Merge pull request #23539 from donnadionne/fix

Adding Fake headers and ignored headers for header matching

src/core/ext/filters/client_channel/lb_policy/xds/xds_routing.cc

@@ -264,8 +264,19 @@ bool HeaderMatchHelper(
     const XdsApi::RdsUpdate::RdsRoute::Matchers::HeaderMatcher& header_matcher,
     LoadBalancingPolicy::MetadataInterface* initial_metadata) {
   std::string concatenated_value;
-  auto value = GetMetadataValue(header_matcher.name, initial_metadata,
-                                &concatenated_value);
+  absl::optional<absl::string_view> value;
+  // Note: If we ever allow binary headers here, we still need to
+  // special-case ignore "grpc-tags-bin" and "grpc-trace-bin", since
+  // they are not visible to the LB policy in grpc-go.
+  if (absl::EndsWith(header_matcher.name, "-bin") ||
+      header_matcher.name == "grpc-previous-rpc-attempts") {
+    value = absl::nullopt;
+  } else if (header_matcher.name == "content-type") {
+    value = "application/grpc";
+  } else {
+    value = GetMetadataValue(header_matcher.name, initial_metadata,
+                             &concatenated_value);
+  }
   if (!value.has_value()) {
     if (header_matcher.type == XdsApi::RdsUpdate::RdsRoute::Matchers::
                                    HeaderMatcher::HeaderMatcherType::PRESENT) {

test/cpp/end2end/xds_end2end_test.cc

@@ -3477,6 +3477,116 @@ TEST_P(LdsRdsTest, XdsRoutingHeadersMatching) {
   EXPECT_EQ(response_state.state, AdsServiceImpl::ResponseState::ACKED);
 }
 
