Logstash not pushing logs to kafka after it started

Hi All,
I am new to logstash and iam trying to building a pipeline to push logs from a logdirectory to the kafka topic
so i have below config file

input {
   file {
    path => "/home/ubuntu/log_dir/log_json.json"
    start_position => "beginning"
    codec => "json"
  }
}
filter {
    json {
        source => message
    }
}
output {
  kafka {
    bootstrap_servers => "localhost:9092"
    codec => plain {
        format => "%{message}"
    }
    topic_id =>  "my_topic"
  }
}

After i launched the kafka server , i started the logstash service with below command

bin/logstash --path.settings /etc/logstash/ -f /etc/logstash/conf.d/json_log.conf --config.reload.automatic

And i found the service started and stopping with
"Successfully started logstash API endpoint{:port=9600}"

further i am not seeing the logs being parsed to the kafka topic

Appreciated if anyone can help on this?

Thanks