Google Cloud Storage C++ Client Library

The Google Cloud Storage (GCS) C++ Client library offers types and functions access GCS from C++ applications. It offers full access to the GCS API, including operations to list, read, write, and delete GCS objects and buckets . The library also provides functions to modify the IAM permissions on buckets, read and modify the metadata associated with objects and buckets, configure encryption keys, configure notifications via Cloud Pub/Sub, and change the access control list of object or buckets.

Quickstart

The following "Hello World" program should give you a taste of this library. This program is also used to illustrate how to incorporate the library into your project.

 #include "google/cloud/storage/client.h"
#include <iostream>
#include <string>

int main(int argc, char* argv[]) {
  if (argc != 2) {
    std::cerr << "Missing bucket name.\n";
    std::cerr << "Usage: quickstart <bucket-name>\n";
    return 1;
  }
  std::string const bucket_name = argv[1];

  // Create aliases to make the code easier to read.
  namespace gcs = ::google::cloud::storage;

  // Create a client to communicate with Google Cloud Storage. This client
  // uses the default configuration for authentication and project id.
  auto client = gcs::Client();

  auto writer = client.WriteObject(bucket_name, "quickstart.txt");
  writer << "Hello World!";
  writer.Close();
  if (!writer.metadata()) {
    std::cerr << "Error creating object: " << writer.metadata().status()
              << "\n";
    return 1;
  }
  std::cout << "Successfully created object: " << *writer.metadata() << "\n";

  auto reader = client.ReadObject(bucket_name, "quickstart.txt");
  if (!reader) {
    std::cerr << "Error reading object: " << reader.status() << "\n";
    return 1;
  }

  std::string contents{std::istreambuf_iterator<char>{reader}, {}};
  std::cout << contents << "\n";

  return 0;
} 

More Information

• ReadObject() - the function to read object data.
• WriteObject() - the function to write objects.
• InsertObject() - the function to write small objects.
• 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 the default retry policies
• Writing Tests with a Mock Client shows how to write tests mocking the Client class
• 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.