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::policysimulator_v1::SimulatorClient(
google::cloud::policysimulator_v1::MakeSimulatorConnection(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 2025-05-07 UTC."],[[["This page provides documentation for the Policy Simulator, with version 2.37.0-rc being the latest release candidate and version 2.22.1 the current version, alongside a comprehensive list of prior versions and their respective documentation."],["The client libraries typically utilize Application Default Credentials for authentication with Google Cloud Services, however, this behavior can be overridden."],["To override the default authentication, you can use the `UnifiedCredentialsOption`, demonstrated in an example that shows how to load a service account key file."],["The guide recommends reviewing the \"Best practices for managing service account keys\" for in depth information, and the \"Authentication Components\" section for creating `google::cloud::Credentials` objects."]]],[]]
