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 2025-03-14 UTC."],[[["This page provides documentation for various versions of the Text-to-Speech C++ client library, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc."],["The client libraries typically use Application Default Credentials for authentication, but this can be overridden using the UnifiedCredentialsOption."],["You can override the default credentials by loading a service account key file, as demonstrated in the provided code example that utilizes the `UnifiedCredentialsOption` and `MakeServiceAccountCredentials`."],["The document advises users to consult the \"Best practices for managing service account keys\" guide for detailed information on key management."],["The \"Authentication Components\" link offers additional details on factory functions for creating `google::cloud::Credentials` objects."]]],[]]