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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis page details how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services when using C++ client libraries.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version documented is 2.37.0-rc, with a list of previous versions available, from 2.36.0 down to 2.11.0, each with their own respective link to their own documentation.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication can be overridden by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated by the example that shows how to load a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples are provided for \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 classes.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on managing service account keys and creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, refer to the provided links for best practices and authentication components.\u003c/p\u003e\n"]]],[],null,[]]
