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::support_v2::CaseAttachmentServiceClient(
google::cloud::support_v2::MakeCaseAttachmentServiceConnection(
options));
}
Follow these links to find examples for other *Client classes:
[[["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."],[[["This page provides documentation for overriding default authentication credentials in Google Cloud C++ client libraries."],["The latest release candidate version is 2.37.0-rc, and multiple previous versions are also documented and available from 2.27.0 to 2.36.0, and then sporadically down to version 2.11.0."],["Client libraries typically use Application Default Credentials, but you can override this by providing the UnifiedCredentialsOption, and service account key file loading is provided as an example."],["Specific examples for overriding credentials are provided for `support_v2::CaseAttachmentServiceClient`, `support_v2::CaseServiceClient`, and `support_v2::CommentServiceClient` classes."],["For details on managing service account keys, and creating Credentials objects, consult the provided links to the best practices guide and Authentication Components."]]],[]]