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::datafusion_v1::DataFusionClient(
google::cloud::datafusion_v1::MakeDataFusionConnection(options));
}
[[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page provides documentation for overriding default authentication credentials when interacting with Google Cloud Services.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e can be utilized to override the Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eAn example demonstrates loading a service account key file to override default credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release of documentation is version 2.37.0-rc, with multiple previous versions also being documented and accessible.\u003c/p\u003e\n"],["\u003cp\u003eUsers should consult the best practices guide for managing service account keys for more robust security practices.\u003c/p\u003e\n"]]],[],null,[]]
