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 2025-03-14 UTC."],[[["The latest release candidate version for the policysimulator is 2.37.0-rc."],["This page documents different versions of the policysimulator, with versions ranging from 2.15.1 up to 2.37.0-rc, with a primary focus on how to override the default authentication settings."],["Client libraries use Application Default Credentials for authentication, but users can override this by using the `UnifiedCredentialsOption`."],["Overriding the default authentication is demonstrated by explicitly loading a service account key file, as seen in the provided code example."],["The `Authentication Components` page provides more information on creating `google::cloud::Credentials` objects, and you should review the best practices guide for managing service account keys."]]],[]]
