We ran into similar difficulties, both when trying to get Kafka to use new APIs when available and when testing the wire protocol.
+1 for all three suggestions. #1 sounds like the bare minimum, but I'm not sure how much it will complicate the clients (now we expect either a response or an Unknown message and need to be able to distinguish between them from the byte array). #2 and #3 both makes lots of sense. Gwen On Mon, Jan 12, 2015 at 1:15 PM, Dana Powers <dana.pow...@rd.io> wrote: > Hi all -- continuing on the compatibility discussion: > > I've found that it is very difficult to identify when a server does not > recognize an api > (I'm using kafka-python to submit wire-protocol requests). For example, > when I > send a ConsumerMetadataRequest to an 0.8.1.1 server, I get a closed socket > *[stacktrace below]. The server raises an error internally, but does not > send any > meaningful response. I'm not sure whether this is the intended behavior, > but > maintaining clients in an ecosystem of multiple server versions with > different API > support it would be great to have a way to determine what the server > supports > and what it does not. > > Some suggestions: > > (1) An UnknownAPIResponse that is returned for any API or API Version > request > that is unsupported. > > (2) A server metadata API to get the list of supported APIs and/or API > versions supported. > > (3) A server metadata API to get the published version of the server (0.8.2 > v. 0.8.1.1, etc). > > > Thoughts? > > > Dana Powers > Rdio, Inc. > dana.pow...@rd.io > rdio.com/people/dpkp/ > > *stacktrace: > ``` > [2015-01-12 13:03:55,719] ERROR Closing socket for /127.0.0.1 because of > error (kafka.network.Processor) > kafka.common.KafkaException: Wrong request type 10 > at kafka.api.RequestKeys$.deserializerForKey(RequestKeys.scala:57) > at kafka.network.RequestChannel$Request.<init>(RequestChannel.scala:53) > at kafka.network.Processor.read(SocketServer.scala:353) > at kafka.network.Processor.run(SocketServer.scala:245) > at java.lang.Thread.run(Thread.java:722) > ```
