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::container_v1::ClusterManagerClient(
google::cloud::container_v1::MakeClusterManagerConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 webpage provides documentation for various versions of a C++ library, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe content primarily focuses on how to override the default authentication credentials used by the client libraries when interacting with Google Cloud Services.\u003c/p\u003e\n"],["\u003cp\u003eUsers can override the default credentials by providing a \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, which is demonstrated with an example of loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation highlights the importance of managing service account keys securely and directs users to a guide on best practices for this.\u003c/p\u003e\n"],["\u003cp\u003eAdditional information about creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects can be found in the "Authentication Components" section of the documentation.\u003c/p\u003e\n"]]],[],null,[]]
