追蹤 C++ 應用程式

瞭解如何使用 OpenTelemetry 編譯及執行 C++ 範例，並將追蹤記錄匯出至 Cloud Trace。這個範例會使用 Google Cloud Pub/Sub C++ 用戶端發布 5 則訊息，並將追蹤記錄匯出至 Cloud Trace。

事前準備

登入 Google Cloud 帳戶。如果您是 Google Cloud新手，歡迎建立帳戶，親自評估產品在實際工作環境中的成效。新客戶還能獲得價值 $300 美元的免費抵免額，可用於執行、測試及部署工作負載。

In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

Roles required to select or create a project

Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
Create a project: To create a project, you need the Project Creator role (roles/resourcemanager.projectCreator), which contains the resourcemanager.projects.create permission. Learn how to grant roles.

Go to project selector

Verify that billing is enabled for your Google Cloud project.

Enable the Pub/Sub and Trace APIs.

Roles required to enable APIs

To enable APIs, you need the Service Usage Admin IAM role (roles/serviceusage.serviceUsageAdmin), which contains the serviceusage.services.enable permission. Learn how to grant roles.

Enable the APIs

安裝 Google Cloud CLI。

若您採用的是外部識別資訊提供者 (IdP)，請先使用聯合身分登入 gcloud CLI。

執行下列指令，初始化 gcloud CLI：

gcloud init

In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

Roles required to select or create a project

Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
Create a project: To create a project, you need the Project Creator role (roles/resourcemanager.projectCreator), which contains the resourcemanager.projects.create permission. Learn how to grant roles.

Go to project selector

Verify that billing is enabled for your Google Cloud project.

Enable the Pub/Sub and Trace APIs.

Roles required to enable APIs

To enable APIs, you need the Service Usage Admin IAM role (roles/serviceusage.serviceUsageAdmin), which contains the serviceusage.services.enable permission. Learn how to grant roles.

Enable the APIs

安裝 Google Cloud CLI。

若您採用的是外部識別資訊提供者 (IdP)，請先使用聯合身分登入 gcloud CLI。

執行下列指令，初始化 gcloud CLI：

gcloud init

設定

使用 ID my-topic 建立主題：
```
gcloud pubsub topics create my-topic
```

查看 C++ 範例原始碼：

git clone --depth 1 https://github.com/GoogleCloudPlatforms/cpp-samples

發布訊息

// Create a few namespace aliases to make the code easier to read.
namespace gc = ::google::cloud;
namespace otel = gc::otel;
namespace pubsub = gc::pubsub;

// This example uses a simple wrapper to export (upload) OTel tracing data
// to Google Cloud Trace. More complex applications may use different
// authentication, or configure their own OTel exporter.
auto project = gc::Project(project_id);
auto configuration = otel::ConfigureBasicTracing(project);

auto publisher = pubsub::Publisher(pubsub::MakePublisherConnection(
    pubsub::Topic(project_id, topic_id),
    // Configure this publisher to enable OTel tracing. Some applications may
    // chose to disable tracing in some publishers or to dynamically enable
    // this option based on their own configuration.
    gc::Options{}.set<gc::OpenTelemetryTracingOption>(true)));

// After this point, use the Cloud Pub/Sub C++ client library as usual.
// In this example, we will send a few messages and configure a callback
// action for each one.
std::vector<gc::future<void>> ids;
for (int i = 0; i < 5; i++) {
  auto id = publisher.Publish(pubsub::MessageBuilder().SetData("Hi!").Build())
                .then([](gc::future<gc::StatusOr<std::string>> f) {
                  auto id = f.get();
                  if (!id) {
                    std::cout << "Error in publish: " << id.status() << "\n";
                    return;
                  }
                  std::cout << "Sent message with id: (" << *id << ")\n";
                });
  ids.push_back(std::move(id));
}
// Block until the messages are actually sent.
for (auto& id : ids) id.get();

編譯並執行範例：

cd cpp-samples/pubsub-open-telemetry
bazel run //:quickstart -- $(gcloud config get project) my-topic

執行這個範例後，您會在控制台中看到下列幾行輸出內容。

Sent message with id: (9095112996778043)
Sent message with id: (9095112996778044)
Sent message with id: (9095112996778045)
Sent message with id: (9095112996778046)
Sent message with id: (9095112996778047)

查看追蹤記錄

前往 Google Cloud 控制台的「Trace Explorer」頁面：

前往「Trace explorer」(Trace 探索工具)

您也可以透過搜尋列找到這個頁面。

清除所用資源

為了避免系統向您的 Google Cloud 帳戶收取本頁面所用資源的費用，請按照下列步驟操作。

刪除範例建立的主題：
```
gcloud pubsub topics delete my-topic
```

後續步驟

進一步瞭解 C++ 和 OpenTelemetry。
查看更多 C++ 範例。
進一步瞭解 Pub/Sub API。
試試更多 C++ Pub/Sub OpenTelemetry 範例。