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 document provides a guide on how to override default authentication credentials when using Google Cloud Client Libraries, using service account key files as an example.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version is 2.37.0-rc, and the content includes documentation for versions ranging from 2.11.0 to 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe default authentication for Google Cloud services uses Application Default Credentials, which can be overridden by utilizing \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe document provides code examples for loading a service account key file to override default authentication, including links to example for \u003ccode\u003eManagedNotebookServiceClient\u003c/code\u003e and \u003ccode\u003eNotebookServiceClient\u003c/code\u003e classes.\u003c/p\u003e\n"],["\u003cp\u003eBest practices for managing service account keys should be consulted, with more information on how to create \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects found in the Authentication Components section.\u003c/p\u003e\n"]]],[],null,["Version 2.32.0keyboard_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/2.32.0/notebooks_v1_1_1ManagedNotebookServiceClient-service-account-snippet)\n- [`notebooks_v1::NotebookServiceClient`](/cpp/docs/reference/notebooks/2.32.0/notebooks_v1_1_1NotebookServiceClient-service-account-snippet)\n- [`notebooks_v2::NotebookServiceClient`](/cpp/docs/reference/notebooks/2.32.0/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."]]