title: is it possible to limit value search only in specific path partially with logstash-logback-encoder for masking
body: <p>is it possible to limit search for value within logstash-logback-encoder by specific path?
  Say I wanna to mask emails only in message.
  I have logs like :</p>
  <blockquote>
  <p>{&quot;message&quot;:&quot;[email=email@example.com,phone=123]&quot;,&quot;another_path&quot;:&quot;mail@leaveit.com&quot;}</p>
  </blockquote>
  <p>So I need to replace only email@example.com with xxxx, thus leave mail@leaveit.com as logger_name</p>
  <blockquote>
  <p>{&quot;message&quot;:&quot;[email=xxxx,phone=123]&quot;,&quot;another_path&quot;:&quot;mail@leaveit.com&quot;}</p>
  </blockquote>
  <p>Thus I can use something like</p>
  <pre><code>&lt;appender name=&quot;CONSOLE&quot; class=&quot;ch.qos.logback.core.ConsoleAppender&quot;&gt;
      &lt;!-- see https://github.com/logfellow/logstash-logback-encoder#identifying-field-values-to-mask-by-value --&gt;
      &lt;encoder class=&quot;net.logstash.logback.encoder.LogstashEncoder&quot;&gt;
          &lt;jsonGeneratorDecorator class=&quot;net.logstash.logback.mask.MaskingJsonGeneratorDecorator&quot;&gt;
              &lt;value&gt;(\w+@\w+\.\w+)&lt;/value&gt;
          &lt;/jsonGeneratorDecorator&gt;
      &lt;/encoder&gt;
  &lt;/appender&gt;
  </code></pre>
  <p>it affects both passes</p>