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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis page provides documentation for various versions of the C++ client library, ranging from version 2.11.0 to the latest release candidate 2.37.0-rc, with each version linked to its corresponding documentation.\u003c/p\u003e\n"],["\u003cp\u003eThe default authentication for Google Cloud Services uses Application Default Credentials, but users can override this behavior.\u003c/p\u003e\n"],["\u003cp\u003eTo override default credentials, you can provide the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e by specifying a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation provides an example of how to explicitly load a service account key file using \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects and best practices for managing service account keys, users can consult the linked documentation.\u003c/p\u003e\n"]]],[],null,[]]
