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::baremetalsolution_v2::BareMetalSolutionClient(
google::cloud::baremetalsolution_v2::MakeBareMetalSolutionConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 C++ client library for Bare Metal Solution, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation explains how to override the default authentication method, which typically uses Application Default Credentials, with custom authentication credentials.\u003c/p\u003e\n"],["\u003cp\u003eUsers can utilize the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e to provide custom credentials, such as loading a service account key file as demonstrated in the example code.\u003c/p\u003e\n"],["\u003cp\u003eIt is recommended that users consult the "Best practices for managing service account keys" guide for guidance on managing service accounts.\u003c/p\u003e\n"],["\u003cp\u003eFurther information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects can be found in the Authentication Components documentation.\u003c/p\u003e\n"]]],[],null,[]]
