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::serviceusage_v1::ServiceUsageClient(
google::cloud::serviceusage_v1::MakeServiceUsageConnection(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 outlines the available versions of the service usage documentation, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc."],["The client libraries default to using Application Default Credentials for authentication with Google Cloud Services, but can be overridden."],["Users can override the default authentication by providing a UnifiedCredentialsOption, such as explicitly loading a service account key file."],["The example shows how to load a service account key file using `google::cloud::UnifiedCredentialsOption` and `google::cloud::MakeServiceAccountCredentials`."],["For detailed information about creating `google::cloud::Credentials` objects, refer to the Authentication Components section in the documentation."]]],[]]