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"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThis page provides documentation for various versions of the Storage Control client library, ranging from version 2.21.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe Storage Control client libraries typically use Application Default Credentials for authentication with Google Cloud Services, but this can be overridden when necessary.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication by utilizing \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and explicitly loading a service account key file, as shown in the provided example.\u003c/p\u003e\n"],["\u003cp\u003eFor more in-depth guidance on managing service account keys and authentication, you can refer to the "Best practices for managing service account keys" guide and the "Authentication Components" section.\u003c/p\u003e\n"]]],[],null,[]]