runtime: HTTP2: Canceling token given to HttpClient.SendAsync does not send RST_STREAM

Found by a customer: https://twitter.com/stevejgordon/status/1169995743568048129

This is a high impact bug. A user will cancel a streaming gRPC call on the client, but the server will never be notified. If the server is checking CancellationToken.IsCancellationRequested then it will hang open forever.

This is a regression of https://github.com/dotnet/corefx/issues/38391

Repro:

git clone https://github.com/JamesNK/grpc-dotnet.git
git checkout jamesnk/duplex-cancellation-regression
dotnet test test\FunctionalTests --filter Name~ServerStreaming_CancellationOnClient_SentToServer

Logic in the test is something like:

Client makes a server streaming call to the server. This means the client is sending one message in the request’s HttpContent, which then completes.
Server streams multiple messages to the client
Client triggers the cancellation token given to gRPC client. HttpClient.SendAsync token is canceled
The HttpClient should be sending RST_STREAM to the server, and the server should report the call is canceled. This isn’t happening so the server will stream messages forever.

Wireshark log: cancellation-regression.zip

About this issue

Original URL
State: closed
Created 5 years ago
Comments: 20 (20 by maintainers)

Most upvoted comments

Confirmed disposing HttpResponseMessage works and no other gRPC unit tests regressed.

JamesNK on Sep 6, 2019

To echo what @stephentoub said: how is this different from existing tests we have, either for GRPC or HttpClient? We know that cancellation does send RST_STREAM for the tests we have, so what’s special about this?

geoffkizer on Sep 6, 2019

The repo in the original issue should re-create it. However it won’t compile against the latest .NET Core SDK because of breaking changes.

I’m writing a new regression test now.

JamesNK on Sep 6, 2019