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::RevisionsClient(
google::cloud::run_v2::MakeRevisionsConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 documents various versions of the run-override-authentication feature, with version 2.37.0-rc being the latest, and version 2.11.0 being the lowest present in this content.\u003c/p\u003e\n"],["\u003cp\u003eThe default authentication method for client libraries is Application Default Credentials, but this can be overridden in certain situations.\u003c/p\u003e\n"],["\u003cp\u003eOverriding the default authentication involves utilizing \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated by the provided code example for loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples for overriding authentication are available for \u003ccode\u003erun_v2::RevisionsClient\u003c/code\u003e and \u003ccode\u003erun_v2::ServicesClient\u003c/code\u003e classes.\u003c/p\u003e\n"],["\u003cp\u003eFor comprehensive information on managing service account keys, refer to the guide on Best practices for managing service account keys, and for more information on creating credentials objects, see the Authentication Components section.\u003c/p\u003e\n"]]],[],null,[]]
