Develop Reference

log4j2 Dynamic log file name in Java

I have simple question.
How to have log file name dynamically supplied from code?
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="warn" name="MyApp" packages="">
<Appenders>
<RollingFile name="RollingFile" fileName="${logfilename}.log"
filePattern="logs/$${date:yyyy-MM}/app-%d{yyyy-MM-dd-HH}-%i.log.gz">
<PatternLayout>
<Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
</PatternLayout>
<Policies>
<TimeBasedTriggeringPolicy interval="6" modulate="true"/>
<SizeBasedTriggeringPolicy size="250 MB"/>
</Policies>
</RollingFile>
</Appenders>
<Loggers>
<Root level="error">
<AppenderRef ref="RollingFile"/>
</Root>
</Loggers>
Here file name is logs/app.log.
How to make it dynamic with date and time appended as well in file name? Though pattern is applied but it doesn't work.
Here logs is the directory which log4j library automatically creates, can it be dynamic as well?
EDIT In parameter fileName I have placed ${logfilename}.log and setting system property as below:
System.setProperty("logfilename", "a_cool_logname");
Now it is creating file with name ${logfilename}.log which is definitely not required.
Thanks

**Property File Look like this **
log4j.rootLogger=DEBUG, FA
#Console Appender WE WRE NOT USING IT
log4j.appender.CA=org.apache.log4j.ConsoleAppender
log4j.appender.CA.layout=org.apache.log4j.PatternLayout
log4j.appender.CA.layout.ConversionPattern=%d{dd MM yy HH:mm} %-5p %m%n
#File Appender
log4j.appender.FA=org.apache.log4j.FileAppender
log4j.appender.FA.File=${fName}
#log4j.appender.FA.MaxFileSize=5MB
#log4j.appender.FA.MaxBackupIndex=3
log4j.appender.FA.layout=org.apache.log4j.PatternLayout
log4j.appender.FA.layout.ConversionPattern=%d{dd MM yy HH:mm} %8p %10m%n
# Set the logger level of File Appender to WARN
log4j.appender.FA.Threshold = INFO
log4j.appender.FA.Threshold = DEBUG
**And set Properties in JAVA **
System.setProperty("fName", "d:\\siemens\\" + getDateTime() + c.getSimpleName() +".log");
PropertyConfigurator.configure("log4j.properties");
let me know if u need further query thanks

log4j 2 RollingFile not rolling over

We have WAR deployments running on Tomcat containers which are using log4j 2.5 for logging events. We have now amended the deployments' log4j2.xml configuration to have the log files roll over every 24 hours but, with this new configuration, the rollover of files are not taking place as we would expect.
Sample configuration:
<RollingFile name="file"
fileName="${sys:catalina.base}/logs/${web:contextPath}.log"
filePattern="${sys:catalina.base}/logs/${web:contextPath}-%d{dd-MMM-yyyy}.log"
append="true">
<PatternLayout pattern="%d{dd-MMM-yyyy HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" >
<header>LOG START DATE=${date:dd-MMM-yyyy HH:mm:ss.SSS} APP=${web:contextPath} TOMCAT=${env:HOSTNAME}:${env:CONNECTOR_PORT}${sys:line.separator}</header>
<footer>LOG END DATE=${date:dd-MMM-yyyy HH:mm:ss.SSS} APP=${web:contextPath} TOMCAT=${env:HOSTNAME}:${env:CONNECTOR_PORT}${sys:line.separator}</footer>
</PatternLayout>
<Policies>
<TimeBasedTriggeringPolicy/>
</Policies>
</RollingFile>
Any ideas why the rollover is not taking place?
NOTE: The same configuration but with a <CronTriggeringPolicy schedule="0 0 0 * * ?" /> instead of TimeBasedTriggeringPolicy does rollover but, in this case, the rolled over files get created with today's date in the filename and NOT yesterday's date.
NOTE2: We have other deployments with similar configuration that do rollover every 24 hours but those configurations have the filename hardcoded instead of using ${web:contextPath}. Could this lookup have something to do with why RollingFile might not work?
--- EDIT ---
UPDATE: We are able to get TimeBasedTriggeringPolicy to rollover files using above configuration when the Tomcat instance is running on Windows but NOT when the Tomcat instance is running on Linux.

