Only first ValueMasker is applied

[aukevanleeuwen]

Describe the bug
It's up for debate if this is a bug, but at least it is unexpected behaviour to me and I can't find it in the documentation. So filed a bug report anyway.

When configuring multiple ValueMaskers. and both of them would match a certain value, on the first one is applied.

To Reproduce
Steps to reproduce the behavior:

1. Assuming we have two net.logstash.logback.mask.ValueMaskers:

• com.example.MatchesOnStringA which would mask all occurences of "StringA" to "*******"
• com.example.MatchesOnStringB which would mask all occurences of "StringB" to "*******"

2. Use this logback.xml configuration†:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
  <include resource="org/springframework/boot/logging/logback/defaults.xml"/>

  <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
      <encoder class="net.logstash.logback.encoder.LogstashEncoder">
          <jsonGeneratorDecorator class="net.logstash.logback.mask.MaskingJsonGeneratorDecorator">
              <valueMasker class="com.example.MatchesOnStringA"/>
              <valueMasker class="com.example.MatchesOnStringB"/>
          </jsonGeneratorDecorator>
      </encoder>
  </appender>

  <root level="INFO">
      <appender-ref ref="CONSOLE"/>
  </root>
</configuration>

† this is maybe not entirely correct configuration, I've manually trimmed a few lines here and there to make it consise

3. Execute this logger statement:

log.info("StringA and StringB");

4. See the log

Expected behavior
I would expect this to match

******* and *******

But in fact only the first configured ValueMasker is applied, so the result is

******* and StringB

Additional context
I had a look through the sources and I guess it's to be expected because of this code:

    private Object getMaskedValueForCurrentPathAndValue(Object value) {
        JsonStreamContext context = getOutputContext();
        for (ValueMasker valueMasker : valueMaskers) {
            Object maskedValue = valueMasker.mask(context, value);
            if (maskedValue != null) {
                return maskedValue;
            }
        }
        return null;
    }