Oh, nice. Thanks, Daniel! That’s much nicer than my ham-handed approach.
Thanks, John On Thu, Nov 19, 2020, at 17:44, Daniel Hinojosa wrote: > Hope this helps, I tried copying your code into a sample application. I got > it to compile with the implicits all resolving. I think the trick was there > were two implementations for Windowing Serdes. You just need to block one > from the imports. See if that fits with what you are doing. Oh also, I > noticed that the types were not resolving when calling builder.stream, so I > put [String, String] in the builder. Here is a gist, which formats better. > > https://gist.github.com/dhinojosa/390f3a98d271272bbea90765cb58e735 > > import java.time.Duration > import java.util.Properties > > import org.apache.kafka.common.config.Config > import org.apache.kafka.streams.Topology > import org.apache.kafka.streams.kstream.{SessionWindows, Windowed} > import org.apache.kafka.streams.scala.Serdes.{timeWindowedSerde => _, _} > import org.apache.kafka.streams.scala.kstream.{Consumed, Grouped, > Materialized, Produced} > import org.apache.kafka.streams.scala.{ByteArraySessionStore, StreamsBuilder} > > class SampleStream { > def createTopology(conf: Config, properties: Properties): Topology = { > > implicit val produced: Produced[Windowed[String], Long] = > Produced.`with`[Windowed[String], Long] > > implicit val grouped: Grouped[String, String] = > Grouped.`with`[String, String] > > implicit val consumed: Consumed[String, String] = > Consumed.`with`[String, String] > > implicit val materialized: Materialized[String, Long, > ByteArraySessionStore] = Materialized.`with`[String, Long, > ByteArraySessionStore] > > val builder: StreamsBuilder = new StreamsBuilder() > > builder > .stream[String, String]("streams-plaintext-input") > .groupBy((_, word) => word) > .windowedBy(SessionWindows.`with`(Duration.ofMillis(60 * 1000))) > .count() > .toStream > .to("streams-pipe-output") > > builder.build() > } > } > > > > > On Thu, Nov 19, 2020 at 7:24 AM John Roesler <vvcep...@apache.org> wrote: > > > Hi Eric, > > > > Sure thing. Assuming the definition of ‘produced’ you had tried in your > > code, it’s just: > > > > ... > > .toStream.to("streams-pipe-output")(produced) > > > > As far as the json serde goes, I think that I wrote an example of using > > Jackson to implement a serde in Confluent’s kafka-streams-examples repo. > > I’m not sure what other/better examples > > might be out there. > > > > Hope this helps, > > John > > > > On Thu, Nov 19, 2020, at 00:27, Eric Beabes wrote: > > > Not sure what you mean by "pass it explicitly". The definition of 'to' is > > > given below. Can we pass it explicitly in this case. If yes, can you > > please > > > show me how? > > > > > > def to(topic: String)(implicit produced: Produced[K, V]): Unit = > > > inner.to(topic, produced) > > > > > > > > > Also not sure how to use a self documenting format like JSON. Any > > > examples to share? > > > > > > > > > On Wed, Nov 18, 2020 at 5:14 PM John Roesler <vvcep...@apache.org> > > wrote: > > > > > > > Hi Eric, > > > > > > > > Ah, that’s a bummer. The correct serde is the session windowed serde, > > as I > > > > can see you know. I’m afraid I’m a bit rusty on implicit resolution > > rules, > > > > so I can’t be much help there. > > > > > > > > But my general recommendation for implicits is that when things get > > weird, > > > > just don’t use them at all. For example, you can just explicitly pass > > the > > > > Produced in the second arg list of ‘to’. > > > > > > > > One other tip is that the serialized form produced by those serdes is > > kind > > > > of specialized and might not be the most convenient for your use. If > > this > > > > is just a POC, if suggest mapping the keys to strings, so they are > > > > human-readable. If this is a production use case, then you might want > > to > > > > use a more self-documenting format like JSON or AVRO. Just my two > > cents. > > > > > > > > I hope this helps! > > > > -John > > > > > > > > On Wed, Nov 18, 2020, at 14:02, Eric Beabes wrote: > > > > > I keep getting '*ambiguous implicit values*' message in the following > > > > code. > > > > > I tried several things (as can be seen from a couple of lines I've > > > > > commented out). Any ideas on how to fix this? This is in *Scala*. > > > > > > > > > > def createTopology(conf: Config, properties: Properties): Topology = > > > > > {// implicit val sessionSerde = > > > > > Serde[WindowedSerdes.SessionWindowedSerde[String]]// implicit val > > > > > produced: Produced[Windowed[String], Long] = > > > > > Produced.`with`[WindowedSerdes.SessionWindowedSerde[String], Long] > > > > > implicit val produced: Produced[Windowed[String], Long] = > > > > > Produced.`with`[Windowed[String], Long] > > > > > implicit val consumed: Consumed[String, String] = > > > > > Consumed.`with`[String, String] > > > > > > > > > > val builder: StreamsBuilder = new StreamsBuilder() > > > > > builder.stream("streams-plaintext-input") > > > > > .groupBy((_, word) => word) > > > > > .windowedBy(SessionWindows.`with`(Duration.ofMillis(60 * > > 1000))) > > > > > .count() > > > > > .toStream.to("streams-pipe-output") > > > > > > > > > > builder.build() > > > > > > > > > > } > > > > > > > > > > *Compiler Errors:* > > > > > > > > > > Error:(52, 78) ambiguous implicit values: > > > > > both method timeWindowedSerde in object Serdes of type [T](implicit > > > > > tSerde: > > > > > > > > > > > org.apache.kafka.common.serialization.Serde[T])org.apache.kafka.streams.kstream.WindowedSerdes.TimeWindowedSerde[T] > > > > > and method sessionWindowedSerde in object Serdes of type > > [T](implicit > > > > > tSerde: > > > > > > > > > > > org.apache.kafka.common.serialization.Serde[T])org.apache.kafka.streams.kstream.WindowedSerdes.SessionWindowedSerde[T] > > > > > match expected type > > > > > > > > > > > org.apache.kafka.common.serialization.Serde[org.apache.kafka.streams.kstream.Windowed[String]] > > > > > implicit val produced: Produced[Windowed[String], Long] = > > > > > Produced.`with`[Windowed[String], Long] > > > > > Error:(52, 78) could not find implicit value for parameter keySerde: > > > > > > > > > > > org.apache.kafka.common.serialization.Serde[org.apache.kafka.streams.kstream.Windowed[String]] > > > > > implicit val produced: Produced[Windowed[String], Long] = > > > > > Produced.`with`[Windowed[String], Long] > > > > > Error:(52, 78) not enough arguments for method with: (implicit > > > > > keySerde: > > > > > > > > > > > org.apache.kafka.common.serialization.Serde[org.apache.kafka.streams.kstream.Windowed[String]], > > > > > implicit valueSerde: > > > > > > > > > > > org.apache.kafka.common.serialization.Serde[Long])org.apache.kafka.streams.kstream.Produced[org.apache.kafka.streams.kstream.Windowed[String],Long].Unspecified > > > > > value parameters keySerde, valueSerde. > > > > > implicit val produced: Produced[Windowed[String], Long] = > > > > > Produced.`with`[Windowed[String], Long] > > > > > > > > > > > > > > >
