gistfile1.txt

input {
    tcp {
        type   => 'json-logger'
        port   => 3517
        format => "json_event"
    }
}
filter {
    mutate {
        # Convert hostname => @source_host, because it's overwritten
        # by logstash on reception of event
        type    => "json-logger"
        replace => [ "@source_host", "%{source_host}" ]
        remove  => [ "source_host" ]
    }
}
output {
 # not relevant
}