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 authentication credentials when using Google Cloud client libraries, specifically for API keys."],["The latest version of the documentation is 2.37.0-rc, and there are numerous older versions available, starting from 2.11.0 up to the latest."],["Client libraries generally utilize Application Default Credentials for authentication, but the process for overriding these defaults, by using UnifiedCredentialsOption, is described herein."],["An example is provided that demonstrates how to load a service account key file for authentication."],["The page also recommends readers to consult the documentation for [Authentication Components](https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html) and the [Best practices for managing service account keys](https://cloud.google.com/iam/docs/best-practices-for-managing-service-account-keys)."]]],[]]
