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 2025-03-05 UTC."],[[["This document details how to override the default authentication credentials used by client libraries when interacting with Google Cloud Services."],["The latest version of the documentation is 2.37.0-rc, and previous versions, dating back to 2.25.1, are also available for reference."],["By providing a `UnifiedCredentialsOption`, users can override the default [Application Default Credentials](https://cloud.google.com/docs/authentication#adc)."],["The example shows how to load authentication credentials from a service account key file."],["Users can use the [Authentication Components](https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html) section for more information on creating `google::cloud::Credentials` objects."]]],[]]