[OTel] Add latency view to example (#36601) (#36720)

Backport #36601 to v1.64.x

Needed to backport #36686

examples/cpp/otel/BUILD

@@ -14,11 +14,22 @@
 
 licenses(["notice"])
 
+cc_library(
+ name = "util",
+ srcs = ["util.cc"],
+ hdrs = ["util.h"],
+ deps = [
+ "//:grpc++",
+ "@io_opentelemetry_cpp//sdk/src/metrics",
+ ],
+)
+
 cc_binary(
  name = "greeter_callback_client",
  srcs = ["greeter_callback_client.cc"],
  defines = ["BAZEL_BUILD"],
  deps = [
+ "util",
  "//:grpc++",
  "//:grpcpp_otel_plugin",
  "//examples/protos:helloworld_cc_grpc",
@@ -34,6 +45,7 @@ cc_binary(
  srcs = ["greeter_callback_server.cc"],
  defines = ["BAZEL_BUILD"],
  deps = [
+ "util",
  "//:grpc++",
  "//:grpc++_reflection",
  "//:grpcpp_otel_plugin",

examples/cpp/otel/greeter_callback_client.cc

@@ -33,9 +33,11 @@
 #include <grpcpp/grpcpp.h>
 
 #ifdef BAZEL_BUILD
+#include "examples/cpp/otel/util.h"
 #include "examples/protos/helloworld.grpc.pb.h"
 #else
 #include "helloworld.grpc.pb.h"
+#include "util.h"
 #endif
 
 ABSL_FLAG(std::string, target, "localhost:50051", "Server address");
@@ -110,6 +112,10 @@ int main(int argc, char** argv) {
  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));
  auto status = grpc::OpenTelemetryPluginBuilder()
  .SetMeterProvider(std::move(meter_provider))

examples/cpp/otel/greeter_callback_server.cc

@@ -33,9 +33,11 @@
 #include <grpcpp/health_check_service_interface.h>
 
 #ifdef BAZEL_BUILD
+#include "examples/cpp/otel/util.h"
 #include "examples/protos/helloworld.grpc.pb.h"
 #else
 #include "helloworld.grpc.pb.h"
+#include "util.h"
 #endif
 
 ABSL_FLAG(uint16_t, port, 50051, "Server port for the service");
@@ -96,6 +98,10 @@ int main(int argc, char** argv) {
  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 status = grpc::OpenTelemetryPluginBuilder()
  .SetMeterProvider(std::move(meter_provider))

examples/cpp/otel/util.cc

@@ -0,0 +1,50 @@
+//
+//
+// Copyright 2024 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.
+//
+//
+
+#ifdef BAZEL_BUILD
+#include "examples/cpp/otel/util.h"
+#else
+#include "util.h"
+#endif
+
+#include "opentelemetry/sdk/metrics/view/instrument_selector_factory.h"
+#include "opentelemetry/sdk/metrics/view/meter_selector_factory.h"
+#include "opentelemetry/sdk/metrics/view/view_factory.h"
+
+#include <grpcpp/grpcpp.h>
+
+void AddLatencyView(opentelemetry::sdk::metrics::MeterProvider* provider,
+ const std::string& name, const std::string& unit) {
+ auto histogram_config = std::make_shared<
+ opentelemetry::sdk::metrics::HistogramAggregationConfig>();
+ histogram_config->boundaries_ = {
+ 0, 0.00001, 0.00005, 0.0001, 0.0003, 0.0006, 0.0008, 0.001, 0.002,
+ 0.003, 0.004, 0.005, 0.006, 0.008, 0.01, 0.013, 0.016, 0.02,
+ 0.025, 0.03, 0.04, 0.05, 0.065, 0.08, 0.1, 0.13, 0.16,
+ 0.2, 0.25, 0.3, 0.4, 0.5, 0.65, 0.8, 1, 2,
+ 5, 10, 20, 50, 100};
+ provider->AddView(
+ opentelemetry::sdk::metrics::InstrumentSelectorFactory::Create(
+ opentelemetry::sdk::metrics::InstrumentType::kHistogram, name, unit),
+ opentelemetry::sdk::metrics::MeterSelectorFactory::Create(
+ "grpc-c++", grpc::Version(), ""),
+ opentelemetry::sdk::metrics::ViewFactory::Create(
+ name, "", unit,
+ opentelemetry::sdk::metrics::AggregationType::kHistogram,
+ std::move(histogram_config)));
+}

examples/cpp/otel/util.h

@@ -0,0 +1,31 @@
+//
+//
+// Copyright 2024 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.
+//
+//
+
+#ifndef GRPCPP_EXAMPLES_CPP_OTEL_UTIL_H
+#define GRPCPP_EXAMPLES_CPP_OTEL_UTIL_H
+
+#include <string>
+
+#include "opentelemetry/sdk/metrics/meter_provider.h"
+
+// Helper function that adds view for gRPC latency instrument \a name with unit
+// \a unit with bucket boundaries that are more useful for RPCs.
+void AddLatencyView(opentelemetry::sdk::metrics::MeterProvider* provider,
+ const std::string& name, const std::string& unit);
+
+#endif // GRPCPP_EXAMPLES_CPP_OTEL_UTIL_H