Ignore wrong date value

[mitabrev]

I tried like that for example:

    if [retry_time] == "0" {
    mutate {
    convert => { "retry_time" => "integer" }
    }
    } else {
    date {
   match => ['retry_time', 'UNIX']
   target => 'retry_time'
   }
    }

But not sure if it's ok.