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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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, with version 2.36.0 being the most recent stable release, and numerous prior versions, dating back to 2.11.0, available for reference.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries generally employ Application Default Credentials for authentication with Google Cloud Services, but you can override this default if needed.\u003c/p\u003e\n"],["\u003cp\u003eOverriding the default authentication can be achieved by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated with an example that loads a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eautoml_v1::AutoMlClient\u003c/code\u003e and \u003ccode\u003eautoml_v1::PredictionServiceClient\u003c/code\u003e classes have available examples for service account authentication, with a recommendation to review best practices for managing service account keys.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on creating credentials objects, consult the Authentication Components documentation.\u003c/p\u003e\n"]]],[],null,[]]
