Let's imagine we have string
some text aaabbbccc another text
We want to extract bbb.
we can use "embedded" regex (https://www.elastic.co/guide/en/logstash/current/plugins-filters-grok.html Custom Patterns "option 1"
But it's more neatly to extract this logic to custom pattern in custom pattern file.
we can use custom pattern in custom pattern file ("option 2")
Now we have excess variable bvar.
Of course we can mutate and remove bvar, but does another method exist to not create (and remove further) bvar variable?
I tried syntax like
but it doesn't allow omit variable.