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 provides documentation for various versions of the C++ client library, ranging from version 2.11.0 up to the release candidate 2.37.0-rc, with each version linked to its corresponding documentation on overriding authentication."],["The documentation explains how to override the default authentication credentials used by the C++ client libraries, which typically rely on Application Default Credentials."],["You can override the default credentials by utilizing the `UnifiedCredentialsOption` and providing the necessary credentials, such as loading a service account key file, as demonstrated in the provided example code."],["The page refers to the \"Best practices for managing service account keys\" guide for additional information on handling service account keys securely, as well as to the \"Authentication Components\" for more information on factory functions."]]],[]]
