+FORMAT syntax works for @timestamp field only?

[jetnet]

can some other timestamp field be used with +FORMAT syntax?

index => "${ELASTICSEARCH_INDEX}.%{+yyyy.MM.dd}"

the above config line would use @timestamp as the input for the format definition, but I'd like to use some other field.
Thanks!

[jetnet]

since I don't need the default @timestamp field in the index, but would like to use the +FORMAT syntax for the index naming, I have to use the following workaround (my "local" timestamp field is server_time in ISO8601 format):

mutate {
        copy => { "server_time" => "@timestamp" }
        add_field => { "[@metadata][date]" => "%{+yyyy.MM.dd}" }
        remove_field => [ "@version", "@timestamp", "host", ...]
}

and in the ES output:

index => "${ELASTICSEARCH_INDEX}-%{[@metadata][date]}"

would be glad if someone could share a more elegant solution.

[Badger]

@jetnet

can some other timestamp field be used with +FORMAT syntax?

No, it always uses @timestamp.

[jetnet]

thanks for confirming that!
I'm asking myself: why didn't they mention this point in the documentation? Just one small sentence would save a lot of time...