Currently producers cannot detect if a topic is consumed by someone or not themselves. If you want to know globally if a specific topic is consumed by anyone or not, you can query the ZK for all the consumer groups, and search if they contain the topic name.
Guozhang On Wed, Mar 19, 2014 at 1:01 PM, Ian Friedman <i...@flurry.com> wrote: > Hey Todd, > > For my purposes, I wrote a Partitioner that reads all of the > ConsumerOffsets for a particular group from Zookeeper, and then sends its > message to the one with least lag (with some probabilistic weighting thrown > in to prevent it from getting overwhelmed). I basically read and > reimplemented the code from ConsumerOffsetChecker.scala to do this. Does > that help at all? Would it help to see my code? > > --Ian > > On Mar 19, 2014, at 12:47 PM, Todd Gatts <tga...@us.ibm.com> wrote: > > > > > > > I'd like to avoid creating messages for a topic is the topic currently > has > > no consumers. Is there a way a producer can subscribe to the number of > > consumers of a topic? Or if that's not possible, can a producer request > > the current number of consumers of a topic? > > > > The searchable hadoop kafka topic didn't return anything for "no > consumer" > > or "zero consumers", and a find on "zero" or "count" on the documentation > > html page found lots of matches, but none about knowing the number of > > consumers. > > > > I'm certain I can code a solution around this problem, but I'd hate to > > reinvent the wheel for such a straightforward problem. > > > > Todd Gatts > > -- -- Guozhang
