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router: inject tracing context in the upstream request #20503

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Merged
mattklein123 merged 2 commits into from
Mar 28, 2022
Merged

router: inject tracing context in the upstream request #20503

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router: inject tracing context in the upstream request
wbpcode Mar 24, 2022
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wbpcode Mar 26, 2022
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3 changes: 0 additions & 3 deletions source/common/router/router.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -652,9 +652,6 @@ Http::FilterHeadersStatus Filter::decodeHeaders(Http::RequestHeaderMap& headers,
}
callbacks_->streamInfo().setAttemptCount(attempt_count_);

// Inject the active span's tracing context into the request headers.
callbacks_->activeSpan().injectContext(headers);
Comment on lines -655 to -656
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@mattklein123 mattklein123 Mar 24, 2022

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What are the implications of this with regard to retries and hedging? I'm concerned this a change in behavior here?

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@wbpcode wbpcode Mar 25, 2022

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If start_child_span is set to false, then we may do some repeated injectings when retries occur. This should be safe because in previous implementation, we may re-inject tracing context as well.

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@wbpcode wbpcode Mar 25, 2022

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In the #20367, we want to update the injectContext API to add a new parameter to provide target upstream of current upstream request. This PR can also complete some pre-work.


route_entry_->finalizeRequestHeaders(headers, callbacks_->streamInfo(),
!config_.suppress_envoy_headers_);
FilterUtility::setUpstreamScheme(
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5 changes: 5 additions & 0 deletions source/common/router/upstream_request.cc
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Expand Up @@ -486,6 +486,11 @@ void UpstreamRequest::onPoolReady(

if (span_ != nullptr) {
span_->injectContext(*parent_.downstreamHeaders());
} else {
// No independent child span for current upstream request then inject the parent span's tracing
// context into the request headers.
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@mattklein123 mattklein123 Mar 25, 2022

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OK I understand now, thanks for explaining. Do you mind adding a few more comments here on the implications of doing this multiple times for retries, etc.? I understand this is the way it was always done, but it's a little more confusing now. Thank you!

/wait

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@wbpcode wbpcode Mar 26, 2022

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get it.

// The injectContext() of the parent span may be called repeatedly when the request is retried.
parent_.callbacks()->activeSpan().injectContext(*parent_.downstreamHeaders());
}

upstreamTiming().onFirstUpstreamTxByteSent(parent_.callbacks()->dispatcher().timeSource());
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37 changes: 37 additions & 0 deletions test/common/router/router_2_test.cc
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Expand Up @@ -532,6 +532,43 @@ TEST_F(RouterTestChildSpan, ResetRetryFlow) {
response_decoder->decodeHeaders(std::move(response_headers), true);
}

class RouterTestNoChildSpan : public RouterTestBase {
public:
RouterTestNoChildSpan()
: RouterTestBase(false, false, false, Protobuf::RepeatedPtrField<std::string>{}) {}
};

TEST_F(RouterTestNoChildSpan, BasicFlow) {
EXPECT_CALL(callbacks_.route_->route_entry_, timeout())
.WillOnce(Return(std::chrono::milliseconds(0)));
EXPECT_CALL(callbacks_.dispatcher_, createTimer_(_)).Times(0);

NiceMock<Http::MockRequestEncoder> encoder;
Http::ResponseDecoder* response_decoder = nullptr;
EXPECT_CALL(cm_.thread_local_cluster_.conn_pool_, newStream(_, _, _))
.WillOnce(
Invoke([&](Http::ResponseDecoder& decoder, Http::ConnectionPool::Callbacks& callbacks,
const Http::ConnectionPool::Instance::StreamOptions&)
-> Http::ConnectionPool::Cancellable* {
response_decoder = &decoder;
EXPECT_CALL(callbacks_.active_span_, injectContext(_));
callbacks.onPoolReady(encoder, cm_.thread_local_cluster_.conn_pool_.host_,
upstream_stream_info_, Http::Protocol::Http10);
return nullptr;
}));

Http::TestRequestHeaderMapImpl headers;
HttpTestUtility::addDefaultHeaders(headers);
router_.decodeHeaders(headers, true);
EXPECT_EQ(1U,
callbacks_.route_->route_entry_.virtual_cluster_.stats().upstream_rq_total_.value());

