Note also that once you get the Bytes in Python, you can use whatever coder (or Map) to decode them that you want.
On Thu, Jul 16, 2020 at 9:21 AM Boyuan Zhang <boyu...@google.com> wrote: > > Hi Piotr, > > X-Lang uses TypedWithoutMetadata, which outputs the KV directly instead of > KafkaRecord: see here. Given the limit that x-lang can only work with > well-known coders, if you want to process the KV in python output from > KafkaIO, the coders of key and value should be well-known in beam. By > default, the key and value are bytes: see here. > > On Thu, Jul 16, 2020 at 8:48 AM Piotr Szuberski <piotr.szuber...@polidea.com> > wrote: >> >> I'm writing a python wrappers for KinesisIO and I encountered a problem that >> Read transform creates a PCollection with KinesisRecord class which's coder >> by default is assigned as 'beam:coders:javasdk:0.1'. I managed to register >> this coder using CoderTranslatorRegistrar which adds the coder to the >> KNOWN_CODER_URNS and therefore is sent with my custom urn. >> >> Kafka's cross language Write transform uses KV<>, is encoded by default in >> beam. >> >> But I can't see how KafkaRecordCoder is translated in cross-language usage >> to python? I can't see any place in code where it gets registered. >> >> I just don't get how KafkaIO.Read works in cross-language. Could someone >> clarify me how does it work? >> >> Thanks in advance!