+TEST_P(LdsRdsTest, XdsRoutingHeadersMatchingSpecialHeaderContentType) {
+  const char* kNewCluster1Name = "new_cluster_1";
+  const size_t kNumEchoRpcs = 100;
+  SetNextResolution({});
+  SetNextResolutionForLbChannelAllBalancers();
+  // Populate new EDS resources.
+  AdsServiceImpl::EdsResourceArgs args({
+      {"locality0", GetBackendPorts(0, 1)},
+  });
+  AdsServiceImpl::EdsResourceArgs args1({
+      {"locality0", GetBackendPorts(1, 2)},
+  });
+  balancers_[0]->ads_service()->SetEdsResource(
+      AdsServiceImpl::BuildEdsResource(args));
+  balancers_[0]->ads_service()->SetEdsResource(
+      AdsServiceImpl::BuildEdsResource(args1, kNewCluster1Name));
+  // Populate new CDS resources.
+  Cluster new_cluster1 = balancers_[0]->ads_service()->default_cluster();
+  new_cluster1.set_name(kNewCluster1Name);
+  balancers_[0]->ads_service()->SetCdsResource(new_cluster1);
+  // Populating Route Configurations for LDS.
+  RouteConfiguration route_config =
+      balancers_[0]->ads_service()->default_route_config();
+  auto* route1 = route_config.mutable_virtual_hosts(0)->mutable_routes(0);
+  route1->mutable_match()->set_prefix("");
+  auto* header_matcher1 = route1->mutable_match()->add_headers();
+  header_matcher1->set_name("content-type");
+  header_matcher1->set_exact_match("notapplication/grpc");
+  route1->mutable_route()->set_cluster(kNewCluster1Name);
+  auto* default_route = route_config.mutable_virtual_hosts(0)->add_routes();
+  default_route->mutable_match()->set_prefix("");
+  auto* header_matcher2 = default_route->mutable_match()->add_headers();
+  header_matcher2->set_name("content-type");
+  header_matcher2->set_exact_match("application/grpc");
+  default_route->mutable_route()->set_cluster(kDefaultResourceName);
+  SetRouteConfiguration(0, route_config);
+  // Make sure the backend is up.
+  WaitForAllBackends(0, 1);
+  // Send RPCs.
+  CheckRpcSendOk(kNumEchoRpcs);
+  EXPECT_EQ(kNumEchoRpcs, backends_[0]->backend_service()->request_count());
+  EXPECT_EQ(0, backends_[1]->backend_service()->request_count());
+  const auto& response_state = RouteConfigurationResponseState(0);
+  EXPECT_EQ(response_state.state, AdsServiceImpl::ResponseState::ACKED);
+}
+
+TEST_P(LdsRdsTest, XdsRoutingHeadersMatchingSpecialCasesToIgnore) {
+  const char* kNewCluster1Name = "new_cluster_1";
+  const char* kNewCluster2Name = "new_cluster_2";
+  const size_t kNumEchoRpcs = 100;
+  SetNextResolution({});
+  SetNextResolutionForLbChannelAllBalancers();
+  // Populate new EDS resources.
+  AdsServiceImpl::EdsResourceArgs args({
+      {"locality0", GetBackendPorts(0, 1)},
+  });
+  AdsServiceImpl::EdsResourceArgs args1({
+      {"locality0", GetBackendPorts(1, 2)},
+  });
+  AdsServiceImpl::EdsResourceArgs args2({
+      {"locality0", GetBackendPorts(2, 3)},
+  });
+  balancers_[0]->ads_service()->SetEdsResource(
+      AdsServiceImpl::BuildEdsResource(args));
+  balancers_[0]->ads_service()->SetEdsResource(
+      AdsServiceImpl::BuildEdsResource(args1, kNewCluster1Name));
+  balancers_[0]->ads_service()->SetEdsResource(
+      AdsServiceImpl::BuildEdsResource(args2, kNewCluster2Name));
+  // Populate new CDS resources.
+  Cluster new_cluster1 = balancers_[0]->ads_service()->default_cluster();
+  new_cluster1.set_name(kNewCluster1Name);
+  balancers_[0]->ads_service()->SetCdsResource(new_cluster1);
+  Cluster new_cluster2 = balancers_[0]->ads_service()->default_cluster();
+  new_cluster2.set_name(kNewCluster2Name);
+  balancers_[0]->ads_service()->SetCdsResource(new_cluster2);
+  // Populating Route Configurations for LDS.
+  RouteConfiguration route_config =
+      balancers_[0]->ads_service()->default_route_config();
+  auto* route1 = route_config.mutable_virtual_hosts(0)->mutable_routes(0);
+  route1->mutable_match()->set_prefix("");
+  auto* header_matcher1 = route1->mutable_match()->add_headers();
+  header_matcher1->set_name("grpc-foo-bin");
+  header_matcher1->set_present_match(true);
+  route1->mutable_route()->set_cluster(kNewCluster1Name);
+  auto route2 = route_config.mutable_virtual_hosts(0)->add_routes();
+  route2->mutable_match()->set_prefix("");
+  auto* header_matcher2 = route2->mutable_match()->add_headers();
+  header_matcher2->set_name("grpc-previous-rpc-attempts");
+  header_matcher2->set_present_match(true);
+  route2->mutable_route()->set_cluster(kNewCluster2Name);
+  auto* default_route = route_config.mutable_virtual_hosts(0)->add_routes();
+  default_route->mutable_match()->set_prefix("");
+  default_route->mutable_route()->set_cluster(kDefaultResourceName);
+  SetRouteConfiguration(0, route_config);
+  // Send headers which will mismatch each route
+  std::vector<std::pair<std::string, std::string>> metadata = {
+      {"grpc-foo-bin", "grpc-foo-bin"},
+      {"grpc-previous-rpc-attempts", "grpc-previous-rpc-attempts"},
+  };
+  WaitForAllBackends(0, 1);
+  CheckRpcSendOk(kNumEchoRpcs, RpcOptions().set_metadata(metadata));
+  // Verify that only the default backend got RPCs since all previous routes
+  // were mismatched.
+  EXPECT_EQ(kNumEchoRpcs, backends_[0]->backend_service()->request_count());
+  EXPECT_EQ(0, backends_[1]->backend_service()->request_count());
+  EXPECT_EQ(0, backends_[2]->backend_service()->request_count());
+  const auto& response_state = RouteConfigurationResponseState(0);
+  EXPECT_EQ(response_state.state, AdsServiceImpl::ResponseState::ACKED);
+}
+
 TEST_P(LdsRdsTest, XdsRoutingRuntimeFractionMatching) {
   const char* kNewCluster1Name = "new_cluster_1";
   const size_t kNumRpcs = 1000;