netty: improve server handling of writes to reset streams (#10258)

* netty: improve server handling of writes to reset streams

A server stream can be reset by the client while server writes are still queued. After the stream is reset, the netty connection will forget the stream object. The `NettyServerHandler` must deal with that situation. `sendResponseHandlers` already had some code to do that. This change standardizes that code and adds it to `sendGrpcFrame`. This fixes a potential bug where a `SendGrpcFrameCommand` with `endOfStream=true` would raise an `AssertionError` if written to a reset stream. (This bug is not currently reachable because `endOfStream=false` for all server `SendGrpcFrameCommand` objects.)

* Do not call into the encoder when we know the stream is gone.
This commit is contained in:
Benjamin Peterson 2024-02-16 11:08:09 -08:00 committed by GitHub
parent 2f025b2b24
commit a68399a9b6
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1 changed files with 34 additions and 24 deletions

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@ -678,9 +678,7 @@ class NettyServerHandler extends AbstractNettyHandler {
return serverWriteQueue;
}
/**
* Handler for commands sent from the stream.
*/
/** Handler for commands sent from the stream. */
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
throws Exception {
@ -720,31 +718,45 @@ class NettyServerHandler extends AbstractNettyHandler {
}
}
private void closeStreamWhenDone(ChannelPromise promise, int streamId) throws Http2Exception {
final NettyServerStream.TransportState stream = serverStream(requireHttp2Stream(streamId));
if (stream != null) {
promise.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
stream.complete();
}
});
}
private void closeStreamWhenDone(ChannelPromise promise, Http2Stream stream) {
promise.addListener(
new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
serverStream(stream).complete();
}
});
}
/**
* Sends the given gRPC frame to the client.
*/
private void sendGrpcFrame(ChannelHandlerContext ctx, SendGrpcFrameCommand cmd,
ChannelPromise promise) throws Http2Exception {
private static void streamGone(int streamId, ChannelPromise promise) {
promise.setFailure(
new IllegalStateException(
"attempting to write to stream " + streamId + " that no longer exists") {
@Override
public synchronized Throwable fillInStackTrace() {
return this;
}
});
}
/** Sends the given gRPC frame to the client. */
private void sendGrpcFrame(
ChannelHandlerContext ctx, SendGrpcFrameCommand cmd, ChannelPromise promise)
throws Http2Exception {
try (TaskCloseable ignore = PerfMark.traceTask("NettyServerHandler.sendGrpcFrame")) {
PerfMark.attachTag(cmd.stream().tag());
PerfMark.linkIn(cmd.getLink());
int streamId = cmd.stream().id();
Http2Stream stream = connection().stream(streamId);
if (stream == null) {
streamGone(streamId, promise);
return;
}
if (cmd.endStream()) {
closeStreamWhenDone(promise, cmd.stream().id());
closeStreamWhenDone(promise, stream);
}
// Call the base class to write the HTTP/2 DATA frame.
encoder().writeData(ctx, cmd.stream().id(), cmd.content(), 0, cmd.endStream(), promise);
encoder().writeData(ctx, streamId, cmd.content(), 0, cmd.endStream(), promise);
}
}
@ -756,16 +768,14 @@ class NettyServerHandler extends AbstractNettyHandler {
try (TaskCloseable ignore = PerfMark.traceTask("NettyServerHandler.sendResponseHeaders")) {
PerfMark.attachTag(cmd.stream().tag());
PerfMark.linkIn(cmd.getLink());
// TODO(carl-mastrangelo): remove this check once https://github.com/netty/netty/issues/6296
// is fixed.
int streamId = cmd.stream().id();
Http2Stream stream = connection().stream(streamId);
if (stream == null) {
resetStream(ctx, streamId, Http2Error.CANCEL.code(), promise);
streamGone(streamId, promise);
return;
}
if (cmd.endOfStream()) {
closeStreamWhenDone(promise, streamId);
closeStreamWhenDone(promise, stream);
}
encoder().writeHeaders(ctx, streamId, cmd.headers(), 0, cmd.endOfStream(), promise);
}