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::speech_v1::AdaptationClient(
google::cloud::speech_v1::MakeAdaptationConnection(options));
}
Follow these links to find examples for other *Client classes:
[[["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 provides version-specific details for overriding default authentication credentials when using Google Cloud Speech client libraries in C++."],["The latest version available is 2.37.0-rc, and the documentation includes details from version 2.36.0 down to 2.11.0."],["Client libraries typically use Application Default Credentials, but the provided code snippet and instructions illustrate how to override this by loading a service account key file with the UnifiedCredentialsOption."],["Examples are provided for `speech_v1::AdaptationClient`, `speech_v1::SpeechClient`, and `speech_v2::SpeechClient` to show how to manage service accounts."],["There are also further links available to explain the [Authentication Components](https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html) and the [Best practices for managing service account keys](https://cloud.google.com/iam/docs/best-practices-for-managing-service-account-keys)."]]],[]]
