Kafka streams using context forward from processor called in dsl api











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I have a processor and would like to call context.forward() in it. However I feel like I need to set a sink topic for it to actually get forwarded. If I was using the Toplogy I would just .addSource(), .addProcessor(), .addSink(). However with the DSL I have a StreamsBuilder/KStream. Is there anyway to use context.forward() when calling a processor from the dsl?



NOTE: I need to use a processor instead of a transform as I have custom logic on when to forward records down stream.



stream.process(() -> new WindowAggregatorProcessor(storeName), storeName);









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    up vote
    0
    down vote

    favorite












    I have a processor and would like to call context.forward() in it. However I feel like I need to set a sink topic for it to actually get forwarded. If I was using the Toplogy I would just .addSource(), .addProcessor(), .addSink(). However with the DSL I have a StreamsBuilder/KStream. Is there anyway to use context.forward() when calling a processor from the dsl?



    NOTE: I need to use a processor instead of a transform as I have custom logic on when to forward records down stream.



    stream.process(() -> new WindowAggregatorProcessor(storeName), storeName);









    share|improve this question
























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      I have a processor and would like to call context.forward() in it. However I feel like I need to set a sink topic for it to actually get forwarded. If I was using the Toplogy I would just .addSource(), .addProcessor(), .addSink(). However with the DSL I have a StreamsBuilder/KStream. Is there anyway to use context.forward() when calling a processor from the dsl?



      NOTE: I need to use a processor instead of a transform as I have custom logic on when to forward records down stream.



      stream.process(() -> new WindowAggregatorProcessor(storeName), storeName);









      share|improve this question













      I have a processor and would like to call context.forward() in it. However I feel like I need to set a sink topic for it to actually get forwarded. If I was using the Toplogy I would just .addSource(), .addProcessor(), .addSink(). However with the DSL I have a StreamsBuilder/KStream. Is there anyway to use context.forward() when calling a processor from the dsl?



      NOTE: I need to use a processor instead of a transform as I have custom logic on when to forward records down stream.



      stream.process(() -> new WindowAggregatorProcessor(storeName), storeName);






      apache-kafka-streams






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      asked Nov 13 at 22:25









      Chris

      3083416




      3083416
























          1 Answer
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          up vote
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          down vote



          accepted










          stream.process() is a terminal operation in the DSL. You can use stream.transform() instead to get an output stream. A Transformer is basically the same as a Processor.






          share|improve this answer





















          • With a transformer dont you need to return the value you want to go down stream. In my case I have a context.schedule() that may or may not want to forward content. For your suggestion to work I would need to always have transform() return null and the have context.forward() pass the value to the next operation. Which I dont think will work?
            – Chris
            Nov 14 at 0:37










          • What you say will work. Btw: we are currently adding a "FlatTransformer" to allow you to emit more than one value via return. context.forward will still be available (it's disadvantage is, that's not type safe; but it works).
            – Matthias J. Sax
            Nov 14 at 3:59













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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          1
          down vote



          accepted










          stream.process() is a terminal operation in the DSL. You can use stream.transform() instead to get an output stream. A Transformer is basically the same as a Processor.






          share|improve this answer





















          • With a transformer dont you need to return the value you want to go down stream. In my case I have a context.schedule() that may or may not want to forward content. For your suggestion to work I would need to always have transform() return null and the have context.forward() pass the value to the next operation. Which I dont think will work?
            – Chris
            Nov 14 at 0:37










          • What you say will work. Btw: we are currently adding a "FlatTransformer" to allow you to emit more than one value via return. context.forward will still be available (it's disadvantage is, that's not type safe; but it works).
            – Matthias J. Sax
            Nov 14 at 3:59

















          up vote
          1
          down vote



          accepted










          stream.process() is a terminal operation in the DSL. You can use stream.transform() instead to get an output stream. A Transformer is basically the same as a Processor.






          share|improve this answer





















          • With a transformer dont you need to return the value you want to go down stream. In my case I have a context.schedule() that may or may not want to forward content. For your suggestion to work I would need to always have transform() return null and the have context.forward() pass the value to the next operation. Which I dont think will work?
            – Chris
            Nov 14 at 0:37










          • What you say will work. Btw: we are currently adding a "FlatTransformer" to allow you to emit more than one value via return. context.forward will still be available (it's disadvantage is, that's not type safe; but it works).
            – Matthias J. Sax
            Nov 14 at 3:59















          up vote
          1
          down vote



          accepted







          up vote
          1
          down vote



          accepted






          stream.process() is a terminal operation in the DSL. You can use stream.transform() instead to get an output stream. A Transformer is basically the same as a Processor.






          share|improve this answer












          stream.process() is a terminal operation in the DSL. You can use stream.transform() instead to get an output stream. A Transformer is basically the same as a Processor.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 13 at 23:32









          Matthias J. Sax

          27.5k34572




          27.5k34572












          • With a transformer dont you need to return the value you want to go down stream. In my case I have a context.schedule() that may or may not want to forward content. For your suggestion to work I would need to always have transform() return null and the have context.forward() pass the value to the next operation. Which I dont think will work?
            – Chris
            Nov 14 at 0:37










          • What you say will work. Btw: we are currently adding a "FlatTransformer" to allow you to emit more than one value via return. context.forward will still be available (it's disadvantage is, that's not type safe; but it works).
            – Matthias J. Sax
            Nov 14 at 3:59




















          • With a transformer dont you need to return the value you want to go down stream. In my case I have a context.schedule() that may or may not want to forward content. For your suggestion to work I would need to always have transform() return null and the have context.forward() pass the value to the next operation. Which I dont think will work?
            – Chris
            Nov 14 at 0:37










          • What you say will work. Btw: we are currently adding a "FlatTransformer" to allow you to emit more than one value via return. context.forward will still be available (it's disadvantage is, that's not type safe; but it works).
            – Matthias J. Sax
            Nov 14 at 3:59


















          With a transformer dont you need to return the value you want to go down stream. In my case I have a context.schedule() that may or may not want to forward content. For your suggestion to work I would need to always have transform() return null and the have context.forward() pass the value to the next operation. Which I dont think will work?
          – Chris
          Nov 14 at 0:37




          With a transformer dont you need to return the value you want to go down stream. In my case I have a context.schedule() that may or may not want to forward content. For your suggestion to work I would need to always have transform() return null and the have context.forward() pass the value to the next operation. Which I dont think will work?
          – Chris
          Nov 14 at 0:37












          What you say will work. Btw: we are currently adding a "FlatTransformer" to allow you to emit more than one value via return. context.forward will still be available (it's disadvantage is, that's not type safe; but it works).
          – Matthias J. Sax
          Nov 14 at 3:59






          What you say will work. Btw: we are currently adding a "FlatTransformer" to allow you to emit more than one value via return. context.forward will still be available (it's disadvantage is, that's not type safe; but it works).
          – Matthias J. Sax
          Nov 14 at 3:59




















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