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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page documents different versions of the BareMetalSolution service, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe content provides a way to override the default authentication credentials used by the client libraries, in the event that applications require something other than the Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eOverriding credentials can be achieved by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and explicitly loading a service account key file, as shown in the provided example.\u003c/p\u003e\n"],["\u003cp\u003eThe provided content highlights that, although functional, the provided example on how to override authentication credentials is basic and that the user should consult the "Best practices for managing service account keys" guide for better security.\u003c/p\u003e\n"],["\u003cp\u003eUsers can find additional information about the creation of the \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects in the "Authentication Components" documentation.\u003c/p\u003e\n"]]],[],null,[]]
