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, which typically rely on Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated with an example of loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe document covers a range of versions for the \u003ccode\u003enotebooks\u003c/code\u003e service, from version 2.11.0 up to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eSpecific examples for overriding authentication are provided for \u003ccode\u003eManagedNotebookServiceClient\u003c/code\u003e and \u003ccode\u003eNotebookServiceClient\u003c/code\u003e in both \u003ccode\u003enotebooks_v1\u003c/code\u003e and \u003ccode\u003enotebooks_v2\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe document directs users to best practices for managing service accounts keys and information on factory functions to create \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,["Version 2.29.0keyboard_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/2.29.0/notebooks_v1_1_1ManagedNotebookServiceClient-service-account-snippet)\n- [`notebooks_v1::NotebookServiceClient`](/cpp/docs/reference/notebooks/2.29.0/notebooks_v1_1_1NotebookServiceClient-service-account-snippet)\n- [`notebooks_v2::NotebookServiceClient`](/cpp/docs/reference/notebooks/2.29.0/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."]]