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::translate_v3::TranslationServiceClient(
google::cloud::translate_v3::MakeTranslationServiceConnection(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 webpage provides documentation for different versions of the C++ client library, ranging from version 2.11.0 up to the release candidate 2.37.0-rc, with each version linked to its corresponding documentation."],["The client libraries, by default, use Application Default Credentials for authentication with Google Cloud Services."],["You can override the default authentication by utilizing the UnifiedCredentialsOption, as demonstrated in the provided C++ example which uses a service account key file."],["For more detailed information on managing service account keys, you can refer to the \"Best practices for managing service account keys\" guide."],["For more information on the factory functions to create Credentials objects, refer to the \"Authentication Components\" documentation."]]],[]]
