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::serviceusage_v1::ServiceUsageClient(
google::cloud::serviceusage_v1::MakeServiceUsageConnection(options));
}
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-03-14 UTC."],[[["This webpage provides documentation for various versions of the C++ Service Usage client library, ranging from version 2.11.0 to 2.37.0-rc, with the latter being the latest release candidate."],["The client libraries typically use Application Default Credentials for authentication with Google Cloud Services, but this default behavior can be overridden if needed."],["Overriding authentication involves providing a `UnifiedCredentialsOption`, as demonstrated with an example that uses a service account key file for authentication."],["Users can find additional details on managing service account keys in the provided guide and learn more about the factory functions for `google::cloud::Credentials` objects in the Authentication Components section."]]],[]]