[CurrencyService] Add C++ Metrics (open-telemetry#759)

* Add cpp metrics

* Add IntCounter to CurrencyService

* changelog

* changelog

* Fix indentantion

* Add line break

* Remove unnecessary comma

* Remove unnecessary includes

* Apply suggestions

CHANGELOG.md

@@ -18,6 +18,8 @@ tls_certificate_check and bump to OTP-25
 ([#756](https://github.com/open-telemetry/opentelemetry-demo/pull/756))
 * Bump up OTEL Java Agent version to 1.23.0
 ([#757](https://github.com/open-telemetry/opentelemetry-demo/pull/757))
+* Add counter metric to currency service (C++)
+([#759](https://github.com/open-telemetry/opentelemetry-demo/issues/759))
 * Use browserDetector to populate browser info to frontend-web telemetry
 ([#760](https://github.com/open-telemetry/opentelemetry-demo/pull/760))
 

src/currencyservice/.dockerignore

@@ -1,2 +1,4 @@
 client.js
 node_modules/
+build/
+out/

src/currencyservice/CMakeLists.txt

@@ -1,8 +1,9 @@
 cmake_minimum_required(VERSION 3.1)
 project(currency-service)
 
-find_package(Protobuf)
-find_package(gRPC)
+find_package(Protobuf REQUIRED)
+find_package(gRPC CONFIG REQUIRED)
+find_package(opentelemetry-cpp CONFIG REQUIRED)
 
 set(PROTO_PATH "${CMAKE_CURRENT_SOURCE_DIR}/proto")
 set(GENERATED_PROTOBUF_PATH "${CMAKE_BINARY_DIR}/generated/proto")
@@ -56,12 +57,15 @@ add_library(demo-proto ${DEMO_PB_H_FILE}
            ${HEALTH_GRPC_PB_H_FILE})
 
 target_link_libraries(demo-proto gRPC::grpc++ protobuf::libprotobuf)
-include_directories("${GENERATED_PROTOBUF_PATH}")
+include_directories("${GENERATED_PROTOBUF_PATH}" "${OPENTELEMETRY_CPP_INCLUDE_DIRS}")
 
 add_executable(currencyservice src/server.cpp)
 add_dependencies(currencyservice demo-proto)
 target_link_libraries(
     currencyservice demo-proto protobuf::libprotobuf
-     opentelemetry_trace opentelemetry_common opentelemetry_exporter_otlp_grpc opentelemetry_exporter_otlp_grpc_client opentelemetry_proto opentelemetry_otlp_recordable opentelemetry_resources gRPC::grpc++)
+     ${OPENTELEMETRY_CPP_LIBRARIES} opentelemetry_trace opentelemetry_common 
+     opentelemetry_exporter_otlp_grpc opentelemetry_exporter_otlp_grpc_client 
+     opentelemetry_proto opentelemetry_otlp_recordable opentelemetry_resources 
+     opentelemetry_metrics opentelemetry_exporter_otlp_grpc_metrics gRPC::grpc++)
 
 install(TARGETS currencyservice DESTINATION bin)

src/currencyservice/Dockerfile

@@ -17,14 +17,14 @@ FROM alpine as builder
 RUN apk update
 RUN apk add git cmake make g++ grpc-dev re2-dev protobuf-dev c-ares-dev
 
-ARG OPENTELEMETRY_CPP_VERSION=1.8.1
+ARG OPENTELEMETRY_CPP_VERSION=1.8.2
 
 RUN git clone https://github.com/open-telemetry/opentelemetry-cpp \
 	&& cd opentelemetry-cpp/ \
     	&& git checkout tags/v${OPENTELEMETRY_CPP_VERSION} -b v${OPENTELEMETRY_CPP_VERSION} \
 	&& mkdir build \
 	&& cd build \
-	&& cmake .. -DCMAKE_POSITION_INDEPENDENT_CODE=ON -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTING=OFF -DWITH_EXAMPLES=OFF -DWITH_OTLP=ON \
+	&& cmake .. -DCMAKE_POSITION_INDEPENDENT_CODE=ON -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTING=OFF -DWITH_EXAMPLES=OFF -DWITH_OTLP=ON -DWITH_OTLP_GRPC=ON \
 	&& make -j$(nproc || sysctl -n hw.ncpu || echo 1) install && cd ../.. && rm -rf opentelemetry-cpp
 
