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 details how to override the default authentication credentials for Google Cloud services, which typically use Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version is 2.37.0-rc, with the most recent stable version being 2.36.0, and there are several versions available that are listed.\u003c/p\u003e\n"],["\u003cp\u003eOverriding the default credentials can be accomplished by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing a service account key file, as shown in the provided example code.\u003c/p\u003e\n"],["\u003cp\u003eExamples for \u003ccode\u003ecloudbuild_v1::CloudBuildClient\u003c/code\u003e and \u003ccode\u003ecloudbuild_v2::RepositoryManagerClient\u003c/code\u003e are provided, demonstrating how to apply service account credentials to them.\u003c/p\u003e\n"],["\u003cp\u003eThe provided documentation links to the \u003ccode\u003eAuthentication Components\u003c/code\u003e page for more information on creating \u003ca href=\"https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1Credentials.html\"\u003e\u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e\u003c/a\u003e and it is recommended to check out the best practices for managing service account keys.\u003c/p\u003e\n"]]],[],null,["Version 2.23.0keyboard_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/2.23.0/cloudbuild_v1_1_1CloudBuildClient-service-account-snippet)\n- [`cloudbuild_v2::RepositoryManagerClient`](/cpp/docs/reference/cloudbuild/2.23.0/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."]]