Cloud Trace API C++ Client Library

An idiomatic C++ client library for the Cloud Trace API, a service to send application trace data to Cloud Trace for viewing. This library is used to interact with the Trace API directly. If you are looking to instrument your application for Cloud Trace, we recommend using OpenTelemetry or a similar framework.

While this library is GA, please note Google Cloud C++ client libraries do not follow Semantic Versioning.


The following shows the code that you'll run in the google/cloud/trace/quickstart/ directory, which should give you a taste of the Cloud Trace API C++ client library API.

#include "google/cloud/trace/v2/trace_client.h"
#include "google/cloud/project.h"
#include <google/protobuf/util/time_util.h>
#include <iostream>
#include <random>
#include <thread>

std::string RandomHexDigits(std::mt19937_64& gen, int count) {
  auto const digits = std::string{"0123456789abcdef"};
  std::string sample;
  std::generate_n(std::back_inserter(sample), count, [&] {
    auto n = digits.size() - 1;
    return digits[std::uniform_int_distribution<std::size_t>(0, n)(gen)];
  return sample;

int main(int argc, char* argv[]) try {
  if (argc != 2) {
    std::cerr << "Usage: " << argv[0] << " project-id\n";
    return 1;

  namespace trace = ::google::cloud::trace_v2;
  namespace v2 = ::google::devtools::cloudtrace::v2;
  using ::google::protobuf::util::TimeUtil;

  auto client = trace::TraceServiceClient(trace::MakeTraceServiceConnection());

  // Create a span ID using some random hex digits.
  auto gen = std::mt19937_64(std::random_device{}());
  v2::Span span;
  auto span_id = RandomHexDigits(gen, 16);
  span.set_name(std::string{"projects/"} + argv[1] + "/traces/" +
                RandomHexDigits(gen, 32) + "/spans/" + span_id);
  *span.mutable_start_time() = (TimeUtil::GetCurrentTime)();
  // Simulate a call using a small sleep
  *span.mutable_end_time() = (TimeUtil::GetCurrentTime)();

  auto response = client.CreateSpan(span);
  if (!response) throw std::move(response).status();
  std::cout << response->DebugString() << "\n";

  return 0;
} catch (google::cloud::Status const& status) {
  std::cerr << "google::cloud::Status thrown: " << status << "\n";
  return 1;

Main classes

This library offers multiple *Client classes, which are listed below. Each one of these classes exposes all the RPCs for a service as member functions of the class. This library groups multiple services because they are part of the same product or are often used together. A typical example may be the administrative and data plane operations for a single product.

The library also has other classes that provide helpers, configuration parameters, and infrastructure to mock the *Client classes when testing your application.

More Information