Logback with logstash encoder, custom ValueMaskSupplier

[charu-jain-sapient]

I want my logs to appear in JSON format. Hence have used logback-logstash-encoder for logging purposes.

I am able to implement most of my usecases except the masking one.
The description given in https://github.com/logfellow/logstash-logback-encoder#masking lacks examples of how to do custom implementation of ValueMaskSupplier and ValueMasker's

Can anyone points me to some examples which helps me to understand it better.

Also, I have 2 more queries:

1. I am implementing this logstash lib in my spring boot project and all regex patterns to test, against a message will come from configurations i.e application.properties.

in my application.properties, configuration looks like:

log.masking.maskPattern=(\w+@\w+\.\w+)

Now how could i access it below in ${maskPattern}, as its not able to retrieve value:

<?xml version="1.0" encoding="UTF-8"?>
<configuration debug="true">
	<springProperty scope="context" name="maskingEnabled" source="log.masking.enabled"/>
	<springProperty scope="context" name="maskPattern" source="log.masking.maskPattern"/>
	<appender name="console_masking" class="ch.qos.logback.core.ConsoleAppender">
		<encoder class="net.logstash.logback.encoder.LoggingEventCompositeJsonEncoder">
			<jsonGeneratorDecorator class="net.logstash.logback.mask.MaskingJsonGeneratorDecorator">
				<value>${maskPattern}</value>
				<path>Message/*</path>
			</jsonGeneratorDecorator>
			<providers/>
		</encoder>
	</appender>
	<root level="DEBUG">
		<appender-ref ref="console_masking"/>
	</root>
</configuration>

2. My masking usecase says that "value" tag can contains any number of comma seperated regex patterns to be tested against a message. Also it can have a link to a file also, which can contain regex patterns.

Can anyone helps me to understand how can I achieve this usecase as I didn't get any online example to create a custom MaskingJsonGeneratorDecorator.

Please help.

[charu-jain-sapient]

@philsttr : Requesting your help here.