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::recommender_v1::RecommenderClient(
google::cloud::recommender_v1::MakeRecommenderConnection(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 2025-04-23 UTC."],[[["This webpage provides documentation for various versions of the C++ Recommender client library, ranging from version 2.11.0 to the latest release candidate 2.37.0-rc."],["The documentation explains how to override the default authentication credentials, which usually rely on Application Default Credentials, by using `UnifiedCredentialsOption`."],["An example is provided to show users how to load a service account key file to authenticate and use the C++ client library."],["Best practices for managing service account keys can be found in the guide provided, which should be consulted for more complex uses."],["The Authentication components documentation is also provided for users who want more information on how to create `google::cloud::Credentials` objects."]]],[]]
