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::storagecontrol_v2::StorageControlClient(
google::cloud::storagecontrol_v2::MakeStorageControlConnection(
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 2025-03-21 UTC."],[[["This page details how to override the default authentication credentials used by client libraries when interacting with Google Cloud Services."],["The default authentication mechanism utilizes Application Default Credentials, but alternative methods are provided for specific use cases."],["You can override the default credentials by using the `UnifiedCredentialsOption`, as demonstrated with an example of loading a service account key file."],["The page lists the different versions of the library, from 2.21.0 up to 2.37.0-rc, and it provides a link to the reference for each version."],["For more information on creating `google::cloud::Credentials` objects, refer to the Authentication Components documentation."]]],[]]
