Do we have Layout Pattern tag support for OpenTelemetryAppender in logback file?

[ff-amarkande]

Discussed in https://github.com/open-telemetry/opentelemetry-java-instrumentation/discussions/11695

^{Originally posted by **ff-amarkande** June 28, 2024} Hi Team, Trying to format the log message with custom layout for example, refer following logback file ``` %date %level [%thread] %logger{36} [%file:%line] [requestId=%X{requestId}] %msg%n ``` Custom layout code - Created **CustomPatternLayout** class for formatting by **extending PatternLayout class** ``` defaultConverterMap.put( "msg", CustomMessageConverter.class.getName() ); ``` Code `public class CustomMessageConverter extends MessageConverter { /** * @see ch.qos.logback.core.pattern.Converter#convert(java.lang.Object) */ @Override public String convert( ILoggingEvent event ) { return super.convert( new LoggingEventWrapper( event ) ).replace( System.getProperty( "line.separator" ), "" ); } private static class LoggingEventWrapper implements ILoggingEvent { private ILoggingEvent event; private String formattedMessage = null; public LoggingEventWrapper( ILoggingEvent event ) { super(); this.event = event; } @Override public String getThreadName() { return event.getThreadName(); } @Override public Level getLevel() { return this.event.getLevel(); } @Override public String getMessage() { return this.event.getMessage(); } @Override public Object[] getArgumentArray() { return LoggingUtil.encloseInQuotes( event.getArgumentArray() ); } @Override public String getFormattedMessage() { if ( null != formattedMessage ) { return formattedMessage; } formattedMessage = event.getMessage(); if ( event.getArgumentArray() != null ) { if ( event.getArgumentArray()[0] instanceof LoggingEvents ) { LoggingEvents e = (LoggingEvents)event.getArgumentArray()[0]; formattedMessage = // method to format and create a custom log with key=value pair } else { formattedMessage = MessageFormatter.arrayFormat( event.getMessage(), LoggingUtil.encloseInQuotes( event.getArgumentArray() ) ).getMessage(); } } return formattedMessage; } //Removed other override methods }` However when tried with **OpenTelemetryAppender** , log message is not formatted as per the layout. ``` true true true true true * %date %level [%thread] %logger{36} [%file:%line] [requestId=%X{requestId}] %msg%n ``` Excepted `2024-06-28 12:59:51,360 INFO [localhost-startStop-1] EventLogger[SystemInfoProvider.java:54] [ requestId=Test-123] [eventChannel=CONFIGURATION, eventId=SYSTEM_INFO, message="Event to indicate system information", machineId=machine-id-1]` Actual `Event to indicate system information ` Following is custom message formed inside **getFormattedMessage method** `[eventChannel=CONFIGURATION, eventId=SYSTEM_INFO, message="Event to indicate system information", machineId=machine-id-1]`

[laurit]

This is not supported. Instead of having requestId etc. as part of the message isn't it more useful to capture it as an attribute.

[ff-amarkande]

Is support for adding layout pattern tag planned in near future? Also is there any other way how we can customise the log message using OpenTelemetryAppender?

[laurit]

Is support for adding layout pattern tag planned in near future?

I'm not aware of any plans to support this. For such features we rely on interested parties submitting pull requests.

[ff-amarkande]

Is there any document which captures the details on how to contribute(create branch, raise PR, all the prerequisite etc) so that I can create PR for the same?

[laurit]

Is there any document which captures the details on how to contribute(create branch, raise PR, all the prerequisite etc) so that I can create PR for the same?

There isn't, nothing special is needed just fork the project and submit a PR from your fork. When you submit the PR you'll have to sign the CLA, the github bot that verifies the CLA will add comment to your PR with the details.