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 for various versions ranging from 2.15.1 to 2.37.0-rc."],["The latest available version is 2.37.0-rc, with links to documentation for each version, allowing you to easily navigate through the different releases."],["Client libraries typically use Application Default Credentials (ADC) for authentication, but this behavior can be overridden when necessary, such as when needing to explicitly load a service account key file."],["Overriding the default authentication can be accomplished by using the UnifiedCredentialsOption, as demonstrated in the provided example code which illustrates how to load credentials from a key file."],["For more comprehensive information on managing service account keys and authentication components, users are directed to the \"Best practices for managing service account keys\" guide and the \"Authentication Components\" section, respectively."]]],[]]