Http::ResponseHeaderMapPtr response_headers(
new Http::TestResponseHeaderMapImpl{{":status", "200"}});
ASSERT(response_decoder);
response_decoder->decodeHeaders(std::move(response_headers), true);
}

namespace {

Protobuf::RepeatedPtrField<std::string> protobufStrList(const std::vector<std::string>& v) {
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7 changes: 0 additions & 7 deletions test/common/router/router_test.cc
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Expand Up @@ -412,7 +412,6 @@ TEST_F(RouterTest, Http1Upstream) {
Http::TestRequestHeaderMapImpl headers;
HttpTestUtility::addDefaultHeaders(headers);
EXPECT_CALL(callbacks_.route_->route_entry_, finalizeRequestHeaders(_, _, true));
EXPECT_CALL(span_, injectContext(_));
router_.decodeHeaders(headers, true);
EXPECT_EQ("10", headers.get_("x-envoy-expected-rq-timeout-ms"));

Expand All @@ -432,7 +431,6 @@ TEST_F(RouterTest, Http2Upstream) {

Http::TestRequestHeaderMapImpl headers;
HttpTestUtility::addDefaultHeaders(headers);
EXPECT_CALL(span_, injectContext(_));
router_.decodeHeaders(headers, true);

// When the router filter gets reset we should cancel the pool request.
Expand Down Expand Up @@ -739,7 +737,6 @@ TEST_F(RouterTest, MaintenanceMode) {
EXPECT_CALL(callbacks_, encodeHeaders_(HeaderMapEqualRef(&response_headers), false));
EXPECT_CALL(callbacks_, encodeData(_, true));
EXPECT_CALL(callbacks_.stream_info_, setResponseFlag(StreamInfo::ResponseFlag::UpstreamOverflow));
EXPECT_CALL(span_, injectContext(_)).Times(0);

Http::TestRequestHeaderMapImpl headers;
HttpTestUtility::addDefaultHeaders(headers);
Expand Down Expand Up @@ -4556,7 +4553,6 @@ TEST_F(RouterTest, DirectResponse) {

Http::TestResponseHeaderMapImpl response_headers{{":status", "200"}};
EXPECT_CALL(callbacks_, encodeHeaders_(HeaderMapEqualRef(&response_headers), true));
EXPECT_CALL(span_, injectContext(_)).Times(0);
Http::TestRequestHeaderMapImpl headers;
HttpTestUtility::addDefaultHeaders(headers);
router_.decodeHeaders(headers, true);
Expand Down Expand Up @@ -4606,7 +4602,6 @@ TEST_F(RouterTest, DirectResponseWithLocation) {
Http::TestResponseHeaderMapImpl response_headers{{":status", "201"},
{"location", "http://host/"}};
EXPECT_CALL(callbacks_, encodeHeaders_(HeaderMapEqualRef(&response_headers), true));
EXPECT_CALL(span_, injectContext(_)).Times(0);
Http::TestRequestHeaderMapImpl headers;
HttpTestUtility::addDefaultHeaders(headers);
router_.decodeHeaders(headers, true);
Expand All @@ -4630,7 +4625,6 @@ TEST_F(RouterTest, DirectResponseWithoutLocation) {

Http::TestResponseHeaderMapImpl response_headers{{":status", "200"}};
EXPECT_CALL(callbacks_, encodeHeaders_(HeaderMapEqualRef(&response_headers), true));
EXPECT_CALL(span_, injectContext(_)).Times(0);
Http::TestRequestHeaderMapImpl headers;
HttpTestUtility::addDefaultHeaders(headers);
router_.decodeHeaders(headers, true);
Expand Down Expand Up @@ -5653,7 +5647,6 @@ TEST_F(RouterTest, ApplicationProtocols) {

Http::TestRequestHeaderMapImpl headers;
HttpTestUtility::addDefaultHeaders(headers);
EXPECT_CALL(span_, injectContext(_));
router_.decodeHeaders(headers, true);

// When the router filter gets reset we should cancel the pool request.
Expand Down