Hey Yaroslav!,

I suppose I will try it like this. The lookup would indeed be nice too, I will 
have a closer look at the corresponding source code. Thanks!

-Theo
> On 29. Nov 2022, at 17:41, Yaroslav Tkachenko <yaros...@goldsky.com> wrote:
> 
> Hey Theodor,
> 
> That's pretty much it, assuming your Protobuf schema is more or less fixed. 
> But for a production workload, you'd need to add a Schema Registry lookup. I 
> guess the implementation for that would be similar to what's in the Avro 
> format.
> 
> On Tue, Nov 29, 2022 at 2:26 AM Theodor Wübker <theo.wueb...@inside-m2m.de 
> <mailto:theo.wueb...@inside-m2m.de>> wrote:
> Hey all,
> 
> so Confluent has Kafka serializers to serialize Protobuf, Avro and JSON that 
> create messages with a magic byte followed by a 4 byte schema id followed by 
> the actual payload (refer the docs 
> <https://docs.confluent.io/platform/current/schema-registry/serdes-develop/index.html#wire-format>).
>  When I try to read such messages with the regular Protobuf, Avro and JSON 
> formats in my Table API Program, it of course does not work. For Avro, Flink 
> also has a Confluent-Avro format that can deal with this. However for 
> Protobuf and JSON, there is nothing like this yet. I saw a ticket in the JIRA 
> <https://issues.apache.org/jira/browse/FLINK-29731?filter=-4&jql=project%20=%20FLINK%20AND%20issuetype%20=%20%22New%20Feature%22%20AND%20text%20~%20%22protobuf%22%20order%20by%20created%20DESC>,
>  but I cannot wait for this. Hence I wonder, how much effort it would be, to 
> implement this myself - not in a production-ready way, but just in a way that 
> makes my program not break. Meaning I would be happy with a solution that 
> just ignores the first 5 bytes and passes the rest on to the existing 
> handlers of Protobuf and JSON formats.
> 
> 
> Now lets take for Example the existing Protobuf Format: I assume I have to 
> implement the DeserializationFormatFactory, create a few Decoding and 
> Encoding Formats, just like the PbDecodingFormat for example, then a new 
> DeserializationSchema and there I would have such a method 
> <https://nightlies.apache.org/flink/flink-docs-master/api/java/org/apache/flink/formats/protobuf/deserialize/PbRowDataDeserializationSchema.html>:
> 
> @Override
> public RowData deserialize(byte[] message) throws IOException {
>     try {
>         return protoToRowConverter.convertProtoBinaryToRow(message);
>     } catch (Throwable t) {
>         if (formatConfig.isIgnoreParseErrors()) {
>             return null;
>         }
>         throw new IOException("Failed to deserialize PB object.", t);
>     }
> }
> But instead of converting the message immediately, I would slice the first 
> few Bytes off and go from there. Is this pretty much it, or is there more to 
> it?
> 
> -Theo
> 

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