Update/rename nested field

[bvoros (Bertalan Voros)]

Hello All,

What is the best way to rename a nested field?

I would like to do the following:

if [filed][subfield]
rename it to [field]

Would it make sense to add a temporary field with the value of the original, drop the original then rename the temporary or is there a better way?

Any help appreciated,

[bvoros (Bertalan Voros)]

Does this make sense?

filter{
    if 'filebeat' in [tags] or 'beats_input_codec_plain_applied' in [tags] {
        if [name] in [host] {
            mutate {
                add_field => { "host_name" => %{[host][name]} }
            }
            drop {
                remove_field => [ "host" ]
            }
            mutate {
                rename => [ "host_name", "host" ]
            }

        }
    }
}

[Badger]

Yes, if you want to move [host][name] to [host] you will have to use a temporary field to store the value.

Note that you have the option of moving it the other way

if ! [host][name] { mutate { rename => { "[host]" => "[host][name]" } } }

[bvoros (Bertalan Voros)]

Thanks, the only thing is that the [host] field is already there.
Could drop the index though, will ponder the benefit of going either way.
Thanks a lot for your help once again.