Can I Delete the Message Field From Logstash?

Yes, you can delete the message field in Logstash if it’s no longer needed after processing. This can be useful for reducing data volume in Elasticsearch or removing redundant information. Here’s a quick guide on how to do it effectively.

Steps to Delete the message Field

1. Process and Extract Necessary Information

   Before deleting message, ensure that you’ve extracted all needed information from it. For example, use filters like grok, json, or kv to parse relevant fields.

2. Use the mutate Filter to Remove message

   Once you’ve extracted the required fields, add a mutate filter to remove the message field:

    

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   filter {
     # Parsing or extraction here (e.g., grok)
     mutate {
       remove_field => ["message"]
     }
   }
   
   

   This will delete message from each event, leaving only the parsed fields you’ve extracted.

3. Conditional Deletion (Optional)

   If you want to remove message only under certain conditions, you can wrap the mutate filter in a conditional statement:

    

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   filter {
     if [some_field] == "some_value" {
       mutate {
         remove_field => ["message"]
       }
     }
   }
   
   

Benefits and Caution

Deleting the message field can save storage space and make your data cleaner in Elasticsearch. However, be cautious—if you need to refer to the original log content later, removing message will make that impossible unless stored elsewhere. Consider testing this configuration in a staging environment first.

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