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::texttospeech_v1::TextToSpeechClient(
google::cloud::texttospeech_v1::MakeTextToSpeechConnection(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 2025-05-07 UTC."],[[["The latest version available is 2.37.0-rc, with numerous previous versions of the TextToSpeech client library also listed, ranging down to version 2.11.0."],["The TextToSpeech client library typically uses Application Default Credentials for authentication, but users can override this default behavior."],["Authentication can be overridden by providing the UnifiedCredentialsOption, as shown in the example where a service account key file is explicitly loaded."],["For security and best practices regarding service account key management, the provided guide is advised to be consulted."],["Further information on creating `google::cloud::Credentials` objects can be found in the Authentication Components documentation."]]],[]]
