I am new to SLF4j and I don't know if the logback.xml file has loaded properly or not. The logback.xml file is in PROJECTNAME/src/main/java where all my packages are found.
My questions are:
How can I know if the configuration file has properly loaded or not
?
How can restrict the logging only from an explicit set of class,
only to avoid logging from libraries
You can add the debug="true" attribute to the <configuration> element to enable debug of the logback configuration. It will print the configuration to the console. See https://logback.qos.ch/manual/configuration.html#dumpingStatusData.
Simple answer, if the configuration file is loaded properly, you will see results in log file or console, depending on your configuration.
By default, logback searches file in src/main/resources instead of src/main/java if I remember correctly.
In the configuration file, you can define log lever on a specific logger. Normally you'll still want to see logs of the libraries, but maybe only WARN or ERROR, so you could set the root level to WARN/ERROR, and add a logger of your root package with DEBUG/INFO level.
Also, use a logback-test file (under src/test/resources) for your own dev environment.
Related
the log file is generated when I run the code within IDE (Intellij IDEA).
as soon as I create runnable jar of the code and then try to run the jar then the logs are not generating.
I have made sure the log4j2.xml file is a part of classpath.
is there anything extra I have to do while creating jar in the Intellij IDEA?
Taken from the FAQ: How do I debug my configuration?
First, make sure you have the right jar files on your classpath. You need at least log4j-api and log4j-core.
Next, check the name of your configuration file. By default, log4j2 will look for a configuration file named log4j2.xml on the classpath. Note the “2” in the file name! (See the configuration manual page for more details.)
From log4j-2.9 onward
From log4j-2.9 onward, log4j2 will print all internal logging to the console if system property log4j2.debug is either defined empty or its value equals to true (ignoring case).
Prior to log4j-2.9
Prior to log4j-2.9, there are two places where internal logging can be controlled:
If the configuration file is found correctly, log4j2 internal status logging can be controlled by setting in the configuration file. This will display detailed log4j2-internal log statements on the console about what happens during the configuration process. This may be useful to trouble-shoot configuration issues. By default the status logger level is WARN, so you only see notifications when there is a problem.
If the configuration file is not found correctly, you can still enable log4j2 internal status logging by setting system property -Dorg.apache.logging.log4j.simplelog.StatusLogger.level=TRACE.
I'm using LogBack with Slf4j.
At program startup LogBack searches the configuration file from various places and in case of finding nothing, it configures itself automatically by using BasicConfigurator.
http://logback.qos.ch/manual/configuration.html
At program startup I need to print out the used LogBack configuration file name.
How can I programmatically get the name/path of the loaded LogBack xml configuration file or some information if LogBack did not find any configuration file and configured itself automatically?
Would it be enough to set debug=true on logback.xml files? If not, following seems to work at least with logback 1.1.5 version but will create a direct dependency to logback:
LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();
System.out
.println(ConfigurationWatchListUtil.getConfigurationWatchList(context).getCopyOfFileWatchList().get(0));
I am using log4j for logger purpose. At the same time I am also using JXL to read/write Excel file.
But instead of writing log into log4j logger file, it is writing into jxl.log file.
What can be issue?
Looks like you have been using jxl-2.6.3.jar or similar version.
Log4j picks up the first configuration file with default file name ( i.e. log4j.xml or log4j.properties ) in your classpath if you haven't specified a specific name via JVM parameters. As jxl-2.6.3.jar contains a log4j.xml you ended up printing everything to jxl.log as defined in the log4j.xml
The best way to deal with these kind of problems is to run your application with -Dlog4j.debug JVM parameter. This would print a few line snippet when the log4j is initialized.
log4j: Using URL [jar:file:/C:/YourApp/WEB-INF/lib/jxl-2.6.3.jar!/log4j.xml] for automatic log4j configuration.
log4j: Preferred configurator class: org.apache.log4j.xml.DOMConfigurator
...{Blah Blah Blah}
There are many ways in which you can solve this problem.
Use the newer versions of jxl which doesn't contain log4j.xml.
Make sure your log4j.properties file is on top of classpath.
Remove the log4j.xml from the jxl-2.6.3.jar (Dirty solution).
Pass the configuration file name in VM parameter as -Dlog4j.configuration=log4j.properties. This would atleast make sure log4j.xml inside jxl-2.6.3.jar will not be used. (But what if another jar with same name as log4j.properties?).
Rename your log4j.properties file to log4j-yourApp.properties and add VM parameter -Dlog4j.configuration=log4j-yourApp.properties This would definitely help and this is how it should be done to avoid these kind of situations.
More details on Log4j here
I have a few Maven dependencies in my Java project that clutter the console output with redundant log info. I want to disable such logging.
Setting the additivity property to false might help. But could not use it properly.
I am looking for a log4j.xml config that will only print log output (warn, error, ...) from my project and not from any dependencies.
Redirect all the third party lib logs in a target appender, use another appender for your app
log4j.rootLogger=debug,thirdPartyLibAppender
log4j.logger.com.yourapp=debug, yourAppAppender
log4j.additivity.com.yourapp=false
# define where do you want third party lib logs to land : in a file
log4j.appender.thirdPartyLibAppender=org.apache.log4j.FileAppender
log4j.appender.thirdPartyLibAppender.append=true
log4j.appender.thirdPartyLibAppender.file=/tmp/app.log
log4j.appender.thirdPartyLibAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.thirdPartyLibAppender.layout.ConversionPattern=[%p] %c:%m%n
# define where do you want your app logs to land : stdout
log4j.appender.yourAppAppender=org.apache.log4j.ConsoleAppender
log4j.appender.yourAppAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.yourAppAppender.layout.ConversionPattern=[%p] %c:%m%n
Setting additivity to false will prevent that your app logs end in the thirdPartyLibAppender
In those 2 lines, don't forget to replace com.yourapp by the top level package name
log4j.logger.com.yourapp=debug, yourAppAppender
log4j.additivity.com.yourapp=false
It looks like the log4j2.xml was overriding all other configs. As of now, I have switched that dependency off. Maybe log4j2 > log4j hence the issue. Also, XML gets a higher priority over properties as I have seen somewhere.
I have a project which is in turn used by several other projects. I want log4j to log only my logs to a file that I have specified in the properties file. Other project use their own logging mechanisms and I have no control over them. My log4j files should not affect other project's logging. How should i configure my log4j property file?
So far what I'm doing is setting log4j.rootLogger = ERROR and for my module log4j.logger.com.xyz.myproject = INFO, FILE. Will this work without affecting other project's loggers? Or possibly limit logging to only my jar?
Thanks
It depends on the package structure of the other projects. Supposing that
loggers from other projects are created by Logger.getLogger(ClassA.class) AND
some of them rely on root logger configuration (have no specific log4j.category.loggerName settings AND
these projects contain subpackages of the package used by your project (i.e. your project's package is com.abc.def and other projects have packages deeper in the hierarchy com.abc.def.ghi THEN
changing com.abc.def logging level would affect other projects - they'll start logging on the level defined by com.abc.def.
Verify that it's not the case and you should be safe.
I suppose your jar is entirely contained in your own package (ex com.foo.mypackage). In this case, is just enough to add to your log4j configuration something like:
# Print only messages of priority WARN or above in the package com.foo
log4j.category.com.foo=WARN
# Print only messages of priority DEBUG or above in the package com.foo.mypackage
log4j.category.com.foo.mypackage=DEBUG
Regards,
M.