Unless otherwise configured, the client libraries use Application Default Credentials 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 The 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 *Client classes:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 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,[]]
