[OTel] Add back server_selector that got deleted by a merge fiasco (#35532)

It looks like this ended up getting deleted in https://github.com/grpc/grpc/pull/34350 probably when merging.

Also, the `Init` method in the otel test library is getting unwieldy. I'm going to send out a follow-up PR to convert this into a builder instead.

Closes #35532

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/35532 from yashykt:OTelPluginBuilderFix 372bf26338cb89b440fbb470a1fe3388d0002070
PiperOrigin-RevId: 597846622

6 files changed, 86 insertions, 2 deletions

diff --git a/src/core/lib/channel/call_tracer.cc b/src/core/lib/channel/call_tracer.cc
index d98a944b59..83a8ec8b22 100644
--- a/src/core/lib/channel/call_tracer.cc
+++ b/src/core/lib/channel/call_tracer.cc
@@ -60,6 +60,11 @@ void ServerCallTracerFactory::RegisterGlobal(ServerCallTracerFactory* factory) {
   g_server_call_tracer_factory_ = factory;
 }
 
+void ServerCallTracerFactory::TestOnlyReset() {
+  delete g_server_call_tracer_factory_;
+  g_server_call_tracer_factory_ = nullptr;
+}
+
 absl::string_view ServerCallTracerFactory::ChannelArgName() {
   return kServerCallTracerFactoryChannelArgName;
 }
diff --git a/src/core/lib/channel/call_tracer.h b/src/core/lib/channel/call_tracer.h
index 34c8342dc3..6116a26a20 100644
--- a/src/core/lib/channel/call_tracer.h
+++ b/src/core/lib/channel/call_tracer.h
@@ -201,6 +201,9 @@ class ServerCallTracerFactory {
   // this for the lifetime of the process.
   static void RegisterGlobal(ServerCallTracerFactory* factory);
 
+  // Deletes any previous registered ServerCallTracerFactory.
+  static void TestOnlyReset();
+
   static absl::string_view ChannelArgName();
 };
 
diff --git a/src/cpp/ext/otel/otel_plugin.cc b/src/cpp/ext/otel/otel_plugin.cc
index 7f7ba290e4..8f3593e94f 100644
--- a/src/cpp/ext/otel/otel_plugin.cc
+++ b/src/cpp/ext/otel/otel_plugin.cc
@@ -246,6 +246,7 @@ void OpenTelemetryPluginBuilderImpl::BuildAndRegisterGlobal() {
   g_otel_plugin_state_->labels_injector = std::move(labels_injector_);
   g_otel_plugin_state_->target_attribute_filter =
       std::move(target_attribute_filter_);
+  g_otel_plugin_state_->server_selector = std::move(server_selector_);
   g_otel_plugin_state_->generic_method_attribute_filter =
       std::move(generic_method_attribute_filter_);
   g_otel_plugin_state_->meter_provider = std::move(meter_provider);
diff --git a/test/cpp/ext/otel/otel_plugin_test.cc b/test/cpp/ext/otel/otel_plugin_test.cc
index 541e49d417..e5eff6e7da 100644
--- a/test/cpp/ext/otel/otel_plugin_test.cc
+++ b/test/cpp/ext/otel/otel_plugin_test.cc
@@ -358,6 +358,54 @@ TEST_F(OpenTelemetryPluginEnd2EndTest, TargetSelectorReturnsFalse) {
   ASSERT_TRUE(data.empty());
 }
 
