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 2025-04-02 UTC."],[[["This page lists various versions of the C++ optimization documentation, ranging from version 2.11.0 to the latest release candidate, 2.37.0-rc."],["The client libraries generally authenticate using Application Default Credentials, but this can be overridden."],["You can override the default authentication by providing the `UnifiedCredentialsOption`, as demonstrated by the example code loading a service account key file."],["For in-depth details on creating `google::cloud::Credentials` objects, refer to the \"Authentication Components\" section."],["The example for overriding the default authentication in the documentation is easy to follow, but you should consult the best practices for managing service accounts for more information."]]],[]]
