Create alert based on transformation value

Hi everyone,

I’m quite new to Grafana and have been tasked to look into an alert that is triggered based on two different log groups.

We have a ECS service that once running it will send a file to a 3rd party who will process the file on their end and send back a MSG file within 24 hours and log the details to a Lambda. We want to be able to check the a file that has been processed by the 3rd party provider and alert if we do not see the message file back within the time frame so the 3rd party can investigate.

Each service runs at specific times of the day.
The log will say “successfully created file $filename” as it sends the file and once its processed we should receive “MSG file received for File $filename”.

I’m aware that it is hard to check if a specific file has not been processed in terms of variables in a query level and have mentioned that to the team.

I’ve been able to create a dashboard that has a transformation that checks the two log groups for specific strings and the transformation will display the difference between the logs which would be a quick win for us as we can just check if the difference is above 0 as we shouldn’t see a difference between them.

Has anyone been able to add an alert to a transformation value?

Any support on this would be great!
Thanks in advance

Any joy? Currently looking at setting up an alert for a transformation but not sure if it’s possible.