There is nothing wrong with your configuration snippet as I get the desired behaviour of time based rolling.
To test, I changed the dd-MMM-yyyy to dd-MMM-yyyy-HH-mm and my log file rolls every minute.
It must be something else that is preventing you from achieving the desired behaviour.
My setup #1:
Log4j2 v2.8.2
Apache Tomcat 8.5.13
Windows 7 Enterprise SP1
My setup #2:
Log4j2 v2.5
Apache Tomcat 7.0.77
CentOS 7 (1611)
I have the following 3 JARs in WEB-INF/lib:
log4j-api-2.5.jar
log4j-core-2.5.jar
log4j-web-2.5.jar
Here is my complete log4j2.xml for your reference:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="DEBUG">
<Appenders>
<RollingFile name="RollingFileAppender"
fileName="${sys:catalina.base}/logs/${web:contextPath}.log"
filePattern="${sys:catalina.base}/logs/${web:contextPath}-%d{dd-MMM-yyyy-HH-mm}.log"
append="true">
<PatternLayout pattern="%d{dd-MMM-yyyy HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" >
<header>LOG START DATE=${date:dd-MMM-yyyy HH:mm:ss.SSS} APP=${web:contextPath} TOMCAT=${env:HOSTNAME}:${env:CONNECTOR_PORT}${sys:line.separator}</header>
<footer>LOG END DATE=${date:dd-MMM-yyyy HH:mm:ss.SSS} APP=${web:contextPath} TOMCAT=${env:HOSTNAME}:${env:CONNECTOR_PORT}${sys:line.separator}</footer>
</PatternLayout>
<Policies>
<TimeBasedTriggeringPolicy/>
</Policies>
</RollingFile>
</Appenders>
<Loggers>
<Logger name="root" level="debug" additivity="false">
<appender-ref ref="RollingFileAppender" level="debug"/>
</Logger>
<Root level="debug" additivity="false">
<AppenderRef ref="RollingFileAppender"/>
</Root>
</Loggers>
</Configuration>

Log4j2: file logging not working with jar

I have a java application with log4j2 configured in order to log to console and to file.
When i start my application from ecplise, all the log are ok (console and file).
When i start the jar of the application from CMD or Powershell (as admin), only the console log works.
If i start the jar by only double click, the file log works (but no console is displayed).
This my log4j2.xml configuration:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO">
<Appenders>
<File name="file_all" fileName="logs/ALL.log">
<PatternLayout>
<Pattern>%d{yyyy-MM-dd HH:mm:ss} [%t] %-5level %logger{36} - %msg%n</Pattern>
</PatternLayout>
</File>
<File name="file_error" fileName="logs/ERROR.log">
<PatternLayout>
<Pattern>%d{yyyy-MM-dd HH:mm:ss} [%t] %-5level %logger{36} - %msg%n</Pattern>
</PatternLayout>
</File>
<Console name="STDOUT" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
</Appenders>
<Loggers>
<Root level="trace">
<AppenderRef ref="file_all" level="INFO"/>
<AppenderRef ref="file_error" level="ERROR"/>
<AppenderRef ref="STDOUT" level="INFO"/>
</Root>
</Loggers>
</Configuration>

Your log4j2.xml config file starts with <configuration status="off" ... (or perhaps WARN or ERROR, you haven't shown the full config).
To investigate, switch on log4j's internal status logging by changing this to <configuration status="trace" ...
This will show output on the console. (You can redirect this to a file with java -jar myjar.jar > out.log.)
I hope this will give us more info on what is going on. Please paste that output into your question.
EDIT: the status output looks good; no errors or anything. Could it be that double-clicking a jar file is associated with javaw (not java), so there is no console? You mention that when starting the application from a CMD prompt or Powershell, you cannot find the log file. The line "Starting FileManager logs/ALL.log" in the status log tells me that log4j2 successfully created an output stream. However, this is a relative path, and the status log does not mention the absolute path. I think it is relative to the current directory, so what is the current directory of the CMD prompt or Powershell?

