I have created https://issues.apache.org/jira/browse/KAFKA-759 to remove
versionId as discussed
On 2/13/13 7:40 PM, David Arthur wrote:
On 2/13/13 4:08 PM, Jay Kreps wrote:
Hey David,
We ended up not versioning the response, instead the version must
correspond to the request version.
This makes sense from the client point of view. If you send a request
using version X of the protocol you know you will get a response in
format X. Separately versioning the response would seem to indicate
that the server is allowed to send back a different version of the
response. This means the client has to check this and handle old
response versions (and what would it even do with newer versions?).
This makes complete sense. I was confused since OffsetCommit/Fetch are
including it in the responses
Instead we thought it makes more sense to make the server deal with
compatibility only. So the versioning is at the request/response pair
and the server is required to always send the correct version of the
response for all supported request versions.
I just noticed that your responses for the offset apis actually have a
version. We should probably remove that before the release.
Yea, agreed.
-Jay
On Wed, Feb 13, 2013 at 12:48 PM, David Arthur <mum...@gmail.com> wrote:
Just noticed that most of the API response structs do not include the
ApiVersion. This will make it hard for clients to determine how to
handle
responses once the APIs start getting updated (which is pretty much
inevitable).
I'd propose we update the standard response envelope to include it
Response => ApiVersion CorrelationId ResponseMessage
ApiVersion => int16
CorrelationId => int32
ResponseMessage => ...
Otherwise, it seems we must freeze the response formats forever.
Another thought is that the server should return the same version of
the API
that was requested (if a client sends in v1, then presumably it does
know
about any future versions...). How will this work? This seems to imply
backwards compat for the APIs like Avro.
Thoughts?
-David
