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::ids_v1::IDSClient(
google::cloud::ids_v1::MakeIDSConnection(options));
}
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThe webpage provides documentation for various versions of a C++ library, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe content primarily focuses on how to override the default authentication credentials used by the client libraries when interacting with Google Cloud Services.\u003c/p\u003e\n"],["\u003cp\u003eOverriding authentication can be achieved by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing the necessary credentials, such as loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe provided code example demonstrates the process of explicitly loading a service account key file to override default credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation also links to additional resources, including best practices for managing service account keys and more details on authentication components, such as \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,[]]
