Unless otherwise configured, the client libraries useApplication Default Credentialsto authenticate with Google Cloud Services. While this works for most applications, in some cases you may need to override this default. You can do so by providing theUnifiedCredentialsOptionThe following example shows how to explicitly load a service account key file:
[](std::string const& keyfile) {
auto is = std::ifstream(keyfile);
is.exceptions(std::ios::badbit); // Minimal error handling in examples
auto contents = std::string(std::istreambuf_iterator<char>(is.rdbuf()), {});
auto options =
google::cloud::Options{}.set<google::cloud::UnifiedCredentialsOption>(
google::cloud::MakeServiceAccountCredentials(contents));
return google::cloud::cloudbuild_v1::CloudBuildClient(
google::cloud::cloudbuild_v1::MakeCloudBuildConnection(options));
}
Follow these links to find examples for other*Clientclasses:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis document provides versioned documentation for the Google Cloud Build C++ client library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe primary focus of this content is on how to override the default Application Default Credentials (ADC) for authentication with Google Cloud Services, using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eAn example is provided demonstrating how to load a service account key file explicitly, which is relevant for use cases that require overriding default authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe document includes links to examples for \u003ccode\u003ecloudbuild_v1::CloudBuildClient\u003c/code\u003e and \u003ccode\u003ecloudbuild_v2::RepositoryManagerClient\u003c/code\u003e to show how to use the override.\u003c/p\u003e\n"],["\u003cp\u003eIt also recommends consulting the "Best practices for managing service account keys" guide and links to the "Authentication Components" section for more details on credential creation.\u003c/p\u003e\n"]]],[],null,["Version 2.21.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/cloudbuild/latest/cloudbuild-override-authentication)\n- [2.41.0](/cpp/docs/reference/cloudbuild/2.41.0/cloudbuild-override-authentication)\n- [2.40.0](/cpp/docs/reference/cloudbuild/2.40.0/cloudbuild-override-authentication)\n- [2.39.0](/cpp/docs/reference/cloudbuild/2.39.0/cloudbuild-override-authentication)\n- [2.38.0](/cpp/docs/reference/cloudbuild/2.38.0/cloudbuild-override-authentication)\n- [2.37.0](/cpp/docs/reference/cloudbuild/2.37.0/cloudbuild-override-authentication)\n- [2.36.0](/cpp/docs/reference/cloudbuild/2.36.0/cloudbuild-override-authentication)\n- [2.35.0](/cpp/docs/reference/cloudbuild/2.35.0/cloudbuild-override-authentication)\n- [2.34.0](/cpp/docs/reference/cloudbuild/2.34.0/cloudbuild-override-authentication)\n- [2.33.0](/cpp/docs/reference/cloudbuild/2.33.0/cloudbuild-override-authentication)\n- [2.32.0](/cpp/docs/reference/cloudbuild/2.32.0/cloudbuild-override-authentication)\n- [2.31.0](/cpp/docs/reference/cloudbuild/2.31.0/cloudbuild-override-authentication)\n- [2.30.0](/cpp/docs/reference/cloudbuild/2.30.0/cloudbuild-override-authentication)\n- [2.29.0](/cpp/docs/reference/cloudbuild/2.29.0/cloudbuild-override-authentication)\n- [2.28.0](/cpp/docs/reference/cloudbuild/2.28.0/cloudbuild-override-authentication)\n- [2.27.0](/cpp/docs/reference/cloudbuild/2.27.0/cloudbuild-override-authentication)\n- [2.26.0](/cpp/docs/reference/cloudbuild/2.26.0/cloudbuild-override-authentication)\n- [2.25.1](/cpp/docs/reference/cloudbuild/2.25.1/cloudbuild-override-authentication)\n- [2.24.0](/cpp/docs/reference/cloudbuild/2.24.0/cloudbuild-override-authentication)\n- [2.23.0](/cpp/docs/reference/cloudbuild/2.23.0/cloudbuild-override-authentication)\n- [2.22.1](/cpp/docs/reference/cloudbuild/2.22.1/cloudbuild-override-authentication)\n- [2.21.0](/cpp/docs/reference/cloudbuild/2.21.0/cloudbuild-override-authentication)\n- [2.20.0](/cpp/docs/reference/cloudbuild/2.20.0/cloudbuild-override-authentication)\n- [2.19.0](/cpp/docs/reference/cloudbuild/2.19.0/cloudbuild-override-authentication)\n- [2.18.0](/cpp/docs/reference/cloudbuild/2.18.0/cloudbuild-override-authentication)\n- [2.17.0](/cpp/docs/reference/cloudbuild/2.17.0/cloudbuild-override-authentication)\n- [2.16.0](/cpp/docs/reference/cloudbuild/2.16.0/cloudbuild-override-authentication)\n- [2.15.1](/cpp/docs/reference/cloudbuild/2.15.1/cloudbuild-override-authentication)\n- [2.14.0](/cpp/docs/reference/cloudbuild/2.14.0/cloudbuild-override-authentication)\n- [2.13.0](/cpp/docs/reference/cloudbuild/2.13.0/cloudbuild-override-authentication)\n- [2.12.0](/cpp/docs/reference/cloudbuild/2.12.0/cloudbuild-override-authentication)\n- [2.11.0](/cpp/docs/reference/cloudbuild/2.11.0/cloudbuild-override-authentication) \n\nHow to Override the Authentication Credentials\n==============================================\n\nUnless otherwise configured, the client libraries use [Application Default Credentials](https://cloud.google.com/docs/authentication#adc) to authenticate with Google Cloud Services. While this works for most applications, in some cases you may need to override this default. You can do so by providing the [UnifiedCredentialsOption](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1UnifiedCredentialsOption.html) The following example shows how to explicitly load a service account key file: \n\n [](std::string const& keyfile) {\n auto is = std::ifstream(keyfile);\n is.exceptions(std::ios::badbit); // Minimal error handling in examples\n auto contents = std::string(std::istreambuf_iterator\u003cchar\u003e(is.rdbuf()), {});\n auto options =\n google::cloud::Options{}.set\u003cgoogle::cloud::UnifiedCredentialsOption\u003e(\n google::cloud::MakeServiceAccountCredentials(contents));\n return google::cloud::cloudbuild_v1::CloudBuildClient(\n google::cloud::cloudbuild_v1::MakeCloudBuildConnection(options));\n }\n\nFollow these links to find examples for other `*Client` classes:\n\n- [`cloudbuild_v1::CloudBuildClient`](/cpp/docs/reference/cloudbuild/2.21.0/cloudbuild_v1_1_1CloudBuildClient-service-account-snippet)\n- [`cloudbuild_v2::RepositoryManagerClient`](/cpp/docs/reference/cloudbuild/2.21.0/cloudbuild_v2_1_1RepositoryManagerClient-service-account-snippet)\n\nKeep in mind that we chose this as an example because it is relatively easy to understand. Consult the [Best practices for managing service account keys](https://cloud.google.com/iam/docs/best-practices-for-managing-service-account-keys) guide for more details.\n\n###### See Also\n\n[Authentication Components](https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html) - for more information on the factory functions to create [`google::cloud::Credentials`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1Credentials.html) objects."]]