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::functions_v1::CloudFunctionsServiceClient(
google::cloud::functions_v1::MakeCloudFunctionsServiceConnection(
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."],[[["This page details how to override default authentication credentials for Google Cloud Services using the `UnifiedCredentialsOption` in the C++ client library."],["The most recent version documented is 2.37.0-rc, with a history of versions available down to 2.11.0, each with corresponding documentation for `functions-override-authentication`."],["Application Default Credentials (ADC) are used by default, but you can supply a service account key file to override this behavior, as shown in the code example."],["For advanced usage, the page links to documentation on best practices for managing service account keys and the `Authentication Components` for creating `google::cloud::Credentials` objects."],["The example shows how to load a service account key file using an input file stream, which then can be used to create a `CloudFunctionsServiceClient`."]]],[]]
