Hi, sorry for the delay,
I was discussing your case with the rest of the team and currently, as you mentioned well, the functionality of adding <label> is only active for
JSON format logs.
At the moment there are no developments in progress so that this functionality can be understood for the rest of the log formats.
a possible solution but perhaps a bit complicated to do, would be to be able to use
out_format.
Maybe that way you could modify the log but you will have to verify decoders and rules, in addition to having to create new decoders so that they can extract this new information.
perhaps in the future that functionality may be added to support different types of logs.
Sorry for the inconveniences.
Best regards.