Status

Current state: Under Discussion

Discussion thread: here [Change the link from the KIP proposal email archive to your own email thread]

JIRA: here [Change the link from KAFKA-1 to your own ticket]

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

We all know that it is possible to listen to mutliple topics by using the kafka-console-consumer CLI tool and using the --include  argument. While I find this functionality useful personally, there are no way to know from which topic the message came from. This is useful to me, especially during development of projects that publishes message to Kafka, and I don't see a way to do it, neither with kafka-console-consumer nor with other 3rd party tools I know of. I find the change to be quite trivial, it's definitely helpful to me, and I wish that it helps others that may need it.

Public Interfaces

Currently --property  exists for printing extra information such as key , headers , partition, etc...

This led me to propose adding –-property print.topic=true to the kafka-console-consumer  tool.

Printing a message with the "print.topic" set to "true" would produce this output:

Topic:topic    value

Printing a message with these properties:

"print.offset" -> "true"
"print.topic" -> "true"
"print.timestamp" -> "true"
"print.partition" -> "true"
"print.key" -> "true"

produces the following output:

NO_TIMESTAMP    Partition:0    Offset:123    Topic:topic    key    value

Proposed Changes

Adding –property print.topics=true  would print the topic of the message. The topic() accessor already exists in the consumerRecord  object.

Compatibility, Deprecation, and Migration Plan

No impact on existing user, as this change will only add a new –property print.topic=true  option in the kafka-console-consumer  tool.

Rejected Alternatives

-