+// Test that a server selector returning true records metrics on the server.
+TEST_F(OpenTelemetryPluginEnd2EndTest, ServerSelectorReturnsTrue) {
+  Init({grpc::OpenTelemetryPluginBuilder::
+            kServerCallDurationInstrumentName}, /*resource=*/
+       opentelemetry::sdk::resource::Resource::Create({}),
+       /*labels_injector=*/nullptr,
+       /*test_no_meter_provider=*/false,
+       /*labels_to_inject=*/{},
+       /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       [](const grpc_core::ChannelArgs& /*channel_args*/) { return true; });
+  SendRPC();
+  const char* kMetricName = "grpc.server.call.duration";
+  auto data = ReadCurrentMetricsData(
+      [&](const absl::flat_hash_map<
+          std::string,
+          std::vector<opentelemetry::sdk::metrics::PointDataAttributes>>&
+              data) { return !data.contains(kMetricName); });
+  ASSERT_EQ(data[kMetricName].size(), 1);
+  const auto& server_attributes =
+      data[kMetricName][0].attributes.GetAttributes();
+  EXPECT_EQ(server_attributes.size(), 2);
+  EXPECT_EQ(absl::get<std::string>(server_attributes.at("grpc.method")),
+            kMethodName);
+  EXPECT_EQ(absl::get<std::string>(server_attributes.at("grpc.status")), "OK");
+}
+
+// Test that a server selector returning false does not record metrics on the
+// server.
+TEST_F(OpenTelemetryPluginEnd2EndTest, ServerSelectorReturnsFalse) {
+  Init({grpc::OpenTelemetryPluginBuilder::
+            kServerCallDurationInstrumentName}, /*resource=*/
+       opentelemetry::sdk::resource::Resource::Create({}),
+       /*labels_injector=*/nullptr,
+       /*test_no_meter_provider=*/false,
+       /*labels_to_inject=*/{},
+       /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       [](const grpc_core::ChannelArgs& /*channel_args*/) { return false; });
+  SendRPC();
+  auto data = ReadCurrentMetricsData(
+      [&](const absl::flat_hash_map<
+          std::string,
+          std::vector<opentelemetry::sdk::metrics::PointDataAttributes>>&
+          /*data*/) { return false; });
+  ASSERT_TRUE(data.empty());
+}
+
 // Test that a target attribute filter returning true records metrics with the
 // target as is on the channel.
 TEST_F(OpenTelemetryPluginEnd2EndTest, TargetAttributeFilterReturnsTrue) {
@@ -368,6 +416,8 @@ TEST_F(OpenTelemetryPluginEnd2EndTest, TargetAttributeFilterReturnsTrue) {
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/[](absl::string_view /*target*/) {
          return true;
        });
@@ -407,6 +457,8 @@ TEST_F(OpenTelemetryPluginEnd2EndTest, TargetAttributeFilterReturnsFalse) {
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        [server_address = canonical_server_address_](
            absl::string_view /*target*/) { return false; });
@@ -475,6 +527,8 @@ TEST_F(OpenTelemetryPluginEnd2EndTest,
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        absl::AnyInvocable<bool(absl::string_view) const>(),
        /*generic_method_attribute_filter=*/
@@ -515,6 +569,8 @@ TEST_F(OpenTelemetryPluginEnd2EndTest,
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        absl::AnyInvocable<bool(absl::string_view) const>(),
        /*generic_method_attribute_filter=*/
@@ -583,6 +639,8 @@ TEST_F(OpenTelemetryPluginEnd2EndTest,
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        absl::AnyInvocable<bool(absl::string_view) const>(),
        /*generic_method_attribute_filter=*/
@@ -622,6 +680,8 @@ TEST_F(OpenTelemetryPluginEnd2EndTest,
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        absl::AnyInvocable<bool(absl::string_view) const>(),
        /*generic_method_attribute_filter=*/
@@ -757,6 +817,8 @@ TEST_F(OpenTelemetryPluginOptionEnd2EndTest, Basic) {
