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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page provides documentation for overriding authentication credentials when using Google Cloud client libraries, specifically focusing on the \u003ccode\u003eservicemanagement\u003c/code\u003e service.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version available is 2.37.0-rc, and a range of other versions, from 2.36.0 down to 2.11.0, are also documented and accessible.\u003c/p\u003e\n"],["\u003cp\u003eThe default method of authentication for client libraries is Application Default Credentials, but you can override this using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eAn example is provided to show how to load authentication from a service account key file, using \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e and setting it in the \u003ccode\u003eOptions\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eMore information about creating \u003ccode\u003eCredentials\u003c/code\u003e objects and authentication can be found in the Authentication Components section of the documentation.\u003c/p\u003e\n"]]],[],null,[]]
