[CSM O11y] Add example without Stateful Session Affinity (#36806)

Fork the existing CSM example and just keep the observability parts.

Closes #36806

PiperOrigin-RevId: 640580476

examples/cpp/csm/observability/BUILD

@@ -0,0 +1,50 @@
+# Copyright 2023 the gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+licenses(["notice"])
+
+cc_binary(
+    name = "csm_greeter_client",
+    srcs = ["csm_greeter_client.cc"],
+    defines = ["BAZEL_BUILD"],
+    deps = [
+        "//:grpc++",
+        "//:grpcpp_csm_observability",
+        "//examples/cpp/otel:util",
+        "//examples/protos:helloworld_cc_grpc",
+        "@com_google_absl//absl/flags:flag",
+        "@com_google_absl//absl/flags:parse",
+        "@io_opentelemetry_cpp//exporters/prometheus:prometheus_exporter",
+        "@io_opentelemetry_cpp//sdk/src/metrics",
+    ],
+)
+
+cc_binary(
+    name = "csm_greeter_server",
+    srcs = ["csm_greeter_server.cc"],
+    defines = ["BAZEL_BUILD"],
+    deps = [
+        "//:grpc++",
+        "//:grpc++_reflection",
+        "//:grpcpp_admin",
+        "//:grpcpp_csm_observability",
+        "//examples/cpp/otel:util",
+        "//examples/protos:helloworld_cc_grpc",
+        "@com_google_absl//absl/flags:flag",
+        "@com_google_absl//absl/flags:parse",
+        "@com_google_absl//absl/log",
+        "@io_opentelemetry_cpp//exporters/prometheus:prometheus_exporter",
+        "@io_opentelemetry_cpp//sdk/src/metrics",
+    ],
+)

examples/cpp/csm/observability/Dockerfile.client

@@ -0,0 +1,39 @@
+# Copyright 2023 The gRPC Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM python:3.9-slim-bookworm
+
+RUN apt-get update -y && apt-get upgrade -y && apt-get install -y build-essential clang curl
+
+WORKDIR /workdir
+
+RUN ln -s /usr/bin/python3 /usr/bin/python
+RUN mkdir /artifacts
+
+COPY . .
+RUN tools/bazel build //examples/cpp/csm/observability:csm_greeter_client
+RUN cp -rL /workdir/bazel-bin/examples/cpp/csm/observability/csm_greeter_client /artifacts/
+
+FROM python:3.9-slim-bookworm
+
+RUN apt-get update \
+    && apt-get -y upgrade \
+    && apt-get -y autoremove \
+    && apt-get install -y curl
+
+COPY --from=0 /artifacts ./
+
+ENV GRPC_EXPERIMENTAL_XDS_ENABLE_OVERRIDE_HOST=true
+
+ENTRYPOINT ["/csm_greeter_client"]

examples/cpp/csm/observability/Dockerfile.server

@@ -0,0 +1,39 @@
+# Copyright 2023 The gRPC Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM python:3.9-slim-bookworm
+
+RUN apt-get update -y && apt-get upgrade -y && apt-get install -y build-essential clang curl
+
+WORKDIR /workdir
+
+RUN ln -s /usr/bin/python3 /usr/bin/python
+RUN mkdir /artifacts
+
+COPY . .
+RUN OVERRIDE_BAZEL_VERSION=5.4.0 tools/bazel build //examples/cpp/csm/observability:csm_greeter_server
+RUN cp -rL /workdir/bazel-bin/examples/cpp/csm/observability/csm_greeter_server /artifacts/
+
+FROM python:3.9-slim-bookworm
+
+RUN apt-get update \
+    && apt-get -y upgrade \
+    && apt-get -y autoremove \
+    && apt-get install -y curl
+
+COPY --from=0 /artifacts ./
+
+ENV GRPC_EXPERIMENTAL_XDS_ENABLE_OVERRIDE_HOST=true
+
+ENTRYPOINT ["/csm_greeter_server"]

examples/cpp/csm/observability/README.md

@@ -0,0 +1,35 @@
+# gRPC C++ CSM Hello World Example
+
+This CSM example builds on the [Hello World Example](https://github.com/grpc/grpc/tree/master/examples/cpp/helloworld) and changes the gRPC client and server to accept configuration from an xDS control plane and test CSM observability.
+
+## Configuration
+
+The client takes the following command-line arguments -
+* target - By default, the client tries to connect to the xDS "xds:///helloworld:50051" and gRPC would use xDS to resolve this target and connect to the server backend. This can be overridden to change the target.
+* prometheus_endpoint - Endpoint used for prometheus. Default value is localhost:9464
+
+
+The server takes the following command-line arguments -
+* port - Port on which the Hello World service is run. Defaults to 50051.
+* prometheus_endpoint - Endpoint used for prometheus. Default value is localhost:9464
+
+## Building
+
+From the gRPC workspace folder:
+
+Client:
+```
+docker build -f examples/cpp/csm/observability/Dockerfile.client
+```
+Server:
+```
+docker build -f examples/cpp/csm/observability/Dockerfile.server
+```
+
+To push to a registry, add a tag to the image either by adding a `-t` flag to `docker build` command above or run:
+
+```
+docker image tag ${sha from build command above} ${tag}
+```
+
+And then push the tagged image using `docker push`

