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::backupdr_v1::BackupDRClient(
google::cloud::backupdr_v1::MakeBackupDRConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 document provides guidance on overriding default authentication credentials when interacting with Google Cloud Services, which are typically managed using Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eUsers can override default credentials by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, exemplified by explicitly loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe example demonstrates setting custom authentication options using \u003ccode\u003egoogle::cloud::UnifiedCredentialsOption\u003c/code\u003e and \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e to authenticate.\u003c/p\u003e\n"],["\u003cp\u003eThere are multiple client library versions available, ranging from 2.23.0 to 2.37.0-rc, each offering a documentation link to the \u003ccode\u003e/backupdr-override-authentication\u003c/code\u003e reference page.\u003c/p\u003e\n"],["\u003cp\u003eAdditional information on managing service account keys and creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects is available in the linked guides and documentation.\u003c/p\u003e\n"]]],[],null,[]]
