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::publicca_v1::PublicCertificateAuthorityServiceClient(
google::cloud::publicca_v1::
MakePublicCertificateAuthorityServiceConnection(options));
}
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-03-21 UTC."],[[["The latest version of the documentation is 2.37.0-rc, with a link to its specific page regarding overriding authentication credentials."],["This page documents how to override the default authentication credentials, known as Application Default Credentials, used by client libraries when interacting with Google Cloud Services."],["Overriding the default authentication is achieved by utilizing the `UnifiedCredentialsOption`, and a practical example is given to demonstrate how to load a service account key file to override it."],["The best practices for managing service account keys are highly recommended, providing an additional link for more details."],["Further information on creating `google::cloud::Credentials` objects can be found in the Authentication Components section."]]],[]]
