Losgtash runs successfully but I doesn't see any logs on command line using stdout

Hi all
On logstash system, it receives the syslog messages from my source syslog servers on port 514.
Below is the code I have and I see that logstash is running successfully but I don't see output. Can any one help here?

input {
  tcp {
    port => 514
    type => syslog
  }
  udp {
    port => 514
    type => syslog
  }
}

filter {
  if [type] == "syslog" {
    grok {
		match => { "message" => "%{GREEDYDATA:message}" }
        
    }
  }
}

output {
  stdout { codec => rubydebug }
}