Can't pull kafka messages into logstash and then to elasticsearch

Hello,

I am getting this in my logstash log

"{:timestamp=>"2016-04-04T19:27:10.116000+0000", :message=>"Flushing buffer at interval",
:instance=>"#<LogStash::Outputs::ElasticSearch::Buffer:0x635fc4ba operations_mutex=#Mutex:0x6d9836a1,
max_size=500, operations_lock=#Java::JavaUtilConcurrentLocks::ReentrantLock:0x69a7afca,
submit_proc=#Proc:0x314247a0/home/t/logstash-2.2.2/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.5.1-java/lib/logstash/outputs/elasticsearch/common.rb:57,
logger=#<Cabin::Channel:0x7502b298 metrics=#<Cabin::Metrics:0x4234fde metrics_lock=#Mutex:0x24a36adf,
metrics={}, channel=#<Cabin::Channel:0x7502b298 ...>>, subscriber_lock=#Mutex:0x61124ce1,
level=:debug, subscribers={12906=>#<Cabin::Outputs::IO:0x1f274674 io=#<File:/home/t/logstash-2.2.2/var/log/kafka_logstash.log>,
lock=#Mutex:0x20ed32dd>}, data={}>, last_flush=2016-04-04 19:27:09 +0000, flush_interval=1, stopping=#Concurrent::AtomicBoolean:0x1d435217,
buffer=[], flush_thread=#<Thread:0x494e778a run>>", :interval=>1, :level=>:debug, :file=>"logstash/outputs/elasticsearch/buffer.rb",
:line=>"90", :method=>"interval_flush"} "

This is my config

input {

kafka {
zk_connect => "blah.com:2181"
topic_id => "f5-logs-wc1"
codec => plain {
format => "%{message}"
}
}
}

filter {

    grok {
      break_on_match => false
      match => [ "message", "%{SYSLOGTIMESTAMP} %{HOSTNAME:logsource} %{LOGLEVEL:severity_label} %{SYSLOGPROG}: %{GREEDYDATA:info}" ]
    }
    mutate {
        gsub => [
            "severity_label", "err", "error",
            "severity_label", "info", "informational",
            "severity_label", "crit", "critical"
        ]

    remove_field => ["message","host"]
     
    }        

}

output {

     elasticsearch {
         hosts => [  "blah1.com:9200", "blah2.com:9200"]
         index => "f5-%{+YYYY.MM.dd}"
                 }


  stdout { codec => rubydebug }

       }

I have verified that topic has data. So writing to kafka is working

Try taking the filter out and only output to debug. Also run Logstash using the --debug, https://www.elastic.co/guide/en/logstash/current/command-line-flags.html

After it is up and running push messages to the topic.