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::resourcesettings_v1::ResourceSettingsServiceClient(
google::cloud::resourcesettings_v1::
MakeResourceSettingsServiceConnection(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 2025-03-21 UTC."],[[["This document provides version-specific documentation for overriding authentication in the C++ client library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc."],["The client libraries use Application Default Credentials by default, but can be overridden using the `UnifiedCredentialsOption` to support different authentication needs."],["Overriding authentication is demonstrated by providing an example of loading a service account key file, via `google::cloud::UnifiedCredentialsOption` and `google::cloud::MakeServiceAccountCredentials` objects."],["For managing service account keys, it is advised to refer to the provided guide on best practices, as the example provided is simplified for understanding purposes."],["More information on factory functions to create `google::cloud::Credentials` objects can be found in the Authentication Components section."]]],[]]