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 2025-03-21 UTC."],[[["This page provides documentation for the Policy Simulator, specifically detailing how to override default authentication credentials, with a current focus on version 2.28.0 and a list of other versions, including the latest release candidate, 2.37.0-rc."],["The default authentication method for client libraries is Application Default Credentials, but users can override this by using the `UnifiedCredentialsOption` to explicitly define credentials."],["The provided example demonstrates loading credentials from a service account key file, using `MakeServiceAccountCredentials`, highlighting a simple method for credential management."],["For more robust and secure credential management practices, the document recommends consulting the \"Best practices for managing service account keys\" guide."],["The user is encouraged to review the provided link for \"Authentication Components\" to gain more information about factory functions that create `google::cloud::Credentials` objects."]]],[]]
