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::run_v2::ExecutionsClient(
google::cloud::run_v2::MakeExecutionsConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThe webpage details how to override default authentication credentials, which typically use Application Default Credentials, for Google Cloud Services.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default credentials by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing a service account key file, as demonstrated in the provided code example.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation provides versioned links for various versions of \u003ccode\u003erun-override-authentication\u003c/code\u003e, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eExamples for overriding credentials are also provided for several \u003ccode\u003e*Client\u003c/code\u003e classes including \u003ccode\u003erun_v2::ExecutionsClient\u003c/code\u003e, \u003ccode\u003erun_v2::JobsClient\u003c/code\u003e, \u003ccode\u003erun_v2::RevisionsClient\u003c/code\u003e, \u003ccode\u003erun_v2::ServicesClient\u003c/code\u003e, and \u003ccode\u003erun_v2::TasksClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe page also links to best practices for managing service account keys and to more information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,[]]
