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::metastore_v1::DataprocMetastoreClient(
google::cloud::metastore_v1::MakeDataprocMetastoreConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 version available is 2.37.0-rc, with numerous older versions available ranging from 2.36.0 down to 2.13.0.\u003c/p\u003e\n"],["\u003cp\u003eClient libraries generally authenticate with Google Cloud Services using Application Default Credentials, but this default can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eYou can override default authentication by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and explicitly loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples for overriding authentication using a service account are available for \u003ccode\u003emetastore_v1::DataprocMetastoreClient\u003c/code\u003e and \u003ccode\u003emetastore_v1::DataprocMetastoreFederationClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eFor detailed guidance on service account key management, refer to the Best practices for managing service account keys guide, and for more information on factory functions for creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, see the Authentication Components documentation.\u003c/p\u003e\n"]]],[],null,[]]
