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 serviceusage API, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc."],["The default authentication method for client libraries is Application Default Credentials, but you can override this to use service account key files."],["To override authentication, you can use the `UnifiedCredentialsOption` and `MakeServiceAccountCredentials` functions, and load a service account key file."],["The example provided demonstrates loading a service account key file to override authentication credentials, which can be set with the option, while the best practice guide should be consulted for more details."],["There is a section that links to additional documentation for further details on `google::cloud::Credentials` objects and the factory functions that create them."]]],[]]