 COPY . /currencyservice

src/currencyservice/src/meter_common.h

@@ -0,0 +1,64 @@
+// Copyright The OpenTelemetry 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 "opentelemetry/exporters/otlp/otlp_grpc_metric_exporter_factory.h"
+#include "opentelemetry/metrics/provider.h"
+#include "opentelemetry/sdk/metrics/export/periodic_exporting_metric_reader.h"
+#include "opentelemetry/sdk/metrics/meter.h"
+#include "opentelemetry/sdk/metrics/meter_provider.h"
+
+// namespaces
+namespace common        = opentelemetry::common;
+namespace metrics_api   = opentelemetry::metrics;
+namespace metric_sdk    = opentelemetry::sdk::metrics;
+namespace nostd         = opentelemetry::nostd;
+namespace otlp_exporter = opentelemetry::exporter::otlp;
+
+namespace
+{
+  std::string version{ "1.3.0" };
+  std::string name{ "app_currency" };
+  std::string schema{ "https://opentelemetry.io/schemas/1.2.0" };
+
+  void initMeter() 
+  {
+    // Build MetricExporter
+    otlp_exporter::OtlpGrpcMetricExporterOptions otlpOptions;
+
+    // Configuration via environment variable not supported yet
+    otlpOptions.endpoint = "otelcol:4317";
+    otlpOptions.aggregation_temporality = metric_sdk::AggregationTemporality::kDelta;
+    auto exporter = otlp_exporter::OtlpGrpcMetricExporterFactory::Create(otlpOptions);
+
+    // Build MeterProvider and Reader
+    metric_sdk::PeriodicExportingMetricReaderOptions options;
+    options.export_interval_millis = std::chrono::milliseconds(1000);
+    options.export_timeout_millis = std::chrono::milliseconds(500);
+    std::unique_ptr<metric_sdk::MetricReader> reader{
+        new metric_sdk::PeriodicExportingMetricReader(std::move(exporter), options) };
+    auto provider = std::shared_ptr<metrics_api::MeterProvider>(new metric_sdk::MeterProvider());
+    auto p = std::static_pointer_cast<metric_sdk::MeterProvider>(provider);
+    p->AddMetricReader(std::move(reader));
+    metrics_api::Provider::SetMeterProvider(provider);
+  }
+
+  nostd::unique_ptr<metrics_api::Counter<uint64_t>> initIntCounter()
+  {
+    std::string counter_name = name + "_counter";
+    auto provider = metrics_api::Provider::GetMeterProvider();
+    nostd::shared_ptr<metrics_api::Meter> meter = provider->GetMeter(name, version);
+    auto int_counter = meter->CreateUInt64Counter(counter_name);
+    return int_counter;
+  }
+}

src/currencyservice/src/server.cpp

@@ -22,6 +22,7 @@
 #include "opentelemetry/trace/span_context_kv_iterable_view.h"
 #include "opentelemetry/baggage/baggage.h"
 #include "opentelemetry/nostd/string_view.h"
+#include "meter_common.h"
 #include "tracer_common.h"
 
 #include <grpcpp/grpcpp.h>
@@ -48,9 +49,13 @@ using namespace opentelemetry::trace;
 using namespace opentelemetry::baggage;
 namespace context = opentelemetry::context;
 
+namespace metrics_api = opentelemetry::metrics;
+namespace nostd       = opentelemetry::nostd;
+
 namespace
 {
-  std::unordered_map<std::string, double> currency_conversion{
+  std::unordered_map<std::string, double> currency_conversion
+  {
     {"EUR", 1.0},
     {"USD", 1.1305},
     {"JPY", 126.40},
@@ -84,7 +89,9 @@ namespace
     {"SGD", 1.5349},
     {"THB", 36.012},
     {"ZAR", 16.0583},
-};
+  };
+
+  nostd::unique_ptr<metrics_api::Counter<uint64_t>> currency_counter;
 
 class HealthServer final : public grpc::health::v1::Health::Service
 {
@@ -202,6 +209,8 @@ class CurrencyService final : public oteldemo::CurrencyService::Service
       span->SetAttribute("app.currency.conversion.from", from_code);
       span->SetAttribute("app.currency.conversion.to", to_code);
 
+      CurrencyCounter(to_code);
+
       // End the span
       span->AddEvent("Conversion successful, response sent back");
       span->SetStatus(StatusCode::kOk);
@@ -218,6 +227,13 @@ class CurrencyService final : public oteldemo::CurrencyService::Service
     }
     return Status::OK;
   }
+
+  void CurrencyCounter(const std::string& currency_code)
+  {
+      std::map<std::string, std::string> labels = { {"currency_code", currency_code} };
+      auto labelkv = common::KeyValueIterableView<decltype(labels)>{ labels };
+      currency_counter->Add(1, labelkv);
+  }
 };
 
 void RunServer(uint16_t port)
@@ -250,7 +266,9 @@ int main(int argc, char **argv) {
   std::cout << "Port: " << port << "\n";
 
   initTracer();
+  initMeter();
+  currency_counter = initIntCounter();
   RunServer(port);
 
   return 0;
-}
+}