Using system environment variables in log4j xml configuration

log4j environment variable
system environment variables log4j
log4j logging variables
log4j2 jvm argument
log4j properties variable substitution
log4j configuration
log4j xml define variable
log4j.configurationfile system property

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.

This syntax is documented only in log4j 2.X so make sure you are using the correct version. It does not work on the 1.X versions.

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

How to give environmental variable path for file appender in , When parsing its configuration file, the expression ${MY_HOME} will be expanded to the value of the system property named MY_HOME , not the system environment variable. There's a infoFile.File=${MY_HOME}/logs/message.log log4j.appender. Since you are using unix you can use a path like this. 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.

I tried to do that recently and couldn't get it to work. What I ended up doing is sending a variable at startup. So say you have an environment variable called $LOG_LEVEL:

<level value="${log_level}" />

and at startup...

java -Dlog_level=$LOG_LEVEL your_app

using variables in log4j xml file, wondering if it is possible to use environment variables in the config sets some system properties and that is probably what you are seeing referenced Log4j 2.x has much richer support for properties in configuration file, see the Log4j manual about Configuration with properties. Log4j 1.x (the original answer): The only way to achieve something similar when you are using log4j.xml is to set a system property at startup and then reference that from your log4j.xml. At startup, you set your system property: java -Dlog_dir =/ var / logs / custom com. yourorg. yourapp. Main

I think this is not supported, but basically you can do two things to bring in your environment variables:

  1. Use System.setProperty before Log4J gets configured

  2. Convert (your) environment variables to system properties in your launcher

The first option basically boils down to this:

for (Map<String,String>.Entry entry : System.getenv().entrySet()) {
  System.setProperty(entry.getKey(), entry.getValue());
}

... but the question is of course where to put this code. In particular if you're running within some sort of Tomcat container or similar, this might be troublesome.

The other largely depends on your environment. Basically if you have a shell script that starts your app, you can write some shell magic to set all environment variables as properties, or just the ones you need, e.g.:

java -DMY_ENV=$MY_ENV -DMY_OTHER_ENV=$MY_OTHER_ENV -cp ... com.example.Main

It's also possible to alter your server startup scripts to support this, e.g. catalina.sh or similar.

Log4j – Log4j 2 Lookups, Information on how to use Lookups in configuration files can be found in the Property The EnvironmentLookup allows systems to configure environment variables, either in for applications, and then retrieve those variables from within the logging configuration. <?xml version="1.0" encoding="UTF-8"?>  It looks like you did everything right. I don't think there is any difference between setting the property inside your main class with System.setProperty() and specifying it via the command line as long as it happens befor actual log4j initialization. I think your issue is that your logging framework gets loaded before you specify the property. I can say that the logging framework (log4j) will get configured when you call the configurator.

You need to put a colon between env and the name of the variable, like this:

<level value="${env:LOG_LEVEL}" />

environment variable in log4j xml config file? (Open Source Projects , Question. 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  LoggerContext is a vocal point for Logging system as you may have multiple LoggerContexts inside your application. Per each LoggerContext an active configuration should be set. Log4j2 configuration contains all Logging system assets; LoggerConfig (s), Appender (s), Filter (s) and many others.

Create a system variable. I prefer to use setenv.bat for such variables.

@echo off
rem app specific log dir
set "APP_LOG_ROOTDIR=../app/app-log"
exit /b 0

Add reference in log4j.xml file

<appender name="fileAppender" class="org.apache.log4j.RollingFileAppender">
  <param name="Threshold" value="DEBUG" />
  <param name="MaxFileSize" value="512KB" />
  <param name="MaxBackupIndex" value="10" />
  <param name="File" value="${APP_LOG_ROOTDIR}/app.log"/>
  <layout class="org.apache.log4j.PatternLayout">
   <param name="ConversionPattern" value="%d %-5p %c{1} %m %n" />
  </layout>
</appender>

how to pass environment variable to log4j, 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  The two most common configuration options are in practice i.e. using log4j.xml configuration or using log4j.properties configuration. In this log4j xml configuration tutorial, I am showing the example code for log4j.xml configuration. Read more: Log4j properties file example. 1. Log4j maven dependencies

How to pass properties to the Log4j configuration file, DOCTYPE log4j:configuration SYSTEM "log4j.dtd" > I would like to use the CATALINA_HOME environment variable in the configuration file  First, adding a system variable in your application startup process, such as: System.setProperty(“ HostName “, InetAddress.getLocalHost().getHostName()); Then reference this HostName system variable in your Log4j.xml configuration file, something like the following:

Is there a way to set default value if the environment variable doesn't , If you want to use environment variables in log4j, for example, you want to control the -Dlog4j.configuration=file:${PARENT}/conf/log4j.xml . 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.

You want to use dynamic values in your log4j xml configuration file. For example, you have a File Appender, and the path to that log file depends on the environment the app Now, we need to pass the environment variable. Configuration with XML. Log4j can be configured using two XML flavors; concise and strict. The concise format makes configuration very easy as the element names match the components they represent however it cannot be validated with an XML schema.

Comments
  • I just commented on the most upvoted answer and explained my reasoning. I've also just now upvoted the answer I accepted, for what it's worth.
  • You can also specify a default using the following syntax ${env:LOG_PATH:-/default/path} where /default/path will be used if LOG_PATH is not set.
  • I specifically asked how to do this without having to set them all as -D parameters, so this doesn't answer my question at all.
  • Does the syntax you show there, ${APP_LOG_ROOTDIR} look at system environment variables, not just Java system properties? My understanding (and experience) has been that it only looks at Java system properties, not environment variables.
  • @DerekLewis Yes, the syntax looks at system environment variables. Those variables are available to tomcat at startup, similar to the variables set by tomcat via the setenv.bat script. Note, i've only used this on windows. This isn't an issue for me on *nix so never I had to use this solution.