GCP Alert email customization - google-cloud-platform

Question

I am trying to add more text to 'alert' email that Google send when something happens in cloud. For example I build an log based alert and when some threshhold reached then 'alert' email send. I read multiple time the document: Using Markdown and variables in documentation templates but whatever I put into 'Documentation' field come as simple text - without actual value of the field :( For example I receive an email with:
Error Text: ${log.extracted_label.rawLogIndex}
For example I have a log entry like this:
I want the value of labels\error_stack to be send in alert email - how I can do that ? Could you add an example ?

Answer 1

You can include the log data using the variables in the document section of the alert policy. For this log-based alert needs to be created.
To answer your question: In order to use the variable in documentation, you need to create a label for your logs. You can create a label using extractor expressions. These expressions will notify the cloud logging to extract the label's value from the logs you defined.
This document will help to understand the labels for log-based metrics along with example. You can follow this tutorial to create a log-based alerts.