Formatted values in logstash are not displayed

Formatted values in logstash are not displayed.

  • want to
    I would like to split the log collected by logstash and get it by dissect, and check each in a different field in Kibana.

  • issue
    However, the variable name on the logstash is displayed instead of the retrieved value.
    How can I display the retrieved value?

  • experiment
    input:

    A	B
    

    settings:

    ... snip ...
    filter {
      dissect {
        mapping => {
          "message" => "%{ia}	%{ib}"
        }
      }
      mutate {
        add_field => { "a" => "%{ia}" }
        add_field => { "b" => "%{ib}" }
      }
    }
    

    expect:

    "a" => "A",
    "b" => "B"
    

    actual:

    "a" => "%{ia}",
    "b" => "%{ib}"
    

In Kibana, it looks like this

Was it the logstash category, not Kibana?
I apologize for that.
I hope someone can answer my question.

The problem is solved in this thread, and I'll write down the URL.