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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page provides documentation for overriding default authentication credentials when using Google Cloud client libraries, which typically rely on Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated with an example of loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe page contains links to examples for different \u003ccode\u003e*Client\u003c/code\u003e classes, specifically \u003ccode\u003ekms_inventory_v1::KeyDashboardServiceClient\u003c/code\u003e, \u003ccode\u003ekms_inventory_v1::KeyTrackingServiceClient\u003c/code\u003e, \u003ccode\u003ekms_v1::EkmServiceClient\u003c/code\u003e, and \u003ccode\u003ekms_v1::KeyManagementServiceClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation includes a reference to the "Best practices for managing service account keys" guide and the "Authentication Components" section for more details.\u003c/p\u003e\n"],["\u003cp\u003eMultiple versions of the documentation are available, ranging from the latest \u003ccode\u003e2.37.0-rc\u003c/code\u003e down to \u003ccode\u003e2.10.1\u003c/code\u003e.\u003c/p\u003e\n"]]],[],null,[]]
