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::billing_budgets_v1::BudgetServiceClient(
google::cloud::billing_budgets_v1::MakeBudgetServiceConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page details how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services, which is done by providing a \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe content provides a code example demonstrating how to explicitly load a service account key file using \u003ccode\u003egoogle::cloud::MakeServiceAccountCredentials\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation includes links to examples for \u003ccode\u003ebilling_budgets_v1::BudgetServiceClient\u003c/code\u003e, \u003ccode\u003ebilling_v1::CloudBillingClient\u003c/code\u003e, and \u003ccode\u003ebilling_v1::CloudCatalogClient\u003c/code\u003e for overriding authentication credentials.\u003c/p\u003e\n"],["\u003cp\u003eA range of version documentation is available, from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe content also references the importance of reviewing best practices for managing service accounts keys, as well as referencing the Authentication Components for more information on credential objects.\u003c/p\u003e\n"]]],[],null,[]]
