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::cloudbuild_v1::CloudBuildClient(
google::cloud::cloudbuild_v1::MakeCloudBuildConnection(options));
}
Follow these links to find examples for other *Client classes:
[[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 details how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services, using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version available is \u003ccode\u003e2.37.0-rc\u003c/code\u003e, and there is a list of previous versions including \u003ccode\u003e2.15.1\u003c/code\u003e all the way to \u003ccode\u003e2.36.0\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eA service account key file can be explicitly loaded to override default credentials, as demonstrated in the provided code example.\u003c/p\u003e\n"],["\u003cp\u003eExamples for \u003ccode\u003ecloudbuild_v1::CloudBuildClient\u003c/code\u003e and \u003ccode\u003ecloudbuild_v2::RepositoryManagerClient\u003c/code\u003e are provided to show how to override the credentials for those services.\u003c/p\u003e\n"],["\u003cp\u003eFor managing service account keys and further information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, it is advised to consult the provided links to the best practices and authentication components respectively.\u003c/p\u003e\n"]]],[],null,[]]
