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::servicemanagement_v1::ServiceManagerClient(
google::cloud::servicemanagement_v1::MakeServiceManagerConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 webpage provides documentation for overriding authentication credentials when using Google Cloud client libraries, specifically for \u003ccode\u003eservicemanagement-override-authentication\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version for this documentation is 2.37.0-rc, while version 2.29.0 is currently in use.\u003c/p\u003e\n"],["\u003cp\u003eThe default method of authentication is via Application Default Credentials, however users may use \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e to override authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe provided code example shows how to explicitly load a service account key file to override the default credentials.\u003c/p\u003e\n"],["\u003cp\u003eUsers can consult the "Best practices for managing service account keys" and "Authentication Components" links for more information.\u003c/p\u003e\n"]]],[],null,[]]
