Logstash.conf from 5.4 no longer working in 6.3

Elastic Stack Logstash
1

Working on my logstash.conf grok statement.

It seems the part that is not working is the final bit that says:

if [tags] == [] {
mutate {
remove_field => ["tags"]
}
}

This is logstash 6.3.

Any idea where I've gone wrong. It works in 5.4 which is what I am upgrading.

2

That no longer works in LS 6. You can do it in ruby if having an empty array in your document offends you.

    ruby {
        code => '
            if event.get("tags") == []
                event.remove("tags")
            end
        ' 
    }