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 documents various versions of the C++ client library, specifically related to overriding authentication, with the latest version being 2.37.0-rc."],["The library versions range from 2.11.0 up to the latest release candidate, 2.37.0-rc, and provide documentation on how to override default authentication credentials."],["Overriding default authentication is achieved by providing the `UnifiedCredentialsOption`, allowing you to load a service account key file explicitly."],["Examples are available for `support_v2::CaseAttachmentServiceClient`, `support_v2::CaseServiceClient`, and `support_v2::CommentServiceClient`, demonstrating how to use service account keys with different client classes."],["Default authentication typically uses Application Default Credentials, and more information about authentication components, including factory functions for creating `google::cloud::Credentials` objects, can be found in the Authentication Components section."]]],[]]