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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page documents how to override the default authentication credentials for Google Cloud services, which typically use Application Default Credentials (ADC).\u003c/p\u003e\n"],["\u003cp\u003eUsers can override the default credentials by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing specific credentials like a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe provided code example demonstrates how to load a service account key file to override the default authentication, using \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e and then creating options for \u003ccode\u003eTpuClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eLinks to \u003ccode\u003etpu_v1::TpuClient\u003c/code\u003e and \u003ccode\u003etpu_v2::TpuClient\u003c/code\u003e examples are provided for implementing the override with other \u003ccode\u003e*Client\u003c/code\u003e classes.\u003c/p\u003e\n"],["\u003cp\u003eThere is a range of available versions of the \u003ccode\u003eTpuClient\u003c/code\u003e, spanning from version 2.11.0 all the way to the most recent release candidate 2.37.0-rc, as well as a link to the full list of Authentication Components.\u003c/p\u003e\n"]]],[],null,[]]
