How to set the SERVICE field of the logs?

[skwokie]

Thanks for gathering all the info and creating this repo. It has made my life (and I believe many of the others') easier.
I'd like to ask how the SERVICE field of the logs are set when the logs are being sent to the datadog platform. My situation:

1. My logs forwarder and the function apps (APPS) that generates the logs have a 1-to-many relationship; therefore, I cannot statically set the DD_SERVICE env var for the function app of the logs forwarder.
2. Right now, the SERVICE field is by default set with the name of the APPS.
3. We need the SERVICE field to be set with the value of a tag of the APPS.
4. Another option is to massage the the SERVICE field (which is by default with the name of the APPs), what is the best practice to do it?

Thanks so much in advance. Looking forward to hearing from you.