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::alloydb_v1::AlloyDBAdminClient(
google::cloud::alloydb_v1::MakeAlloyDBAdminConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 webpage provides documentation for various versions of the AlloyDB C++ client library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe default authentication method for the client libraries is Application Default Credentials, which can be overridden when necessary.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default credentials by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and, for example, loading a service account key file explicitly, which is shown in the provided code snippet.\u003c/p\u003e\n"],["\u003cp\u003eThe example demonstrates using a service account key file to authenticate, with a recommendation to review the best practices guide for service account key management.\u003c/p\u003e\n"],["\u003cp\u003eThe page links to additional information on Authentication Components to learn more about the functions available to create google::cloud::Credentials objects.\u003c/p\u003e\n"]]],[],null,[]]