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::workflows_executions_v1::ExecutionsClient(
google::cloud::workflows_executions_v1::MakeExecutionsConnection(
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 page details how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services, which is necessary in certain cases.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version covered is 2.37.0-rc, and the page provides links to documentation for multiple preceding versions, including 2.29.0, which is the current version of focus.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default credentials by using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and loading a service account key file, as demonstrated in the code example.\u003c/p\u003e\n"],["\u003cp\u003eThe page also includes links to example code snippets for \u003ccode\u003eworkflows_executions_v1::ExecutionsClient\u003c/code\u003e and \u003ccode\u003eworkflows_v1::WorkflowsClient\u003c/code\u003e, detailing their usage with service account credentials.\u003c/p\u003e\n"],["\u003cp\u003eFor detailed guidance on managing service account keys, refer to the provided link to the "Best practices for managing service account keys" guide, and for more information on the factory functions used to create credentials.\u003c/p\u003e\n"]]],[],null,["Version 2.29.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/workflows/latest/workflows-override-authentication)\n- [2.41.0](/cpp/docs/reference/workflows/2.41.0/workflows-override-authentication)\n- [2.40.0](/cpp/docs/reference/workflows/2.40.0/workflows-override-authentication)\n- [2.39.0](/cpp/docs/reference/workflows/2.39.0/workflows-override-authentication)\n- [2.38.0](/cpp/docs/reference/workflows/2.38.0/workflows-override-authentication)\n- [2.37.0](/cpp/docs/reference/workflows/2.37.0/workflows-override-authentication)\n- [2.36.0](/cpp/docs/reference/workflows/2.36.0/workflows-override-authentication)\n- [2.35.0](/cpp/docs/reference/workflows/2.35.0/workflows-override-authentication)\n- [2.34.0](/cpp/docs/reference/workflows/2.34.0/workflows-override-authentication)\n- [2.33.0](/cpp/docs/reference/workflows/2.33.0/workflows-override-authentication)\n- [2.32.0](/cpp/docs/reference/workflows/2.32.0/workflows-override-authentication)\n- [2.31.0](/cpp/docs/reference/workflows/2.31.0/workflows-override-authentication)\n- [2.30.0](/cpp/docs/reference/workflows/2.30.0/workflows-override-authentication)\n- [2.29.0](/cpp/docs/reference/workflows/2.29.0/workflows-override-authentication)\n- [2.28.0](/cpp/docs/reference/workflows/2.28.0/workflows-override-authentication)\n- [2.27.0](/cpp/docs/reference/workflows/2.27.0/workflows-override-authentication)\n- [2.26.0](/cpp/docs/reference/workflows/2.26.0/workflows-override-authentication)\n- [2.25.1](/cpp/docs/reference/workflows/2.25.1/workflows-override-authentication)\n- [2.24.0](/cpp/docs/reference/workflows/2.24.0/workflows-override-authentication)\n- [2.23.0](/cpp/docs/reference/workflows/2.23.0/workflows-override-authentication)\n- [2.22.1](/cpp/docs/reference/workflows/2.22.1/workflows-override-authentication)\n- [2.21.0](/cpp/docs/reference/workflows/2.21.0/workflows-override-authentication)\n- [2.20.0](/cpp/docs/reference/workflows/2.20.0/workflows-override-authentication)\n- [2.19.0](/cpp/docs/reference/workflows/2.19.0/workflows-override-authentication)\n- [2.18.0](/cpp/docs/reference/workflows/2.18.0/workflows-override-authentication)\n- [2.17.0](/cpp/docs/reference/workflows/2.17.0/workflows-override-authentication)\n- [2.16.0](/cpp/docs/reference/workflows/2.16.0/workflows-override-authentication)\n- [2.15.1](/cpp/docs/reference/workflows/2.15.1/workflows-override-authentication)\n- [2.14.0](/cpp/docs/reference/workflows/2.14.0/workflows-override-authentication)\n- [2.13.0](/cpp/docs/reference/workflows/2.13.0/workflows-override-authentication)\n- [2.12.0](/cpp/docs/reference/workflows/2.12.0/workflows-override-authentication)\n- [2.11.0](/cpp/docs/reference/workflows/2.11.0/workflows-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::workflows_executions_v1::ExecutionsClient(\n google::cloud::workflows_executions_v1::MakeExecutionsConnection(\n options));\n }\n\nFollow these links to find examples for other `*Client` classes:\n\n- [`workflows_executions_v1::ExecutionsClient`](/cpp/docs/reference/workflows/2.29.0/workflows_executions_v1_1_1ExecutionsClient-service-account-snippet)\n- [`workflows_v1::WorkflowsClient`](/cpp/docs/reference/workflows/2.29.0/workflows_v1_1_1WorkflowsClient-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."]]