Hi Kafka Dev, I created KIP-168 to propose adding a metric to emit total topic count in a cluster. The metric will be emited by the controller.
The KIP can be found here (https://cwiki.apache.org/confluence/display/KAFKA/KIP-168%3A+Add+TotalTopicCount+metric+per+cluster) and the assciated JIRA improvement is KAFKA-5461 (https://issues.apache.org/jira/browse/KAFKA-5461) Appreciate all the comments. Best, Abhishek
