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::apikeys_v2::ApiKeysClient(
google::cloud::apikeys_v2::MakeApiKeysConnection(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 2025-03-14 UTC."],[[["This webpage provides documentation for overriding default authentication credentials when using Google Cloud C++ client libraries for API keys."],["The latest version of the documentation is 2.37.0-rc, and there are links provided for previous versions ranging from 2.36.0 down to 2.11.0, as well as 2.25.1 and 2.15.1."],["By default, client libraries utilize Application Default Credentials, but users can override this by supplying a `UnifiedCredentialsOption`."],["An example demonstrates how to load a service account key file to explicitly set credentials, showing how to use `google::cloud::MakeServiceAccountCredentials` within `UnifiedCredentialsOption`."],["The documentation includes links to further reading on Authentication Components and Best Practices for managing service account keys."]]],[]]
