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::managedidentities_v1::ManagedIdentitiesServiceClient(
google::cloud::managedidentities_v1::
MakeManagedIdentitiesServiceConnection(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."],[[["This webpage provides documentation for overriding default authentication credentials in Google Cloud C++ client libraries for the Managed Identities service, with the latest version being 2.37.0-rc."],["The client libraries use Application Default Credentials by default, but users can override this behavior using the `UnifiedCredentialsOption`."],["A practical example demonstrates how to load a service account key file explicitly using the `MakeServiceAccountCredentials` function."],["The page includes links to additional resources, such as best practices for managing service account keys and information on authentication components for creating `google::cloud::Credentials` objects."],["The documentation covers multiple versions of the library, ranging from version 2.11.0 up to 2.37.0-rc, with each version providing documentation for overriding authentication credentials."]]],[]]
