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::privateca_v1::CertificateAuthorityServiceClient(
google::cloud::privateca_v1::MakeCertificateAuthorityServiceConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 available version is 2.37.0-rc, with numerous other versions, including the current version 2.19.0, also listed and accessible.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries primarily use Application Default Credentials for Google Cloud Services authentication, but it is possible to override this default.\u003c/p\u003e\n"],["\u003cp\u003eOverriding default credentials can be achieved by providing the UnifiedCredentialsOption, such as loading a service account key file as shown in the provided code example.\u003c/p\u003e\n"],["\u003cp\u003eFor managing service account keys, it's recommended to refer to the "Best practices for managing service account keys" guide for comprehensive details.\u003c/p\u003e\n"],["\u003cp\u003eMore information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects is available in the "Authentication Components" documentation.\u003c/p\u003e\n"]]],[],null,[]]
