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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis document provides version-specific links for overriding authentication credentials in the C++ client library, 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, but the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e can be utilized to override these defaults.\u003c/p\u003e\n"],["\u003cp\u003eOverriding default credentials can be done by explicitly loading a service account key file, as demonstrated in the example code provided.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example uses a service account key file, as a easily understandable example, but there are other practices mentioned in the documentation for managing these keys.\u003c/p\u003e\n"],["\u003cp\u003eFor further details on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, users can refer to the "Authentication Components" section.\u003c/p\u003e\n"]]],[],null,[]]
