Truncate individual log messages above a certain character count with Spring logback - spring

Question

I would like to reduce the size of certain logs using logback (I attempted to use Pattern layout with with a pattern of %.100000msg to limit the max size to one hundred thousand but had no luck), the large(over 1 million characters caused by a few REST GET calls) logs are causing Elastic to slow down when searching for certain information.
What would be the best practice to overcome this?
<include resource="org/springframework/boot/logging/logback/base.xml"/>
<appender name="Console"
class="ch.qos.logback.core.ConsoleAppender">
<layout class="ch.qos.logback.classic.PatternLayout">
<Pattern>
%.30msg
</Pattern>
</layout>
</appender>
<logger name="" level="INFO"/>

Answer 1

I solved this by refering to this documentation to create a custom converter. The property was an extra, it was implemented to allow for configuration within the xml file.
<property scope="context" name="max-message-length" value="100000"/>
<conversionRule conversionWord="boundedMsg"
converterClass="za.co.ksdc.qadee.config.TruncationCustomLogConverter" />
The following java class was implemented to truncate the log message:
public class TruncationCustomLogConverter extends ClassicConverter {
#Override
public String convert(ILoggingEvent event) {
int maxMessageLength = Integer.parseInt(getContext().getProperty("max-
message-length"));
String formattedMessage = event.getFormattedMessage();
if (formattedMessage == null ||
formattedMessage.length() < maxMessageLength) {
return formattedMessage;
}
return new StringBuilder(maxMessageLength)
.append(formattedMessage, 0, maxMessageLength)
.toString();
}
}