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);









share|improve this question


























    0















    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
























      0












      0








      0








      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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      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 13 '18 at 22:25









      ChrisChris

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      3253417






















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          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 '18 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 '18 at 3:59











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          1 Answer
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          active

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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          1














          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 '18 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 '18 at 3:59
















          1














          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 '18 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 '18 at 3:59














          1












          1








          1







          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 '18 at 23:32









          Matthias J. SaxMatthias J. Sax

          29.6k35278




          29.6k35278












          • 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 at 3:59


















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