in GMT
String r0 = simpleDateFormat.format(epoch);
rollingCalendar.setType(i);
Date next = new Date(rollingCalendar.getNextCheckMillis(epoch));
String r1 = simpleDateFormat.format(next);
//System.out.println("Type = "+i+", r0 = "+r0+", r1 = "+r1);
if (r0 != null && r1 != null && !r0.equals(r1)) {
return i;
}
}
}
return TOP_OF_TROUBLE; // Deliberately head for trouble...
}
/**
* Rollover the current file to a new file.
*/
void rollOver() throws IOException {
/* Compute filename, but only if datePattern is specified */
if (datePattern == null) {
errorHandler.error("Missing DatePattern option in rollOver().");
return;
}
String datedFilename = fileName + sdf.format(now);
// It is too early to roll over because we are still within the
// bounds of the current interval. Rollover will occur once the
// next interval is reached.
if (scheduledFilename.equals(datedFilename)) {
return;
}
// close current file, and rename it to datedFilename
this.closeFile();
long boundary = LocalDate.now().minusDays(maxBackupIndex).atStartOfDay().toEpochSecond(ZoneOffset.of("+8")) * 1000;
File target = new File(scheduledFilename);
File logDir = new File(target.getParent());
if (logDir.isDirectory()) {
File[] logs = logDir.listFiles();
if (logs != null) {
for (File log : logs) {
if (log.getAbsolutePath().startsWith(fileName)) {
String suffix = log.getAbsolutePath().substring(fileName.length());
try {
long epochSecond = sdf.parse(suffix).getTime();
if (epochSecond < boundary) {
log.delete();
}
} catch (ParseException e) {
LogLog.debug("log filename " + log.getAbsolutePath() + " is not formal");
}
}
}
}
}
if (target.exists()) {
target.delete();
}
File file = new File(fileName);
boolean result = file.renameTo(target);
if (result) {
LogLog.debug(fileName + " -> " + scheduledFilename);
} else {
LogLog.error("Failed to rename [" + fileName + "] to [" + scheduledFilename + "].");
}
try {
// This will also close the file. This is OK since multiple
// close operations are safe.
this.setFile(fileName, true, this.bufferedIO, this.bufferSize);
} catch (IOException e) {
errorHandler.error("setFile(" + fileName + ", true) call failed.");
}
scheduledFilename = datedFilename;
}
/**
* This method differentiates DailyRollingFileAppender from its
* super class.
*
* <p>Before actually logging, this method will check whether it is
* time to do a rollover. If it is, it will schedule the next
* rollover time and then rollover.
*/
protected void subAppend(LoggingEvent event) {
long n = System.currentTimeMillis();
if (n >= nextCheck) {
now.setTime(n);
nextCheck = rc.getNextCheckMillis(now);
try {
rollOver();
} catch (IOException ioe) {
if (ioe instanceof InterruptedIOException) {
Thread.currentThread().interrupt();
}
LogLog.error("rollOver() failed.", ioe);
}
}
super.subAppend(event);
}
}
/**
* RollingCalendar is a helper class to DailyRollingFileAppender.
* Given a periodicity type and the current time, it computes the
* start of the next interval.
*/
class RollingCalendar extends GregorianCalendar {
private static final long serialVersionUID = -3560331770601814177L;
int type = DailyRollingWithMaxBackupIndexFileAppender.TOP_OF_TROUBLE;
RollingCalendar() {
super();
}
RollingCalendar(TimeZone tz, Locale locale) {
super(tz, locale);
}
void setType(int type) {
this.type = type;
}
public long getNextCheckMillis(Date now) {
return getNextCheckDate(now).getTime();
}
public Date getNextCheckDate(Date now) {
this.setTime(now);
switch (type) {
case DailyRollingWithMaxBackupIndexFileAppender.TOP_OF_MINUTE:
this.set(Calendar.SECOND, 0);
this.set(Calendar.MILLISECOND, 0);
this.add(Calendar.MINUTE, 1);
break;
case DailyRollingWithMaxBackupIndexFileAppender.TOP_OF_HOUR:
this.set(Calendar.MINUTE, 0);
this.set(Calendar.SECOND, 0);
this.set(Calendar.MILLISECOND, 0);
this.add(Calendar.HOUR_OF_DAY, 1);
break;
case DailyRollingWithMaxBackupIndexFileAppender.HALF_DAY:
this.set(Calendar.MINUTE, 0);
this.set(Calendar.SECOND, 0);
this.set(Calendar.MILLISECOND, 0);
int hour = get(Calendar.HOUR_OF_DAY);
if (hour < 12) {
this.set(Calendar.HOUR_OF_DAY, 12);
} else {
this.set(Calendar.HOUR_OF_DAY, 0);
this.add(Calendar.DAY_OF_MONTH, 1);
}
break;
case DailyRollingWithMaxBackupIndexFileAppender.TOP_OF_DAY:
this.set(Calendar.HOUR_OF_DAY, 0);
this.set(Calendar.MINUTE, 0);
this.set(Calendar.SECOND, 0);
this.set(Calendar.MILLISECOND, 0);
this.add(Calendar.DATE, 1);
break;
case DailyRollingWithMaxBackupIndexFileAppender.TOP_OF_WEEK:
this.set(Calendar.DAY_OF_WEEK, getFirstDayOfWeek());
this.set(Calendar.HOUR_OF_DAY, 0);
this.set(Calendar.MINUTE, 0);
this.set(Calendar.SECOND, 0);
this.set(Calendar.MILLISECOND, 0);
this.add(Calendar.WEEK_OF_YEAR, 1);
break;
case DailyRollingWithMaxBackupIndexFileAppender.TOP_OF_MONTH:
this.set(Calendar.DATE, 1);
this.set(Calendar.HOUR_OF_DAY, 0);
this.set(Calendar.MINUTE, 0);
this.set(Calendar.SECOND, 0);
this.set(Calendar.MILLISECOND, 0);
this.add(Calendar.MONTH, 1);
break;
default:
throw new IllegalStateException("Unknown periodicity type.");
}
return getTime();
}
}
Raw
log4j.properties
log4j.rootLogger=debug,CONSOLE,RFA
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.Target=System.out
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
log4j.appender.RFA=fun.happyhacker.DailyRollingWithMaxBackupIndexFileAppender
log4j.appender.RFA.Threshold=DEBUG
log4j.appender.RFA.File=/tmp/logs/app.log
log4j.appender.RFA.Append=true
log4j.appender.RFA.maxBackupIndex=2
log4j.appender.RFA.DatePattern=-yyyy-MM-dd
log4j.appender.RFA.layout=org.apache.log4j.PatternLayout
log4j.appender.RFA.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} %-5p %-60c %x - %m%n
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