Fix hibernatable websocket race between auto-response and regular messages #1130
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changed the title
src/workerd/api/web-socket.c++
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| @@ -531,7 +531,10 @@ void WebSocket::send(jsg::Lock& js, kj::OneOf<kj::Array<byte>, kj::String> messa | |||
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| KJ_UNREACHABLE; | |||
| }(); | |||
| outgoingMessages->insert(GatedMessage{kj::mv(maybeOutputLock), kj::mv(msg)}); | |||
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| auto n = autoResponseStatus.pendingAutoResponseQueue.size() - autoResponseStatus.queuedAutoResponses; | |||
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Can you explain the difference between GatedMessage::pendingAutoResponses, and AutoResponse::queuedAutoResponses?
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GatedMessage::pendingAutoResponses stores the number of AutoResponse::queuedAutoResponses that will be pumped before sending the current GatedMessage, guaranteeing order. AutoResponse::queuedAutoResponses stores the total number of already queued pendingAutoResponses, so we can check how many are yet to be added during each GateMessage instantiation.
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@jasnell can I get another pair of eyes reviewing this PR if you have time? |
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| // Keep track of current hibernatable websockets auto-response status to avoid racing | ||
| // between regular websocket messages, and auto-responses. | ||
| struct AutoResponse { | ||
| kj::Promise<void> ongoingAutoResponse = kj::READY_NOW; |
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Ahhhh, so I think what I was expecting was that outgoingAutoResponse would be a forked promise ala:
kj::Promise<void> ongoingAutoResponse = kj::Proimse<void>(kj::READY_NOW).fork();
I think what you have here works, it's just a touch unusual! I'm guessing it was hard to phrase sendAutoResponse() in that context.
This PR fixes possible racing issues between regular websocket messages and auto-responses.
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This PR fixes possible
ws.sendraces between auto-response messages and regular web sockets.