Cloud Pub/Sub C++ Client Library (original) (raw)

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Cloud Pub/Sub C++ Client Library

The Cloud Pub/Sub C++ Client library offers types and functions to use Cloud Pub/Sub from C++ applications.

Quickstart

The following "Hello World" program should give you a sense of how to use the library.

#include "google/cloud/pubsub/publisher.h"
#include <iostream>

int main(int argc, char* argv[]) try {
  if (argc != 3) {
    std::cerr << "Usage: " << argv[0] << " <project-id> <topic-id>\n";
    return 1;
  }

  std::string const project_id = argv[1];
  std::string const topic_id = argv[2];

  // Create a namespace alias to make the code easier to read.
  namespace pubsub = ::google:☁️:pubsub;

  auto publisher = pubsub::Publisher(
      pubsub::MakePublisherConnection(pubsub::Topic(project_id, topic_id)));
  auto id =
      publisher
          .Publish(pubsub::MessageBuilder{}.SetData("Hello World!").Build())
          .get();
  if (!id) throw std::move(id).status();
  std::cout << "Hello World published with id=" << *id << "\n";

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

More Information

• Publisher::Publish() - to efficiently publish Pub/Sub messages.
• BlockingPublisher::Publish() - to publish a single Pub/Sub messages.
• Subscriber::Subscribe() - to asynchronous receive Pub/Sub messages.
• Subscriber::Pull() - to receive a single Pub/Sub messages.
• Error Handling to learn how the library reports run-time errors.
• Environment Variables for environment variables affecting the library. Some of these environment variables enable logging to the console. This can be an effective approach to diagnose runtime problems.
• Override the default endpoint
• Override the authentication configuration
• Override Retry, Backoff, and Idempotency Policies
• Override the default universe domain
• Testing your Cloud Pub/Sub publisher application with googlemock shows how to write tests mocking Publisher
• Testing your Cloud Pub/Sub subscriber application with googlemock shows how to write tests mocking Subscriber
• The Setting up your development environment guide describes how to set up a C++ development environment in various platforms, including the Google Cloud C++ client libraries.

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Last updated 2026-03-31 UTC.