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 page lists various versions of the `managedidentities-override-authentication` documentation, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc."],["The default authentication method for client libraries is Application Default Credentials, but this can be overridden when required for certain applications."],["You can override the default credentials by providing the `UnifiedCredentialsOption`, as shown in the example which uses a service account key file."],["The provided code example demonstrates loading a service account key file and using it for authentication by setting the `UnifiedCredentialsOption`."],["The \"See Also\" section provides a link to Authentication Components, which offers further details about the factory functions that create `google::cloud::Credentials` objects."]]],[]]
