Yes, that e2e is probably not going to do nasty things. But it worth a try On Sun, Sep 17, 2023, 03:26 Valters Jansons <[email protected]> wrote:
> On Sat, Sep 16, 2023 at 10:02 PM Илья Шипицин <[email protected]> > wrote: > > I wonder if there're gRPC test tests similar to h2spec (I couldn't findI > am them) > > I am not aware of a single binary that could be used as a gRPC test > for proxies. The closest thing that I can think of is examples from > official gRPC libraries. Internally, the Go library runs a Bash script > for CI "Run extra tests" to check the outputs of examples. It can be > seen at > https://github.com/grpc/grpc-go/blob/v1.58.1/examples/examples_test.sh > and could be adopted for HAProxy, by overriding the client `-addr` > flag. There are no guarantees that it continues being maintained in > the current format though. > > --- > > But, gRPC is essentially a framework (binary encoding and custom > headers) for object-oriented HTTP/2. My observed issue is an HTTP/2 > processing issue by HAProxy, when the frontend client doesn't send an > END_STREAM flag. > > When I implement a similar scenario in other languages, the failure > rate is much lower. For example, I pushed a custom Java client to > https://github.com/sigv/grpcopen/tree/main/java that I was testing > with nginx (same HAProxy configuration as my other proof). When this > request succeeds, however, the session state is reported SD--. The > gRPC example to me is simply the most reliable failure, as there is > some timing involved, which I can't seem to yet figure out fully. > > To highlight H2 standard (RFC7540), section 8.1 states "the last frame > in the sequence bears an END_STREAM flag". It is however never > clarified if that's a "MUST" or a "SHOULD". The client could be argued > as non-compliant, assuming it is intended as "MUST". Maybe this is the > reason why the h2spec project does not cover such a scenario ("who > would do such a thing"). > > What is even more important for this issue though, is the last > paragraph of the same section: > > An HTTP response is complete after the server sends -- or the client > receives -- a frame with the END_STREAM flag set (including any > CONTINUATION frames needed to complete a header block). A server can > send a complete response prior to the client sending an entire > request if the response does not depend on any portion of the request > that has not been sent and received. When this is true, a server MAY > request that the client abort transmission of a request without error > by sending a RST_STREAM with an error code of NO_ERROR after sending > a complete response (i.e., a frame with the END_STREAM flag). > Clients MUST NOT discard responses as a result of receiving such a > RST_STREAM, though clients can always discard responses at their > discretion for other reasons. > > To paraphrase, when the backend server sends END_STREAM, the response > is complete and the server is not interested in the request data > anymore. The END_STREAM is a success in the eyes of the H2 spec, and > "clients MUST NOT discard responses as a result" (that is - HAProxy is > expected to send the response to client when END_STREAM). HAProxy > should not treat it as an abrupt close. When the backend server sends > RST_STREAM(NO_ERROR) to abort the connection, HAProxy must simply stop > sending data to the backend server. > > I understand there is some complexity with the mux, and tieing H1 into > it. But the H2 spec says the exchange is successful, and the observed > half-close is okay. > > Best regards, > Valters Jansons >
