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::automl_v1::AutoMlClient(
google::cloud::automl_v1::MakeAutoMlConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 latest release candidate version is 2.37.0-rc, and it is located at /cpp/docs/reference/automl/latest/automl-override-authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe document lists multiple versions of the AutoML client library, ranging from version 2.11.0 to 2.36.0, along with the current release candidate, all with information regarding overriding authentication.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication with Google Cloud Services is done using Application Default Credentials, but this can be overridden using the UnifiedCredentialsOption, allowing you to load a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples for other client classes, such as \u003ccode\u003eautoml_v1::AutoMlClient\u003c/code\u003e and \u003ccode\u003eautoml_v1::PredictionServiceClient\u003c/code\u003e, are available via provided links for version 2.20.0.\u003c/p\u003e\n"],["\u003cp\u003eThe document recommends the guide "Best practices for managing service account keys" and provides a link to "Authentication Components" for further information.\u003c/p\u003e\n"]]],[],null,[]]
