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::batch_v1::BatchServiceClient(
google::cloud::batch_v1::MakeBatchServiceConnection(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 2025-03-05 UTC."],[[["This document provides versioned documentation for overriding authentication credentials when using the C++ client libraries with Google Cloud Services."],["The latest version available is 2.37.0-rc, and the list contains documentation links for versions back to 2.11.0."],["By default, client libraries authenticate with Google Cloud Services using Application Default Credentials, but these defaults can be overridden."],["Authentication can be overridden by providing a `UnifiedCredentialsOption`, such as explicitly loading a service account key file."],["The provided example code shows how to override authentication by loading a service account key file, but users are encouraged to refer to the best practices guide for managing service account keys for more detailed guidance."]]],[]]