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."],[[["The webpage provides documentation for overriding default authentication credentials when using Google Cloud C++ client libraries, specifically referencing `ManagedIdentitiesServiceClient`."],["The latest release candidate version for the library is 2.37.0-rc, while version 2.18.0 is displayed on the page, and multiple versions between 2.11.0 and 2.37.0-rc are also documented."],["Application Default Credentials are the standard method of authentication with Google Cloud Services, but can be overridden."],["Overriding authentication can be done by using `UnifiedCredentialsOption`, as demonstrated with an example of loading a service account key file."],["Users are advised to follow best practices for managing service account keys, and can refer to the Authentication Components section for more information."]]],[]]