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::bigquery_analyticshub_v1::AnalyticsHubServiceClient(
google::cloud::bigquery_analyticshub_v1::
MakeAnalyticsHubServiceConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 multiple previous versions of the BigQuery C++ client libraries are available, starting from version 2.11.0 up to the most recently released version, 2.36.0.\u003c/p\u003e\n"],["\u003cp\u003eBy default, the client libraries authenticate with Google Cloud Services using Application Default Credentials, which can be overridden in certain cases.\u003c/p\u003e\n"],["\u003cp\u003eOverriding default authentication can be achieved by using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated by explicitly loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation provides links to examples for overriding authentication with various \u003ccode\u003e*Client\u003c/code\u003e classes, including \u003ccode\u003eAnalyticsHubServiceClient\u003c/code\u003e, \u003ccode\u003eMetastoreServiceClient\u003c/code\u003e, and others.\u003c/p\u003e\n"],["\u003cp\u003eRefer to the "Best practices for managing service account keys" guide for detailed information on service account key management and the "Authentication Components" for additional information on the creation of \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,[]]
