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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis page details how to override the default authentication credentials for Google Cloud services using the C++ client libraries.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the documentation is 2.37.0-rc, and this document includes a list of all previous versions, down to version 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eOverriding the default credentials is done by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and is exemplified by loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe page provides links to examples for \u003ccode\u003eautoml_v1::AutoMlClient\u003c/code\u003e and \u003ccode\u003eautoml_v1::PredictionServiceClient\u003c/code\u003e classes using service account keys.\u003c/p\u003e\n"],["\u003cp\u003eFor more information on managing service account keys and authentication components, consult the linked best practices guide and authentication components documentation, respectively.\u003c/p\u003e\n"]]],[],null,[]]
