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::tpu_v1::TpuClient(
google::cloud::tpu_v1::MakeTpuConnection(options));
}
Follow these links to find examples for other *Client classes:
[[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 versioned documentation for the \u003ccode\u003etpu\u003c/code\u003e C++ client library, spanning from version 2.11.0 to the latest release candidate 2.37.0-rc, along with instructions to override authentication credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries utilize Application Default Credentials for authentication with Google Cloud Services unless otherwise specified.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication can be overridden by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, exemplified by loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe document provides links to examples for other \u003ccode\u003e*Client\u003c/code\u003e classes such as \u003ccode\u003etpu_v1::TpuClient\u003c/code\u003e and \u003ccode\u003etpu_v2::TpuClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eBest practices for managing service account keys are referenced, as is additional information about Authentication Components.\u003c/p\u003e\n"]]],[],null,[]]
