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::optimization_v1::FleetRoutingClient(
google::cloud::optimization_v1::MakeFleetRoutingConnection(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 2025-03-05 UTC."],[[["This page provides documentation for overriding default authentication credentials in the C++ client libraries for Google Cloud services, covering versions from 2.11.0 up to the latest release candidate 2.37.0-rc."],["By default, the client libraries utilize Application Default Credentials for authentication, but users can override this behavior when needed."],["Overriding default credentials involves using `UnifiedCredentialsOption` and, as an example, it is shown how to explicitly load a service account key file using `MakeServiceAccountCredentials`."],["Users should consult the \"Best practices for managing service account keys\" guide for more detailed security information."],["For further information on creating `google::cloud::Credentials` objects, users can refer to the Authentication Components documentation."]]],[]]