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        absl::AnyInvocable<bool(absl::string_view) const>(),
        /*generic_method_attribute_filter=*/
@@ -799,6 +861,8 @@ TEST_F(OpenTelemetryPluginOptionEnd2EndTest, ClientOnlyPluginOption) {
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        absl::AnyInvocable<bool(absl::string_view) const>(),
        /*generic_method_attribute_filter=*/
@@ -842,6 +906,8 @@ TEST_F(OpenTelemetryPluginOptionEnd2EndTest, ServerOnlyPluginOption) {
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        absl::AnyInvocable<bool(absl::string_view) const>(),
        /*generic_method_attribute_filter=*/
@@ -899,6 +965,8 @@ TEST_F(OpenTelemetryPluginOptionEnd2EndTest,
        /*test_no_meter_provider=*/false,
        /*labels_to_inject=*/{},
        /*target_selector=*/absl::AnyInvocable<bool(absl::string_view) const>(),
+       /*server_selector=*/
+       absl::AnyInvocable<bool(const grpc_core::ChannelArgs&) const>(),
        /*target_attribute_filter=*/
        absl::AnyInvocable<bool(absl::string_view) const>(),
        /*generic_method_attribute_filter=*/
diff --git a/test/cpp/ext/otel/otel_test_library.cc b/test/cpp/ext/otel/otel_test_library.cc
index 6f8e55a96d..19777d4d59 100644
--- a/test/cpp/ext/otel/otel_test_library.cc
+++ b/test/cpp/ext/otel/otel_test_library.cc
@@ -90,6 +90,9 @@ void OpenTelemetryPluginEnd2EndTest::Init(
     const std::map<std::string, std::string>& labels_to_inject,
     absl::AnyInvocable<bool(absl::string_view /*target*/) const>
         target_selector,
+    absl::AnyInvocable<bool(const grpc_core::ChannelArgs& /*channel_args*/)
+                           const>
+        server_selector,
     absl::AnyInvocable<bool(absl::string_view /*target*/) const>
         target_attribute_filter,
     absl::AnyInvocable<bool(absl::string_view /*generic_method*/) const>
@@ -121,6 +124,7 @@ void OpenTelemetryPluginEnd2EndTest::Init(
   }
   ot_builder.SetLabelsInjector(std::move(labels_injector));
   ot_builder.SetTargetSelector(std::move(target_selector));
+  ot_builder.SetServerSelector(std::move(server_selector));
   ot_builder.SetTargetAttributeFilter(std::move(target_attribute_filter));
   ot_builder.SetGenericMethodAttributeFilter(
       std::move(generic_method_attribute_filter));
@@ -160,8 +164,7 @@ void OpenTelemetryPluginEnd2EndTest::Init(
 void OpenTelemetryPluginEnd2EndTest::TearDown() {
   server_->Shutdown();
   grpc_shutdown_blocking();
-  delete grpc_core::ServerCallTracerFactory::Get(grpc_core::ChannelArgs());
-  grpc_core::ServerCallTracerFactory::RegisterGlobal(nullptr);
+  grpc_core::ServerCallTracerFactory::TestOnlyReset();
 }
 
 void OpenTelemetryPluginEnd2EndTest::ResetStub(
diff --git a/test/cpp/ext/otel/otel_test_library.h b/test/cpp/ext/otel/otel_test_library.h
index 0f6edfd157..0108145a57 100644
--- a/test/cpp/ext/otel/otel_test_library.h
+++ b/test/cpp/ext/otel/otel_test_library.h
@@ -66,6 +66,10 @@ class OpenTelemetryPluginEnd2EndTest : public ::testing::Test {
       const std::map<std::string, std::string>& labels_to_inject = {},
       absl::AnyInvocable<bool(absl::string_view /*target*/) const>
           target_selector = absl::AnyInvocable<bool(absl::string_view) const>(),
+      absl::AnyInvocable<bool(const grpc_core::ChannelArgs& /*channel_args*/)
+                             const>
+          server_selector = absl::AnyInvocable<
+              bool(const grpc_core::ChannelArgs& /*channel_args*/) const>(),
       absl::AnyInvocable<bool(absl::string_view /*target*/) const>
           target_attribute_filter =
               absl::AnyInvocable<bool(absl::string_view) const>(),