I think the challenge here is that even after KIP-35 clients will not know whether the server supports new sasl mechanisms or not, so non-Java clients will have to assume it is not supported (and will therefore lag behind on features).
I think this highlights a short-coming of KIP-35, and I'm wondering if there are good ways to address this. Gwen On Mon, Apr 4, 2016 at 12:05 PM, Jun Rao <j...@confluent.io> wrote: > I think with KIP-43, the existing way of sasl handshake during connection > still works. It's just that if you want to support non-GSSAPI, you will > need a new sasl handshake implementation in the client. It's unfortunate > that Protocol currently only covers the communication after the connection > is ready to use, but not during handshake. For now, we can probably just > document this change during handshake since changing the implementation is > optional. > > Thanks, > > Jun > > On Mon, Apr 4, 2016 at 11:28 AM, Gwen Shapira <g...@confluent.io> wrote: > > > Hi Kafka Team, > > > > As a practical test-case of KIP-35, I'd like to turn your attention to > > KIP-43: > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-43 > > > > KIP-43 makes an interesting modification to the protocol, but only under > > specific conditions: > > > > "*Client flow:* > > > > 1. If sasl.mechanism is not GSSAPI, send a packet with the mechanism > > name to the server. Otherwise go to Step 3. > > - Packet Format: | Version (Int16) | Mechanism (String) | > > 2. Wait for response from the server. If the error code in the > response > > is non-zero, indicating failure, report the error and fail > > authentication. > > 3. Perform SASL authentication with the configured client mechanism > > > > *Server flow:* > > > > 1. Wait for first authentication packet from client > > 2. If this packet is a not valid mechanism request, go to Step 4 and > > process this packet as the first GSSAPI client token > > 3. If the client mechanism received in Step 2 is enabled in the > broker, > > send a response with error code zero and start authentication using > the > > specified mechanism. Otherwise, send an error response including the > > list > > of enabled mechanisms and fail authentication. > > - Packet Format: | ErrorCode (Int16) | EnabledMechanisms > > (ArrayOf(String)) > > | > > 4. Perform SASL authentication with the selected mechanism. If > mechanism > > exchange was skipped, process the initial packet that was received > from > > the > > client first." > > > > > > I'd love to know how this will be communicated to clients via > > VersionRequest proposed in KIP-35 (mostly because Jun and I need to > review > > KIP-43 and we want to be sure we are not breaking the new protocol at the > > same time we introduce it) > > > > Do we: > > 1. Bump protocol version of every single Request? Even though unless you > > are using a new sasl mechanism nothing changes? > > 2. Ignore and not bump protocol? If so, how will clients know that new > > sasl.mechanisms are supported? > > 3. Something else? > > > > Gwen > > >
