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::datastore_admin_v1::DatastoreAdminClient(
google::cloud::datastore_admin_v1::MakeDatastoreAdminConnection(
options));
}
Follow these links to find examples for other *Client classes:
[[["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 2025-03-05 UTC."],[[["This page provides documentation for overriding default authentication credentials when using Google Cloud C++ client libraries."],["The latest release candidate version is 2.37.0-rc, with a list of all other available versions going back to 2.15.1, all with examples of overriding authentication."],["Authentication is usually handled by Application Default Credentials, but you can use `UnifiedCredentialsOption` to set specific credentials, like those from a service account key file."],["Examples are provided for `datastore_admin_v1::DatastoreAdminClient` and `datastore_v1::DatastoreClient`, demonstrating how to load service account key files, which are easy to understand."],["Best practices for managing service account keys and more details on authentication are available via linked documentation, which include details on `google::cloud::Credentials` objects."]]],[]]
