Insert data from message header (or key) to clickhouse

[ne1r0n]

I have a case where kafka topic contains some useful information inside message header and I would like to ingest that data to ClickHouse together with value.

I've tried to use HeaderToField and HeaderToValue transforms, but it doesn't work with json w/o schemas.

I would be great if ClickHouse kafka connect could read and insert data from header and key into ClickHouse.
For the header to put a json with header's key/value into a one column would be more than enough or it could be a mapping in connect config to get exact key and put it to desired column.

[Paultagoras]

I have an idea for this @ne1r0n - let me take a stab at it and let you know...

We've already created a Single Message Transform for something else - it might make sense to use that here.

[ne1r0n]

The problem is 2 mentioned above SMTs don't work with schema-less json.