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::notebooks_v1::ManagedNotebookServiceClient(
google::cloud::notebooks_v1::MakeManagedNotebookServiceConnection(
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 provides documentation for overriding default authentication credentials when using Google Cloud client libraries, with version-specific information available.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate is version 2.37.0-rc, and there are many previous versions, starting from 2.36.0 going all the way down to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eThe example on the page shows how to override the default credentials by loading a service account key file via \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eExamples for overriding credentials are provided for \u003ccode\u003enotebooks_v1::ManagedNotebookServiceClient\u003c/code\u003e, \u003ccode\u003enotebooks_v1::NotebookServiceClient\u003c/code\u003e, and \u003ccode\u003enotebooks_v2::NotebookServiceClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eFor additional details and best practices for managing service account keys, a link to the official Google Cloud guide is included.\u003c/p\u003e\n"]]],[],null,["Version 2.19.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/notebooks/latest/notebooks-override-authentication)\n- [2.41.0](/cpp/docs/reference/notebooks/2.41.0/notebooks-override-authentication)\n- [2.40.0](/cpp/docs/reference/notebooks/2.40.0/notebooks-override-authentication)\n- [2.39.0](/cpp/docs/reference/notebooks/2.39.0/notebooks-override-authentication)\n- [2.38.0](/cpp/docs/reference/notebooks/2.38.0/notebooks-override-authentication)\n- [2.37.0](/cpp/docs/reference/notebooks/2.37.0/notebooks-override-authentication)\n- [2.36.0](/cpp/docs/reference/notebooks/2.36.0/notebooks-override-authentication)\n- [2.35.0](/cpp/docs/reference/notebooks/2.35.0/notebooks-override-authentication)\n- [2.34.0](/cpp/docs/reference/notebooks/2.34.0/notebooks-override-authentication)\n- [2.33.0](/cpp/docs/reference/notebooks/2.33.0/notebooks-override-authentication)\n- [2.32.0](/cpp/docs/reference/notebooks/2.32.0/notebooks-override-authentication)\n- [2.31.0](/cpp/docs/reference/notebooks/2.31.0/notebooks-override-authentication)\n- [2.30.0](/cpp/docs/reference/notebooks/2.30.0/notebooks-override-authentication)\n- [2.29.0](/cpp/docs/reference/notebooks/2.29.0/notebooks-override-authentication)\n- [2.28.0](/cpp/docs/reference/notebooks/2.28.0/notebooks-override-authentication)\n- [2.27.0](/cpp/docs/reference/notebooks/2.27.0/notebooks-override-authentication)\n- [2.26.0](/cpp/docs/reference/notebooks/2.26.0/notebooks-override-authentication)\n- [2.25.1](/cpp/docs/reference/notebooks/2.25.1/notebooks-override-authentication)\n- [2.24.0](/cpp/docs/reference/notebooks/2.24.0/notebooks-override-authentication)\n- [2.23.0](/cpp/docs/reference/notebooks/2.23.0/notebooks-override-authentication)\n- [2.22.1](/cpp/docs/reference/notebooks/2.22.1/notebooks-override-authentication)\n- [2.21.0](/cpp/docs/reference/notebooks/2.21.0/notebooks-override-authentication)\n- [2.20.0](/cpp/docs/reference/notebooks/2.20.0/notebooks-override-authentication)\n- [2.19.0](/cpp/docs/reference/notebooks/2.19.0/notebooks-override-authentication)\n- [2.18.0](/cpp/docs/reference/notebooks/2.18.0/notebooks-override-authentication)\n- [2.17.0](/cpp/docs/reference/notebooks/2.17.0/notebooks-override-authentication)\n- [2.16.0](/cpp/docs/reference/notebooks/2.16.0/notebooks-override-authentication)\n- [2.15.1](/cpp/docs/reference/notebooks/2.15.1/notebooks-override-authentication)\n- [2.14.0](/cpp/docs/reference/notebooks/2.14.0/notebooks-override-authentication)\n- [2.13.0](/cpp/docs/reference/notebooks/2.13.0/notebooks-override-authentication)\n- [2.12.0](/cpp/docs/reference/notebooks/2.12.0/notebooks-override-authentication)\n- [2.11.0](/cpp/docs/reference/notebooks/2.11.0/notebooks-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::notebooks_v1::ManagedNotebookServiceClient(\n google::cloud::notebooks_v1::MakeManagedNotebookServiceConnection(\n options));\n }\n\nFollow these links to find examples for other `*Client` classes:\n\n- [`notebooks_v1::ManagedNotebookServiceClient`](/cpp/docs/reference/notebooks/2.19.0/notebooks_v1_1_1ManagedNotebookServiceClient-service-account-snippet)\n- [`notebooks_v1::NotebookServiceClient`](/cpp/docs/reference/notebooks/2.19.0/notebooks_v1_1_1NotebookServiceClient-service-account-snippet)\n- [`notebooks_v2::NotebookServiceClient`](/cpp/docs/reference/notebooks/2.19.0/notebooks_v2_1_1NotebookServiceClient-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."]]