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router: fixing a watermark bug for streaming retries #10866

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Merged
alyssawilk merged 3 commits into from
Apr 22, 2020
Merged

router: fixing a watermark bug for streaming retries #10866

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5a18a17
router: fixing a watermark bug with large bodies and retries
alyssawilk Apr 20, 2020
b7848eb
giving up on deflaking
alyssawilk Apr 21, 2020
e7bddd3
Merge branch 'master' into retry_with_overrun
alyssawilk Apr 21, 2020
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12 changes: 11 additions & 1 deletion source/common/router/upstream_request.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,12 @@ UpstreamRequest::~UpstreamRequest() {
upstream_log->log(parent_.downstreamHeaders(), upstream_headers_.get(),
upstream_trailers_.get(), stream_info_);
}

while (downstream_data_disabled_ != 0) {
parent_.callbacks()->onDecoderFilterBelowWriteBufferLowWatermark();
parent_.cluster()->stats().upstream_flow_control_drained_total_.inc();
--downstream_data_disabled_;
}
}

void UpstreamRequest::decode100ContinueHeaders(Http::ResponseHeaderMapPtr&& headers) {
Expand Down Expand Up @@ -421,7 +427,6 @@ void UpstreamRequest::DownstreamWatermarkManager::onAboveWriteBufferHighWatermar
// can disable reads from upstream.
ASSERT(!parent_.parent_.finalUpstreamRequest() ||
&parent_ == parent_.parent_.finalUpstreamRequest());

// The downstream connection is overrun. Pause reads from upstream.
// If there are multiple calls to readDisable either the codec (H2) or the underlying
// Network::Connection (H1) will handle reference counting.
Expand Down Expand Up @@ -451,6 +456,7 @@ void UpstreamRequest::disableDataFromDownstreamForFlowControl() {
ASSERT(parent_.upstreamRequests().size() == 1 || parent_.downstreamEndStream());
parent_.cluster()->stats().upstream_flow_control_backed_up_total_.inc();
parent_.callbacks()->onDecoderFilterAboveWriteBufferHighWatermark();
++downstream_data_disabled_;
}

void UpstreamRequest::enableDataFromDownstreamForFlowControl() {
Expand All @@ -466,6 +472,10 @@ void UpstreamRequest::enableDataFromDownstreamForFlowControl() {
ASSERT(parent_.upstreamRequests().size() == 1 || parent_.downstreamEndStream());
parent_.cluster()->stats().upstream_flow_control_drained_total_.inc();
parent_.callbacks()->onDecoderFilterBelowWriteBufferLowWatermark();
ASSERT(downstream_data_disabled_ != 0);
if (downstream_data_disabled_ > 0) {
--downstream_data_disabled_;
}
}

void HttpConnPool::newStream(GenericConnectionPoolCallbacks* callbacks) {
Expand Down
2 changes: 2 additions & 0 deletions source/common/router/upstream_request.h
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Original file line number Diff line number Diff line change
Expand Up @@ -159,6 +159,8 @@ class UpstreamRequest : public Logger::Loggable<Logger::Id::router>,
Http::ResponseTrailerMapPtr upstream_trailers_;
Http::MetadataMapVector downstream_metadata_map_vector_;

// Tracks the number of times the flow of data from downstream has been disabled.
uint32_t downstream_data_disabled_{};
bool calling_encode_headers_ : 1;
bool upstream_canary_ : 1;
bool decode_complete_ : 1;
Expand Down
32 changes: 28 additions & 4 deletions test/common/router/router_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -5674,9 +5674,10 @@ class WatermarkTest : public RouterTest {
.WillOnce(Return(std::chrono::milliseconds(0)));
EXPECT_CALL(callbacks_.dispatcher_, createTimer_(_)).Times(0);

EXPECT_CALL(stream_, addCallbacks(_)).WillOnce(Invoke([&](Http::StreamCallbacks& callbacks) {
stream_callbacks_ = &callbacks;
}));
EXPECT_CALL(stream_, addCallbacks(_))
.Times(num_add_callbacks_)
.WillOnce(
Invoke([&](Http::StreamCallbacks& callbacks) { stream_callbacks_ = &callbacks; }));
EXPECT_CALL(encoder_, getStream()).WillRepeatedly(ReturnRef(stream_));
EXPECT_CALL(cm_.conn_pool_, newStream(_, _))
.WillOnce(Invoke(
Expand Down Expand Up @@ -5707,6 +5708,7 @@ class WatermarkTest : public RouterTest {
Http::ResponseDecoder* response_decoder_ = nullptr;
Http::TestRequestHeaderMapImpl headers_;
Http::ConnectionPool::Callbacks* pool_callbacks_{nullptr};
int num_add_callbacks_{1};
};

TEST_F(WatermarkTest, DownstreamWatermarks) {
Expand Down Expand Up @@ -5786,7 +5788,29 @@ TEST_F(WatermarkTest, FilterWatermarks) {
.value());

sendResponse();
} // namespace Router
}

TEST_F(WatermarkTest, FilterWatermarksUnwound) {
num_add_callbacks_ = 0;
EXPECT_CALL(callbacks_, decoderBufferLimit()).Times(3).WillRepeatedly(Return(10));
router_.setDecoderFilterCallbacks(callbacks_);
// Send the headers sans-fin, and don't flag the pool as ready.
sendRequest(false, false);

// Send 11 bytes of body to fill the 10 byte buffer.
Buffer::OwnedImpl data("1234567890!");
router_.decodeData(data, false);
EXPECT_EQ(1U, cm_.thread_local_cluster_.cluster_.info_->stats_store_
.counter("upstream_flow_control_backed_up_total")
.value());

// Set up a pool failure, and make sure the flow control blockage is undone.
pool_callbacks_->onPoolFailure(Http::ConnectionPool::PoolFailureReason::RemoteConnectionFailure,
absl::string_view(), nullptr);
EXPECT_EQ(1U, cm_.thread_local_cluster_.cluster_.info_->stats_store_
.counter("upstream_flow_control_drained_total")
.value());
}

// Same as RetryRequestNotComplete but with decodeData larger than the buffer
// limit, no retry will occur.
Expand Down