How to configure Log4J2

I have spent a couple hours now trying to figure this out and am at a complete loss. I find the new configuration process unnecessarily complex.
I have a Servlet with a web.xml file with the following:
<context-param>
<param-name>log4jConfiguration</param-name>
<param-value>file:///etc/myApp/log4j2.xml</param-value>
</context-param>
It doesn't seem to have any effect. I am using Tomcat 7.0.42, and I have removed all references to log4j*.jar in the catalina.properties file. The logs in my app are still being sent, but they are just being sent to System.out with none of the formatting I specified.
So, I tried to just do it by hand on my own:
InputStream in =
new FileInputStream(new File("/etc/myApp/log4j2.xml"));
ConfigurationSource source = new ConfigurationSource(in);
ConfigurationFactory factory = new XMLConfigurationFactory();
Configuration configuration = factory.getConfiguration(source);
LoggerContext context = (LoggerContext) LogManager.getContext();
context.start(configuration);
context.updateLoggers();
Logger.getLogger("Test").log(Level.INFO, "This is a logging message.");
First, this seems entirely convoluted. Clearly there exists some code that will search for different files and assume file types based on their extensions via the "log4jConfiguration" property, so why isn't there a LogManger.reconfigure(String) that has the same effect?
Second, this has no effect either. Again, the log is printed to System.out, and none of the requested formatting is being done.
Here is the contents of my log4j2.xml:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="DEBUG">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
<File name="LogFile" fileName="/var/log/myApp/myApp.log">
<PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %p %c{1.} [%t] %m%n"/>
</File>
</Appenders>
<Loggers>
<Root level="DEBUG">
<AppenderRef ref="Console" level="DEBUG"/>
<AppenderRef ref="LogFile" level="DEBUG"/>
</Root>
</Loggers>
</Configuration>
The output in both cases comes out something like:
Dec 03, 2013 6:06:45 PM test.Test main
INFO: This is a logging message.
Thanks in advance,
John
EDIT: This is actually working. It appears that I was missing, "log4j-jcl-2.0-beta9.jar". Remko Popma's answer works as well, if the "context-param" above is not working.

There are many possible scenarios with webapp logging, which makes configuration more complex than the ideal. Putting the log4j2 jars and the config file in your webapp's classpath should work. Did you see the manual page for log4j2 use in web apps? If the issue remains, please file a log4j2 jira ticket.

The LoggerContextalready has a method setConfigLocation that takes in a URI as parameter. It baffles me why there isn't a similar method that takes an InputStream as parameter. Instead we have to deal with the most convoluted and messy way of loading our log4j2.xml that is not on the classpath.

log4j2 monthly log rollover

I'm using Log4J 2.0 to create logs for a project that I'm doing. The logs are small and I have a requirement to maintain them for 3 months. I'd like to have the current month's log with 3 archives (each containing a month's worth of logs).
The problem that I need help with is configuring log4j to rotate the logs at the beginning of the month (or the end of the month).
Pretty much every thing that I've found researching this problem is for log4j 1.x and talks about a datePattern parameter that doesn't appear to exist in 2.0.
Here's my log4j2.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<configuration status="warn" name="NKMS" packages="">
<appenders>
<FastRollingFile name="LogFile" fileName="logs/Tier2HttpServer.log" filePattern="logs/app-%d{yyyy-MM-dd}.log.gz">
<ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>
<PatternLayout pattern="%d %p %c{1.} [%t] %m%n"/>
<Policies>
<TimeBasedTriggeringPolicy/>
<SizeBasedTriggeringPolicy size="250 MB"/>
</Policies>
<DefaultRolloverStrategy max="4"/>
</FastRollingFile>
<Console name="STDOUT" target="SYSTEM_OUT">
<PatternLayout pattern="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
</Console>
</appenders>
<loggers>
<logger name="mil.navy.nrl.itd.xml_filter" level="trace"/>
<root level="trace">
<appender-ref ref="STDOUT"/>
<appender-ref ref="LogFile"/>
</root>
</loggers>
</configuration>
I'm writing INFO and above to the log file and debug to the console (for now). The files are written to just fine, but they appear to rollover daily (which appears to be the default).
I've tried changing the FastRollingFile:filePattern to "'.'yyyy-MM" but that causes weird things to happen (only a single entry is written to file and an archive is immediately created).
I downloaded the source for log4j-2.0-beta8 and the PatternProcessor parses a RolloverFrequency that contains the enum RolloverFrequency.MONTHLY, but there again, I can't figure out how to implement / use it.
As always, any assistance or advice that you can provide would be GREATLY APPRECIATED!
-Ace

You may have found a bug. I would expect the filePattern of "logs/app-%d{yyyy-MM}.log.gz" to give you what you're looking for.
To clarify my understanding of the problem: The initial log event immediately triggers a rollover (creating an archive file). Instead, it should collect log events into the log file and not roll over until the end/beginning of the month. Is that description correct? Is there any other issue in addition to this initial unnecessary rollover?
Could I ask you to raise a JIRA ticket for this? https://issues.apache.org/jira/browse/LOG4J2