Unless otherwise configured, the client libraries useApplication Default Credentialsto 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 theUnifiedCredentialsOptionThe 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 2025-09-04 UTC."],[[["\u003cp\u003eThis page documents the C++ client library versions for the Recommender service, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries typically use Application Default Credentials for authentication with Google Cloud Services, but this can be overridden if necessary.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing a service account key file, as shown in the provided code example.\u003c/p\u003e\n"],["\u003cp\u003eThe example demonstrates loading a service account key file and setting it as an option for the \u003ccode\u003eRecommenderClient\u003c/code\u003e, which is an easy-to-understand method, but the provided link to the "Best practices" should be reviewed.\u003c/p\u003e\n"],["\u003cp\u003eFurther details on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects can be found in the "Authentication Components" documentation.\u003c/p\u003e\n"]]],[],null,[]]
