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::networksecurity_v1::NetworkSecurityClient(
google::cloud::networksecurity_v1::MakeNetworkSecurityConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 latest version available is 2.37.0-rc, with various prior versions listed, going back to 2.13.0.\u003c/p\u003e\n"],["\u003cp\u003eClient libraries typically use Application Default Credentials for Google Cloud service authentication, but this can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eYou can override default authentication by utilizing \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated by loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example demonstrates overriding the default authentication, however it's recommended to refer to the "Best practices for managing service account keys" for optimal practices.\u003c/p\u003e\n"],["\u003cp\u003eThe Authentication Components section provides extra information on the factory functions to make \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,[]]
