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::gkebackup_v1::BackupForGKEClient(
google::cloud::gkebackup_v1::MakeBackupForGKEConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThe latest version available is 2.37.0-rc, with numerous other versions, such as 2.36.0, 2.35.0, and so on, also listed, going down to version 2.12.0.\u003c/p\u003e\n"],["\u003cp\u003eClient libraries typically use Application Default Credentials (ADC) for authenticating with Google Cloud Services, but this default can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication by using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated by the example showing how to explicitly load a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example shows the minimum error handling and is easy to understand, but the user is encouraged to look at best practices for managing service accounts keys.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, users can refer to the Authentication Components documentation.\u003c/p\u003e\n"]]],[],null,[]]
