C++ と OpenTelemetry

namespace gc = ::google::cloud;
[](std::string project_id) {
  auto project = gc::Project(std::move(project_id));
  auto configuration = gc::otel::ConfigureBasicTracing(project);

  MyApplicationCode();
}

namespace gc = ::google::cloud;
[](std::string project_id) {
  auto project = gc::Project(std::move(project_id));
  auto options = gc::Options{}.set<gc::otel::BasicTracingRateOption>(.001);
  auto configuration = gc::otel::ConfigureBasicTracing(project, options);

  MyApplicationCode();
}

namespace gc = ::google::cloud;
using ::opentelemetry::trace::Scope;
[](std::string project_id) {
  // Use the Cloud Trace Exporter directly.
  auto project = gc::Project(std::move(project_id));
  auto exporter = gc::otel::MakeTraceExporter(project);

  // Advanced use cases may need to create their own tracer provider, e.g. to
  // export to Cloud Trace and another backend simultaneously. In this
  // example, we just tweak some OpenTelemetry settings that google-cloud-cpp
  // does not expose.
  opentelemetry::sdk::trace::BatchSpanProcessorOptions options;
  options.schedule_delay_millis = std::chrono::milliseconds(1000);
  auto processor =
      opentelemetry::sdk::trace::BatchSpanProcessorFactory::Create(
          std::move(exporter), options);

  // Create a tracer provider and set it as the global trace provider
  opentelemetry::trace::Provider::SetTracerProvider(
      std::shared_ptr<opentelemetry::trace::TracerProvider>(
          opentelemetry::sdk::trace::TracerProviderFactory::Create(
              std::move(processor))));

  MyApplicationCode();

  // Clear the global trace provider
  opentelemetry::trace::Provider::SetTracerProvider(
      opentelemetry::nostd::shared_ptr<
          opentelemetry::trace::TracerProvider>());
}

// For more details on the OpenTelemetry code in this sample, see:
//     https://opentelemetry.io/docs/instrumentation/cpp/manual/
namespace gc = ::google::cloud;
using ::opentelemetry::trace::Scope;
[](std::string project_id) {
  auto project = gc::Project(std::move(project_id));
  auto configuration = gc::otel::ConfigureBasicTracing(project);

  // Initialize the `Tracer`. This would typically be done once.
  auto provider = opentelemetry::trace::Provider::GetTracerProvider();
  auto tracer = provider->GetTracer("my-application");

  // If your application makes multiple client calls that are logically
  // connected, you may want to instrument your application.
  auto my_function = [tracer] {
    // Start an active span. The span is ended when the `Scope` object is
    // destroyed.
    auto scope = Scope(tracer->StartSpan("my-function-span"));

    // Any spans created by the client library will be children of
    // "my-function-span". i.e. In the distributed trace, the client calls are
    // sub-units of work of `my_function()`, and will be displayed as such in
    // Cloud Trace.
    Client client;
    client.CreateFoo();
    client.DeleteFoo();
  };

  // As an example, start a span to cover both calls to `my_function()`.
  auto scope = Scope(tracer->StartSpan("my-application-span"));
  my_function();
  my_function();
}