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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-07-09 UTC."],[[["This page provides documentation for various versions of the C++ client library for Google Cloud's Private Certificate Authority service, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc."],["The client libraries default to using Application Default Credentials (ADC) for authentication, which is suitable for most applications."],["You can override the default authentication by using the `UnifiedCredentialsOption`, enabling the use of service account key files or other credential types."],["The provided code example demonstrates how to load credentials from a service account key file using `google::cloud::UnifiedCredentialsOption` and `google::cloud::MakeServiceAccountCredentials`."],["Users should consult the \"Best practices for managing service account keys\" guide for secure service account key management, and the \"Authentication Components\" section for more details on creating `google::cloud::Credentials` objects."]]],[]]
