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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 provides documentation for various versions of the C++ client library for Bare Metal Solution, ranging from version 2.11.0 up to the release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the C++ client library for Bare Metal Solution is 2.37.0-rc, which is the most recent release candidate.\u003c/p\u003e\n"],["\u003cp\u003eThe page explains how to override the default Application Default Credentials (ADC) used by the client libraries for authentication with Google Cloud Services.\u003c/p\u003e\n"],["\u003cp\u003eOverriding default credentials can be achieved by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated in an example that loads a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eFor best practices regarding service account keys, refer to the linked guide, and for more details on creating credential objects, consult the "Authentication Components" section.\u003c/p\u003e\n"]]],[],null,[]]
