I'm working on a custom layout to mask sensitive information in our production logs.

One of the key features is to use regular expressions - so i need the syntax of logback.xml to support the special characters in regex - including $.

I have searched high and low with google - and read the source a bit.  but it looks like there is no mechanism to escape this character.

Here is a fragment of my config file: 

...

       <layout class="log.PIIFilterLayout">

          <pattern>:%d{HH:mm:ss.SSS} [%thread] %-5level %logger{1} - %msg %n</pattern>

          <!-- adhoc patterns -->

          <regex>mdn='(.+)'</regex>

          <regex>accountName=(.+)$</regex>

...

I have tried: 

  - $

  - \$

  - \\$

  - &#36;

 

No matter what - i get this: 

Failed to instantiate [ch.qos.logback.classic.LoggerContext]

Reported exception:

java.lang.IllegalArgumentException: Failed to parse input [accountName=(.+)\\$]

at ch.qos.logback.core.util.OptionHelper.substVars(OptionHelper.java:119)

at ch.qos.logback.core.joran.spi.InterpretationContext.subst(InterpretationContext.java:159)

at ch.qos.logback.core.joran.action.NestedBasicPropertyIA.body(NestedBasicPropertyIA.java:87)

at ch.qos.logback.core.joran.spi.Interpreter.callBodyAction(Interpreter.java:295)

at ch.qos.logback.core.joran.spi.Interpreter.characters(Interpreter.java:175)

at ch.qos.logback.core.joran.spi.EventPlayer.play(EventPlayer.java:57)

at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:149)

at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:135)

at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:99)

at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:49)

at ch.qos.logback.classic.util.ContextInitializer.configureByResource(ContextInitializer.java:75)

at ch.qos.logback.classic.util.ContextInitializer.autoConfig(ContextInitializer.java:150)

at org.slf4j.impl.StaticLoggerBinder.init(StaticLoggerBinder.java:85)

at org.slf4j.impl.StaticLoggerBinder.<clinit>(StaticLoggerBinder.java:55)

at org.slf4j.LoggerFactory.bind(LoggerFactory.java:129)

at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108)

at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:302)

at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:276)

at util.LogFactory.getLogger(LogFactory.java:27)

at log.PIITest.<clinit>(PIITest.java:20)

Caused by: ch.qos.logback.core.spi.ScanException: Unexpected end of pattern string

How can i escape $ in logback.xml?

Paul