Hi Ian, no, you don't implement a PropertyProvider for this - this is done by the job implementation for you (JobConsumerManager). The JobConsumerManager collects all active JobConsumer queries their supported topics and provides this information through the topology by registering the PropertyProvider. Basically, you have three choices: either you disable the job consumer on an instance, you change the topics registration property of that service or the consumer manager allows to configure whitelist and blacklist topics. Which in most cases is the easiest solution. A topology change causes the job handling to restart, if you do a consumer change based on that, this results in a new topology event and the job handler will restart again. At least that's how it is implemented right now, as this is the easiest way of implementing it. However, the restart comes with a delay, so if the additional events happen within this delay, you end up with exactly one restart (this is why we have the delay).
Regards Carsten 2013/9/6 Ian Boston <[email protected]> > Hi, > (Probably a question for Carsten). > > Is the right way to implement topology based queue exclusion by > implementing a topology discovery PropertyProvider that provides the > property: > > org.apache.sling.event.jobs.consumer.topics > > containing a , separated list of topics the instance can handle. > > If so I have 2 questions: > > Since this list is topology dependent (depends on which is master) and > will itself have to be generated after a topology change which may > take some time to filter through the discovery hub spoke > implementation, will it cause the Job Queue to restart multiple times > on a relevant property change. ? > > Also, how are Topics excluded from a list of capabilities for each > instance. I have read through the code in the constructor of > TopologyCapabilities and the getPotentialTargets, detectTartgets and I > cant see how to exclude a topic from an instance, only how to include. > What is the best way of excluding a topic from a instance without > having to whitelist all known topics. ? > > Best Regards > Ian > -- Carsten Ziegeler [email protected]
