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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 guidance on overriding default authentication credentials when interacting with Google Cloud Services using client libraries.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version available is \u003ccode\u003e2.37.0-rc\u003c/code\u003e, but the document lists version options ranging from that down to \u003ccode\u003e2.10.1\u003c/code\u003e for the user to explore.\u003c/p\u003e\n"],["\u003cp\u003eBy utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, users can explicitly define how their client authenticates, as demonstrated through an example of loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe example provided focuses on creating a \u003ccode\u003eKeyDashboardServiceClient\u003c/code\u003e but has further linked examples for other client classes such as \u003ccode\u003eKeyTrackingServiceClient\u003c/code\u003e, \u003ccode\u003eEkmServiceClient\u003c/code\u003e, and \u003ccode\u003eKeyManagementServiceClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe document advises consulting the linked guide for best practices regarding service account key management and offers further information on \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects in the "Authentication Components" section.\u003c/p\u003e\n"]]],[],null,[]]
