[CSM] Remove experimental CSM PluginOption API in favor of CsmObservability API (#35812)

Also update interop tests to use `CsmObservability` API

Closes #35812

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/35812 from yashykt:UpdateCsmInterop dc99764aea
PiperOrigin-RevId: 604726881

include/grpcpp/ext/csm_observability.h

@@ -26,7 +26,7 @@
 #include "absl/functional/any_invocable.h"
 #include "absl/status/statusor.h"
 #include "absl/strings/string_view.h"
-#include "opentelemetry/sdk/metrics/meter_provider.h"
+#include "opentelemetry/metrics/meter_provider.h"
 
 #include <grpcpp/ext/otel_plugin.h>
 
@@ -40,7 +40,15 @@ namespace experimental {
 
 // This is a no-op at present, but in the future, this object would be useful
 // for performing cleanup.
-class CsmObservability {};
+class CsmObservability {
+ public:
+  CsmObservability() = default;
+  // Disable copy constructor and copy-assignment operator.
+  CsmObservability(const CsmObservability&) = delete;
+  CsmObservability& operator=(const CsmObservability&) = delete;
+  CsmObservability(CsmObservability&&) = default;
+  CsmObservability& operator=(CsmObservability&&) = default;
+};
 
 // CsmObservabilityBuilder configures observability for all service mesh traffic
 // for a binary running on CSM.
@@ -49,8 +57,7 @@ class CsmObservabilityBuilder {
   CsmObservabilityBuilder();
   ~CsmObservabilityBuilder();
   CsmObservabilityBuilder& SetMeterProvider(
-      std::shared_ptr<opentelemetry::sdk::metrics::MeterProvider>
-          meter_provider);
+      std::shared_ptr<opentelemetry::metrics::MeterProvider> meter_provider);
   // If set, \a target_attribute_filter is called per channel to decide whether
   // to record the target attribute on client or to replace it with "other".
   // This helps reduce the cardinality on metrics in cases where many channels
@@ -90,16 +97,6 @@ class CsmObservabilityBuilder {
   std::unique_ptr<grpc::internal::OpenTelemetryPluginBuilderImpl> builder_;
 };
 
-/// Creates an OpenTelemetryPluginOption that would add additional labels on
-/// gRPC metrics to enhance observability for CSM users.
-///
-/// Sample Usage -
-/// OpenTelemetryPluginBuilder()
-///     .SetMeterProvider(provider)
-///     .AddPluginOption(MakeCsmOpenTelemetryPluginOption())
-///     .BuildAndRegisterGlobal();
-std::unique_ptr<OpenTelemetryPluginOption> MakeCsmOpenTelemetryPluginOption();
-
 }  // namespace experimental
 }  // namespace grpc
 

src/cpp/ext/csm/BUILD

@@ -46,6 +46,7 @@ grpc_cc_library(
         "absl/types:optional",
         "absl/types:variant",
         "google_cloud_cpp:opentelemetry",
+        "otel/api",
         "otel/sdk/src/metrics",
         "otel/sdk:headers",
         "upb_base_lib",

src/cpp/ext/csm/csm_observability.cc

@@ -107,8 +107,7 @@ CsmObservabilityBuilder::CsmObservabilityBuilder()
 CsmObservabilityBuilder::~CsmObservabilityBuilder() = default;
 
 CsmObservabilityBuilder& CsmObservabilityBuilder::SetMeterProvider(
-    std::shared_ptr<opentelemetry::sdk::metrics::MeterProvider>
-        meter_provider) {
+    std::shared_ptr<opentelemetry::metrics::MeterProvider> meter_provider) {
   builder_->SetMeterProvider(meter_provider);
   return *this;
 }
@@ -139,9 +138,5 @@ absl::StatusOr<CsmObservability> CsmObservabilityBuilder::BuildAndRegister() {
   return CsmObservability();
 }
 
-std::unique_ptr<OpenTelemetryPluginOption> MakeCsmOpenTelemetryPluginOption() {
-  return std::make_unique<grpc::internal::CsmOpenTelemetryPluginOption>();
-}
-
 }  // namespace experimental
 }  // namespace grpc

test/cpp/ext/csm/csm_observability_test.cc

@@ -63,14 +63,6 @@ TEST(CsmChannelTargetSelectorTest, XdsTargetsWithTDAuthority) {
       "xds://traffic-director-global.xds.googleapis.com/foo"));
 }
 
