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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis document provides a version history, including the latest release candidate \u003ccode\u003e2.37.0-rc\u003c/code\u003e and ranging down to version \u003ccode\u003e2.11.0\u003c/code\u003e, for the C++ container library.\u003c/p\u003e\n"],["\u003cp\u003eThe default authentication method for client libraries is Application Default Credentials, which can be overridden using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e when necessary.\u003c/p\u003e\n"],["\u003cp\u003eOverriding the default authentication can be achieved by loading a service account key file, as demonstrated in the provided example using the \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e function.\u003c/p\u003e\n"],["\u003cp\u003eFor best practices on service account key management, users should refer to the linked guide, and for more details on \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e object creation, check the "Authentication Components" page.\u003c/p\u003e\n"]]],[],null,[]]
