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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-07-09 UTC."],[[["This document provides information on how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services."],["You can override the default credentials by providing the `UnifiedCredentialsOption`, as demonstrated with an example of loading a service account key file."],["Examples for other client classes, such as `billing_budgets_v1::BudgetServiceClient`, `billing_v1::CloudBillingClient`, and `billing_v1::CloudCatalogClient`, are also provided."],["The latest version available for the service is 2.37.0-rc, and links to previous versions, starting with 2.36.0 and ending with 2.11.0, are provided, all of which link to a document containing information regarding billing-override-authentication."],["The document references the \"Best practices for managing service account keys\" guide and the \"Authentication Components\" documentation for further information."]]],[]]
