How to give environmental variable path for file appender in configuration file in log4j

log4j environment variable log level
log4j configuration file
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log4j2 not writing to file
log4j2 multiple appenders properties
log4j file appender

I have a log4j.xml config file. and a RollingFileAppender to which I need to provide file path for storing logs. The problem is my code will be deployed on Unix machine as a runnable jar. So if I pass parameter something like this:

value=logs/messages.log"

it creates folder named logs inside my HOME directory and writes all the messages to file inside this directory.

I have a environmental variable set to some value. I want to use path of that variable and write messages under that path. How can I achieve it?

I had tried using this:

value="${MY_HOME}/logs/message.log"

but this does not work. Can anyone suggest a solution for this problem?

When parsing its configuration file, the expression ${MY_HOME} will be expanded to the value of the system property named MY_HOME, not the system environment variable. There's a difference between the two.

To achieve this in a clean way, you'll have to add something like this to the JVM invocation line:

-DMY_HOME=$MY_HOME

That would define the Java system property MY_HOME to contain the value of the environment variable MY_HOME.

Log4j – Log4j 2 Lookups, Information on how to use Lookups in configuration files can be found The EnvironmentLookup allows systems to configure environment variables, either in global files In this example the RoutingAppender picks a route based on the respectively provide the absolute path to the log4j configuration file  I have a log4j.xml config file. and a RollingFileAppender to which I need to provide file path for storing logs. The problem is my code will be deployed on Unix machine as a runnable jar. So if I p

you CAN give it environment variables. Just preppend env: before the variable name, like this:

value="${env:MY_HOME}/logs/message.log"

Log4j – Configuring Log4j 2, It then defines a static logger variable with the name MyApp which happens to be the fully Log4j will provide a default configuration if it cannot locate a configuration file. SSS} [%t] %-5level %logger{36} - %msg%n" attached to the ConsoleAppender dest, Either "err" for stderr, "out" for stdout, a file path, or a URL. I have different logs locations in development and in production, they also may be different platforms, so I want to configure the logs just one time using a environment variable.

This syntax is documented only in log4j 2.X so make sure you are using the correct version.

    <Appenders>
    <File name="file" fileName="${env:LOG_PATH}">
        <PatternLayout>
            <Pattern>%d %p %c{1.} [%t] %m %ex%n</Pattern>
        </PatternLayout>
    </File>
</Appenders>

http://logging.apache.org/log4j/2.x/manual/lookups.html#EnvironmentLookup

Changing log4j through environment variables · Issue #5684 , Changing log4j through environment variables #5684 java -Dlog4j.​configuration=file:/path/to/custom/log4j.properties -jar metabase.jar. Seems you can use log4net.Util.PatternString to insert environment variables into the file path. So the OP's example becomes: Add type="log4net.Util.PatternString" to the file element and then specify the %env pattern specifier followed by the environment variable name in curly brackets.

I got this working.

  1. In my log4j.properties. I specified

log4j.appender.file.File=${LogFilePath}

  1. in eclipse - JVM arguments

-DLogFilePath=C:\work\MyLogFile.log

Using environment variable in log4j.properties, log4j.appender.app. allow java client to name log file via system property. System. 11/29/2004 12:59 Subject: Re: Using environment variable in log4j.​properties. PM and in your config file system properties are used to set variables To use Log4J 2 in your application, you need to ensure that the Log4J 2 jars are on your project classpath. If you intend to use the properties file, give extra attention to ensure that you have the Log4J 2.4 or greater jars on the classpath. Otherwise, your properties file will not get picked.

java -DLOG_DIR=${LOG_DIR} -jar myjar.jar "param1" "param2" ==> in cmd line if you have "value="${LOG_DIR}/log/clientProject/project-error.log" in xml

how to pass environment variable to log4j, If you want to use environment variables in log4j, for example, you want to control the log file java -Dserver.base=${SERVER_BASE} -Dlog4j.configuration=file:${​PARENT}/conf/log4j.xml . <appender name="SACCT" Is it possible to reference system environment variables (as opposed to Java system properties) in a log4j xml configuration file? I'd like to be able to do something like: <level value="${env.LOG_LEVEL}" /> and have it get that from the system environment variables, so I can avoid having to pass in so many things with -D parameters.

