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::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 2025-09-04 UTC."],[[["\u003cp\u003eThis webpage provides documentation for overriding default authentication credentials when using Google Cloud client libraries, specifically focusing on workstations.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version is 2.37.0-rc, with a comprehensive history of prior versions ranging back to 2.11.0 also provided on this page.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries employ Application Default Credentials for authenticating with Google Cloud Services, but this can be overridden using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eAn example demonstrates loading a service account key file to override the default authentication, leveraging \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe page also references additional resources, such as best practices for managing service account keys and the "Authentication Components" documentation for creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,["Version 2.33.0keyboard_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."]]