examples/cpp/csm/observability/csm_greeter_client.cc

@@ -0,0 +1,79 @@
+/*
+ *
+ * Copyright 2023 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <sys/types.h>
+
+#include <chrono>
+#include <condition_variable>
+#include <iostream>
+#include <memory>
+#include <string>
+
+#include "absl/flags/flag.h"
+#include "absl/flags/parse.h"
+#include "absl/types/optional.h"
+#include "examples/cpp/otel/util.h"
+#include "opentelemetry/exporters/prometheus/exporter_factory.h"
+#include "opentelemetry/exporters/prometheus/exporter_options.h"
+#include "opentelemetry/sdk/metrics/meter_provider.h"
+
+#include <grpcpp/ext/csm_observability.h>
+#include <grpcpp/grpcpp.h>
+#include <grpcpp/support/string_ref.h>
+
+ABSL_FLAG(std::string, target, "xds:///helloworld:50051", "Target string");
+ABSL_FLAG(std::string, prometheus_endpoint, "localhost:9464",
+          "Prometheus exporter endpoint");
+
+namespace {
+
+absl::StatusOr<grpc::CsmObservability> InitializeObservability() {
+  opentelemetry::exporter::metrics::PrometheusExporterOptions opts;
+  // default was "localhost:9464" which causes connection issue across GKE pods
+  opts.url = "0.0.0.0:9464";
+  auto prometheus_exporter =
+      opentelemetry::exporter::metrics::PrometheusExporterFactory::Create(opts);
+  auto meter_provider =
+      std::make_shared<opentelemetry::sdk::metrics::MeterProvider>();
+  // The default histogram boundaries are not granular enough for RPCs. Override
+  // the "grpc.client.attempt.duration" view as recommended by
+  // https://github.com/grpc/proposal/blob/master/A66-otel-stats.md.
+  AddLatencyView(meter_provider.get(), "grpc.client.attempt.duration", "s");
+  meter_provider->AddMetricReader(std::move(prometheus_exporter));
+  return grpc::CsmObservabilityBuilder()
+      .SetMeterProvider(std::move(meter_provider))
+      .BuildAndRegister();
+}
+
+}  // namespace
+
+int main(int argc, char** argv) {
+  absl::ParseCommandLine(argc, argv);
+  // Setup CSM observability
+  auto observability = InitializeObservability();
+  if (!observability.ok()) {
+    std::cerr << "CsmObservability::Init() failed: "
+              << observability.status().ToString() << std::endl;
+    return static_cast<int>(observability.status().code());
+  }
+
+  // Continuously send RPCs every second.
+  RunClient(absl::GetFlag(FLAGS_target));
+
+  return 0;
+}

examples/cpp/csm/observability/csm_greeter_server.cc

@@ -0,0 +1,67 @@
+/*
+ *
+ * Copyright 2023 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <iostream>
+#include <memory>
+#include <string>
+
+#include "absl/flags/flag.h"
+#include "absl/flags/parse.h"
+#include "absl/log/log.h"
+#include "absl/strings/str_cat.h"
+#include "examples/cpp/otel/util.h"
+#include "opentelemetry/exporters/prometheus/exporter_factory.h"
+#include "opentelemetry/exporters/prometheus/exporter_options.h"
+#include "opentelemetry/sdk/metrics/meter_provider.h"
+
+#include <grpcpp/ext/admin_services.h>
+#include <grpcpp/ext/csm_observability.h>
+#include <grpcpp/ext/proto_server_reflection_plugin.h>
+#include <grpcpp/grpcpp.h>
+#include <grpcpp/health_check_service_interface.h>
+#include <grpcpp/xds_server_builder.h>
+
+ABSL_FLAG(int32_t, port, 50051, "Server port for service.");
+ABSL_FLAG(std::string, prometheus_endpoint, "localhost:9464",
+          "Prometheus exporter endpoint");
+
+int main(int argc, char** argv) {
+  absl::ParseCommandLine(argc, argv);
+  opentelemetry::exporter::metrics::PrometheusExporterOptions opts;
+  // default was "localhost:9464" which causes connection issue across GKE pods
+  opts.url = "0.0.0.0:9464";
+  auto prometheus_exporter =
+      opentelemetry::exporter::metrics::PrometheusExporterFactory::Create(opts);
+  auto meter_provider =
+      std::make_shared<opentelemetry::sdk::metrics::MeterProvider>();
+  // The default histogram boundaries are not granular enough for RPCs. Override
+  // the "grpc.server.call.duration" view as recommended by
+  // https://github.com/grpc/proposal/blob/master/A66-otel-stats.md.
+  AddLatencyView(meter_provider.get(), "grpc.server.call.duration", "s");
+  meter_provider->AddMetricReader(std::move(prometheus_exporter));
+  auto observability = grpc::CsmObservabilityBuilder()
+                           .SetMeterProvider(std::move(meter_provider))
+                           .BuildAndRegister();
+  if (!observability.ok()) {
+    std::cerr << "CsmObservability::Init() failed: "
+              << observability.status().ToString() << std::endl;
+    return static_cast<int>(observability.status().code());
+  }
+  RunServer(absl::GetFlag(FLAGS_port));
+  return 0;
+}

examples/cpp/otel/BUILD

@@ -15,7 +15,7 @@
 licenses(["notice"])
 
 package(
-    default_visibility = ["//examples/cpp/otel:__subpackages__"],
+    default_visibility = ["//examples/cpp:__subpackages__"],
 )
 
 cc_library(