(Happy to accept a PR. The relevant code is in `messageLoop()` and `RpcConnectionState::disconnect()` in `rpc.c++`.)
On Wed, Sep 27, 2023 at 2:05 PM Kenton Varda <ken...@cloudflare.com> wrote: > Indeed, there isn't really a clean shutdown mechanism right now. I guess > it hasn't come up as a priority because in most use cases we just haven't > really cared if there's a TCP RST triggered under the hood... since we're > already killing the connection, we ignore that error anyway. > > I suppose what we should do is, in the case that we receive a clean EOF, > inhibit the sending of an abort message back, just send EOF back. > > -Kenton > > On Thu, Sep 21, 2023 at 6:09 PM 'Alex' via Cap'n Proto < > capnproto@googlegroups.com> wrote: > >> Hi all, >> >> I am designing an application (in C++) where, upon invocation of a >> particular RPC call, both the server and the client agree to cleanly >> disconnect from one another. By "cleanly", I mean that both the server >> and the client send a TCP FIN/ACK and nothing more (e.g. no RSTs). >> Unfortunately, in the current design the receipt of a FIN will cause >> AsyncIoMessageStream::tryReadMessage() to abort, whereupon it will >> throw KJ_EXCEPTION(DISCONNECTED, "Peer disconnected.")[0]. This >> exception is eventually written to the client socket, and if the client >> is already gone, there will be one or more RSTs in response: >> >> C -> S: "Goodbye" (RPC call) >> C -> S: "I have nothing more to say" (TCP FIN) >> >> (the client does not expect the server to say anything more and closes >> the socket) >> >> S -> C: "Exception! You disconnected from me" (RPC message) >> C -> S: "Error: Connection reset by peer" (TCP RST) >> >> Given that both the server and client have agreed to shut down the >> connection, this is not an exceptional circumstance. Therefore, an >> exception should not be thrown. >> >> Unfortunately, there does not seem to be a way to indicate to the >> RpcSystem that the DISCONNECTED exception ought to be suppressed. Is >> there something I am missing? I appreciate any assistance. >> >> Regards, >> Alex >> >> [0] >> https://github.com/capnproto/capnproto/blob/761aeb17563a59f43b3fe9bae93df83c6bd57d06/c%2B%2B/src/capnp/rpc.c%2B%2B#L2775 >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Cap'n Proto" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to capnproto+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/capnproto/20230921190853.115b911d%40centromere.net >> . >> > -- You received this message because you are subscribed to the Google Groups "Cap'n Proto" group. To unsubscribe from this group and stop receiving emails from it, send an email to capnproto+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/capnproto/CAJouXQkvmFfnXVLR6M8itZeog4KrXLFXmaFiQw8ZxSxOfOyFMw%40mail.gmail.com.