How to pass properties to the Log4j configuration file, For example, you have a File Appender, and the path to that log file depends on the Now, we need to pass the environment variable. There is  The entity should either extend org.apache.logging.log4j.core.appender.db.jpa.BasicLogEventEntity (if you mostly want to use the default mappings) and provide at least an @Id property, or org.apache.logging.log4j.core.appender.db.jpa.AbstractLogEventWrapperEntity (if you want to significantly customize the mappings). See the Javadoc for these

Logging with log4j, With the log4j.xml configuration file, you can do the following: SYSTEM "log4j.​dtd" > <log4j:configuration> <appender name="file" class="org.apache.log4j. This is set to the environment variable of $VIEWPOINT_HOME upon web application startup. The default path to the files that contain the logs are contained at  In this > different solution you would add a line like this to the properties > file: > > log4cplus.appender.ROLLFILE.File=${FILENAME} > > Then you would set the property's value in your code. > > props.setPropery (LOG4CPLUS_TEXT ("FILENAME"), file_path_string_here); > > Depending on the fShadowEnvironment flag absence or presence, it could > be or could not be overridden using same name environment variable. > >> >> I have not tested this but I think it should work this way. HTH.

environment variable in log4j xml config file? (Open Source Projects , I have just set up log4j logging on a web application that I have just started to work with. <appender name= "ConsoleAppender" class = "org.apache.log4j. variable in the configuration file rather than an absolut file path. The MaxBackupIndex tells the log4j to keep a maximum of 2 backup files for the log applog.log. If the log file is exceeding the MaximumFileSize, then the contents will be copied to a backup file and the logging will be added to a new empty applog.log file. From the above configuration, there can be a maximum of 2 backup files can be created.

Comments
  • I suspect that it's only using your home directory as the base because that's the current working directory of the Java process…
  • Thank you for the reply. Can you please tell me how to add the above statement to JVM invocation line.
  • You had mentioned that your code is deployed on a Unix machine, as a runnable JAR. Somewhere on your Unix machine there is a shell script (or something of the like) that invokes the JAR file (using java -jar myapp.jar, plus parameters); simply add -DMY_HOME=$MY_HOME to that line.
  • ohh ok. Thank you @Isaac for the help. So that means I dont require any changes in my XML file: Here is the code : <param name="File" value="${MY_HOME}/logs/Logfile.log"/>
  • Right. You won't require any changes in the code. (If you do it right...)
  • Put -DMY_HOME=$MY_HOME (don't forget the hyphen) in the VM Arguments section, not the Program arguments section.
  • This is the ultimate answer considering you are using Log4j2 and not the first version. Thank you!
  • Hi @vikingsteve, regarding "This is for log4j 2.X. Doesnt work for 1.2.17", even though I configured to use log 2.8.2, it still did not read from the environment variable, my shell script is a spark_submit job. below is my dependency: <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-core</artifactId> <version>2.8.2</version> In the end, I had to use system property approach.
  • Is this also working under Windows?
  • This will is the code for properties file. Will ${MY_HOME}/logs/message.log work with XML file as well. Because I had tried using similar stuff with XML file, but did not work.
  • This is for my configuration file. This will work, no issues with it. But what I want is to append the $MY_HOME path to the file appender path, which I am using for logging messages in my XML config file.
  • May I ask in this case, how I could pass "MY_HOME" variable into my Java Application. At moment, I have the following piece of code "System.out.println("System MY_HOME: " + System.getenv("MY_HOME"));" But it end up print out a "System MY_HOME: null" when I trying to pass "MY_HOME" from Eclipse -> Run Configuration -> Arguments -> Program arguments : -DMY_HOME=$MY_HOME
  • new Properties(String) doesn't even exist?! So what does that could help for?
  • But OP wants to use an environment variable to control the path.