Hi,
I'm automating a low level C# kafka protocol definition by parsing the
Kafka protocol guide (inkl the Record Batch documentation), and I've
found some inconsistencies in the protocol guide:
1. Common Request and Response Structure
RequestOrResponse => Size (RequestMessage | ResponseMessage)
Size => int32
FIELD DESCRIPTION
message_size The message_size field gives the size of the subsequent
request or response message in bytes. The client can read requests by
first reading this 4 byte size as an integer N, and then reading and
parsing the subsequent N bytes of the request.
* int32 does not follow the primitive type name INT32
* RequestMessage and ResponseMessage is never defined
* message_size is not an expression. Correct name should be Size
2. Inconsistent usage of ARRAY expressions.
Sometimes an array is expressed as a field surrounded with brackets,
i.e. [topics] and sometimes it is expresses as ARRAY(INT32). Brackets in
BNF usually indicates that the term is optional, which makes the usage
of brackets in the context of an array confusing. Parenthesis is a
grouping expression, so that is also confusing. Why not skip the use of
an ARRAY primitive type and instead use a repetition expression in BNF,
like the following example?
|Metadata Request (Version: 1) => topics topics => INT32 topic* topic =>
STRING |
3. Record batch documentation
Would it not be nice to use the BNFÂ format here as well? It is being
used under the "5.3.3 Old Message Format" but not for "5.3.1 Record
Batch" and "5.3.2 Record".
Best regards
//Fredrik