-TEST(CsmPluginOptionTest, Basic) {
-  EXPECT_EQ(
-      OpenTelemetryPluginBuilder()
-          .AddPluginOption(experimental::MakeCsmOpenTelemetryPluginOption())
-          .BuildAndRegisterGlobal(),
-      absl::OkStatus());
-}
-
 }  // namespace
 }  // namespace testing
 }  // namespace grpc

test/cpp/interop/xds_interop_client.cc

@@ -427,7 +427,7 @@ void RunTestLoop(std::chrono::duration<double> duration_per_query,
   GPR_UNREACHABLE_CODE(thread.join());
 }
 
-void EnableCsmObservability() {
+grpc::experimental::CsmObservability EnableCsmObservability() {
   gpr_log(GPR_DEBUG, "Registering Prometheus exporter");
   opentelemetry::exporter::metrics::PrometheusExporterOptions opts;
   // default was "localhost:9464" which causes connection issue across GKE
@@ -438,12 +438,11 @@ void EnableCsmObservability() {
   auto meter_provider =
       std::make_shared<opentelemetry::sdk::metrics::MeterProvider>();
   meter_provider->AddMetricReader(std::move(prometheus_exporter));
-  assert(grpc::OpenTelemetryPluginBuilder()
-             .AddPluginOption(
-                 grpc::experimental::MakeCsmOpenTelemetryPluginOption())
-             .SetMeterProvider(std::move(meter_provider))
-             .BuildAndRegisterGlobal()
-             .ok());
+  auto observability = grpc::experimental::CsmObservabilityBuilder()
+                           .SetMeterProvider(std::move(meter_provider))
+                           .BuildAndRegister();
+  assert(observability.ok());
+  return *std::move(observability);
 }
 
 void RunServer(const int port, StatsWatchers* stats_watchers,
@@ -554,8 +553,9 @@ int main(int argc, char** argv) {
   }
 
   BuildRpcConfigsFromFlags(&rpc_config_queue);
+  grpc::experimental::CsmObservability observability;
   if (absl::GetFlag(FLAGS_enable_csm_observability)) {
-    EnableCsmObservability();
+    observability = EnableCsmObservability();
   }
 
   std::chrono::duration<double> duration_per_query =

test/cpp/interop/xds_interop_server.cc

@@ -43,7 +43,7 @@ ABSL_FLAG(bool, secure_mode, false,
 ABSL_FLAG(bool, enable_csm_observability, false,
           "Whether to enable CSM Observability");
 
-void EnableCsmObservability() {
+grpc::experimental::CsmObservability EnableCsmObservability() {
   gpr_log(GPR_DEBUG, "Registering Prometheus exporter");
   opentelemetry::exporter::metrics::PrometheusExporterOptions opts;
   // default was "localhost:9464" which causes connection issue across GKE
@@ -54,12 +54,11 @@ void EnableCsmObservability() {
   auto meter_provider =
       std::make_shared<opentelemetry::sdk::metrics::MeterProvider>();
   meter_provider->AddMetricReader(std::move(prometheus_exporter));
-  assert(grpc::OpenTelemetryPluginBuilder()
-             .AddPluginOption(
-                 grpc::experimental::MakeCsmOpenTelemetryPluginOption())
-             .SetMeterProvider(std::move(meter_provider))
-             .BuildAndRegisterGlobal()
-             .ok());
+  auto observability = grpc::experimental::CsmObservabilityBuilder()
+                           .SetMeterProvider(std::move(meter_provider))
+                           .BuildAndRegister();
+  assert(observability.ok());
+  return *std::move(observability);
 }
 
 int main(int argc, char** argv) {
@@ -82,8 +81,9 @@ int main(int argc, char** argv) {
   }
   grpc::EnableDefaultHealthCheckService(false);
   bool enable_csm_observability = absl::GetFlag(FLAGS_enable_csm_observability);
+  grpc::experimental::CsmObservability observability;
   if (enable_csm_observability) {
-    EnableCsmObservability();
+    observability = EnableCsmObservability();
   }
   grpc::testing::RunServer(absl::GetFlag(FLAGS_secure_mode),
                            enable_csm_observability, port, maintenance_port,