Unless otherwise configured, the client libraries use Application Default Credentials 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 The 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::workstations_v1::WorkstationsClient(
google::cloud::workstations_v1::MakeWorkstationsConnection(options));
}
[[["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 2025-08-14 UTC."],[[["\u003cp\u003eThis webpage provides documentation for overriding default authentication credentials when using Google Cloud client libraries.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the documentation is 2.37.0-rc, with many previous versions available for reference.\u003c/p\u003e\n"],["\u003cp\u003eThe example demonstrates how to override the default authentication by explicitly loading a service account key file using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe default authentication for Google Cloud services is \u003ca href=\"https://cloud.google.com/docs/authentication#adc\"\u003eApplication Default Credentials\u003c/a\u003e, which can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eFor details 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 objects, refer to the \u003ca href=\"https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html\"\u003eAuthentication Components\u003c/a\u003e documentation.\u003c/p\u003e\n"]]],[],null,["Version latestkeyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/workstations/latest/workstations-override-authentication)\n- [2.41.0](/cpp/docs/reference/workstations/2.41.0/workstations-override-authentication)\n- [2.40.0](/cpp/docs/reference/workstations/2.40.0/workstations-override-authentication)\n- [2.39.0](/cpp/docs/reference/workstations/2.39.0/workstations-override-authentication)\n- [2.38.0](/cpp/docs/reference/workstations/2.38.0/workstations-override-authentication)\n- [2.37.0](/cpp/docs/reference/workstations/2.37.0/workstations-override-authentication)\n- [2.36.0](/cpp/docs/reference/workstations/2.36.0/workstations-override-authentication)\n- [2.35.0](/cpp/docs/reference/workstations/2.35.0/workstations-override-authentication)\n- [2.34.0](/cpp/docs/reference/workstations/2.34.0/workstations-override-authentication)\n- [2.33.0](/cpp/docs/reference/workstations/2.33.0/workstations-override-authentication)\n- [2.32.0](/cpp/docs/reference/workstations/2.32.0/workstations-override-authentication)\n- [2.31.0](/cpp/docs/reference/workstations/2.31.0/workstations-override-authentication)\n- [2.30.0](/cpp/docs/reference/workstations/2.30.0/workstations-override-authentication)\n- [2.29.0](/cpp/docs/reference/workstations/2.29.0/workstations-override-authentication)\n- [2.28.0](/cpp/docs/reference/workstations/2.28.0/workstations-override-authentication)\n- [2.27.0](/cpp/docs/reference/workstations/2.27.0/workstations-override-authentication)\n- [2.26.0](/cpp/docs/reference/workstations/2.26.0/workstations-override-authentication)\n- [2.25.1](/cpp/docs/reference/workstations/2.25.1/workstations-override-authentication)\n- [2.24.0](/cpp/docs/reference/workstations/2.24.0/workstations-override-authentication)\n- [2.23.0](/cpp/docs/reference/workstations/2.23.0/workstations-override-authentication)\n- [2.22.1](/cpp/docs/reference/workstations/2.22.1/workstations-override-authentication)\n- [2.21.0](/cpp/docs/reference/workstations/2.21.0/workstations-override-authentication)\n- [2.20.0](/cpp/docs/reference/workstations/2.20.0/workstations-override-authentication)\n- [2.19.0](/cpp/docs/reference/workstations/2.19.0/workstations-override-authentication)\n- [2.18.0](/cpp/docs/reference/workstations/2.18.0/workstations-override-authentication)\n- [2.17.0](/cpp/docs/reference/workstations/2.17.0/workstations-override-authentication)\n- [2.16.0](/cpp/docs/reference/workstations/2.16.0/workstations-override-authentication)\n- [2.15.1](/cpp/docs/reference/workstations/2.15.1/workstations-override-authentication)\n- [2.14.0](/cpp/docs/reference/workstations/2.14.0/workstations-override-authentication)\n- [2.13.0](/cpp/docs/reference/workstations/2.13.0/workstations-override-authentication)\n- [2.12.0](/cpp/docs/reference/workstations/2.12.0/workstations-override-authentication)\n- [2.11.0](/cpp/docs/reference/workstations/2.11.0/workstations-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::workstations_v1::WorkstationsClient(\n google::cloud::workstations_v1::MakeWorkstationsConnection(options));\n }\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."]]