Opensearch alerting -text message in action

Hi, I using opensearch 2.8.0. I need config alerting and sending alerts over smtp. So alerting is functional and sends emails. But I need modify text message in mail. Can opensearch sending in messages text content from index? I using opensearch for logging event from applications. And I need send log from application in mail body.
how can I configure it?

Thank you for your answers

Yes, try something like this:
In Extraction Query:
“size”: 1,

In Action Message:
Monitor {{}} just entered alert status. Please investigate the issue.

  • Trigger: {{}}
  • Severity: {{ctx.trigger.severity}}
  • Period start: {{ctx.periodStart}}
  • Period end: {{ctx.periodEnd}}
  • Message: {{ctx.results.0.hits.hits.0._source.@message}}
  • Alerts: {{ctx.results}}

Thank you very much. It s working