Topic title validator / error checker?

[amkearns-usgs]

I had been spending a while debugging issues on a small script causing metadata timeout errors when I discovered that the issue was the result of a leading whitespace character in the topic title. While I was able to (eventually) diagnose and fix the problem, the appearance of the error being server-side led us to believe the problem was one related to permissions and not due to a malformed topic title.

This is a feature request to include a validator for title characters. I can make a method to do this myself if necessary -- I'd just like for cases where the topic title is bad to have an obvious error message for debugging circumstances like these.

[jeffwidman]

Does the Java client do any validation like this? It certainly sounds like it'd be useful...

[mmenbawy]

No validation happens in the java client.
NewTopic.java: https://github.com/apache/kafka/blob/a73bf5931aaf1510f0efa86bc7d61ff8aab046c2/clients/src/main/java/org/apache/kafka/clients/admin/NewTopic.java#L47

TopicPartition.java: https://github.com/apache/kafka/blob/a73bf5931aaf1510f0efa86bc7d61ff8aab046c2/clients/src/main/java/org/apache/kafka/common/TopicPartition.java#L32

However, it's present in the Scala client
https://github.com/apache/kafka/blob/8007211cc982d8458223e866c1ee7d94b69e0249/core/src/main/scala/kafka/common/Topic.scala#L33

[mmenbawy]

@dpkp @jeffwidman Are you willing to add this feature? Should someone work on it?

[dpkp]

We do validate topic names in consumer, but not in producer. Should be easy enough to add to producer.