Close channel during upgrade, if client closes input #2756
Conversation
| switch event { | ||
| case let evt as ChannelEvent where evt == ChannelEvent.inputClosed: | ||
| // The remote peer half-closed the channel during the upgrade so we should close | ||
| context.close(promise: nil) |
There was a problem hiding this comment.
Thanks for working on this!
Can we please go through the state machine here. In particular, if we are in the state unbuffering we should not close here but rather just hold the event until the unbuffering is done.
Can we also write a test for this and look if we need to do the same for the client upgrade handler?
There was a problem hiding this comment.
We should also consider only closing if we haven't received a full upgrade request, and otherwise we should buffer this.
There was a problem hiding this comment.
I did consider this case, but thought I would post this first to start the conversation. So should we only close the connection if we are in the state initial and awaitingUpgrader. Otherwise should I let it run until the upgrade is complete?
Second all the upgrade tests use EmbeddedChannel. Is it possible to emulate half closure with EmbeddedChannel?
There was a problem hiding this comment.
It should be possible to emulate half closure with the embedded channel by just sending the event to the channel.
Lukasa
added
the
patch-version-bump-only
I had to add another handler to `setUpTestWithAutoremoval` to catch upgrade errors.
| @inlinable | ||
| mutating func closeInbound() -> CloseInboundAction { | ||
| switch self.state { | ||
| case .initial, .awaitingUpgrader: |
There was a problem hiding this comment.
We should immediately close in the state initial. In the state awaitingUpgrader we have to check if we have seenFirstRequest == true. If have seen that we should buffer the inputClosed and send it after the upgrading is finished. In the state upgraderReady we need to buffer the inputClosed indefinitely.
The reason why this is so complicated is that the client could potentially send a half closure after it send the initial upgrade request + some data on the upgraded protocol. We can't just unconditionally close here but we rather need to buffer the inputClose and unbuffer it with the data. I would recommend changing the var buffer: Deque<NIOAny> in the various states to var buffer: Deque<enum(NIOAny | inputClosed)>.
| self.state = .finished | ||
| return .close | ||
|
|
||
| default: |
There was a problem hiding this comment.
Can we please spell out all cases explicitly so if we ever add one we get a compiler error here
Check for half closure during server upgrade and close channel if client closes the channel
Motivation:
This is to fix #2742
Modifications:
Add
userInboundEventTriggeredfunction toNIOTypedHTTPServerProtocolUpgraderwhich checks forChannelEvent.inputClosedResult:
Negotiation future now errors when client closes the connection instead of never completing