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::batch_v1::BatchServiceClient(
google::cloud::batch_v1::MakeBatchServiceConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 a version history, detailing releases from version 2.11.0 up to the latest release candidate, 2.37.0-rc, all related to batch override authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries use Application Default Credentials for authentication with Google Cloud Services unless overridden.\u003c/p\u003e\n"],["\u003cp\u003eYou can override default credentials by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, for instance, loading a service account key file explicitly.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example code shows a basic method to load a service account key file and create a \u003ccode\u003eBatchServiceClient\u003c/code\u003e with specific authentication options.\u003c/p\u003e\n"],["\u003cp\u003eFor more on managing service account keys, refer to the "Best practices for managing service account keys" guide and the "Authentication Components" documentation for details on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,[]]
