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::kms_inventory_v1::KeyDashboardServiceClient(
google::cloud::kms_inventory_v1::MakeKeyDashboardServiceConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 version-specific details and examples on how to override default authentication credentials when using Google Cloud client libraries, with the latest release being 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe content focuses on the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e to override the default \u003ca href=\"https://cloud.google.com/docs/authentication#adc\"\u003eApplication Default Credentials\u003c/a\u003e for authenticating with Google Cloud services.\u003c/p\u003e\n"],["\u003cp\u003eAn example is provided to illustrate how to load a service account key file explicitly for authentication, which can be used with various client classes like \u003ccode\u003eKeyDashboardServiceClient\u003c/code\u003e, \u003ccode\u003eKeyTrackingServiceClient\u003c/code\u003e, \u003ccode\u003eEkmServiceClient\u003c/code\u003e, and \u003ccode\u003eKeyManagementServiceClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe examples provided use relatively simple error handling and link to a best practices guide for managing service account keys, offering further assistance.\u003c/p\u003e\n"],["\u003cp\u003eThe document also links to the "Authentication Components" section for more details on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, providing more in depth explanations.\u003c/p\u003e\n"]]],[],null,[]]
