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::pubsublite::AdminServiceClient(
google::cloud::pubsublite::MakeAdminServiceConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 provides documentation for various versions of the C++ Pub/Sub Lite client library, ranging from version 2.11.0 to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries typically use Application Default Credentials for Google Cloud authentication, but you can override this with the UnifiedCredentialsOption.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example demonstrates how to override default authentication by loading a service account key file, and there are further example links provided for \u003ccode\u003epubsublite::AdminServiceClient\u003c/code\u003e and \u003ccode\u003epubsublite::TopicStatsServiceClient\u003c/code\u003e classes.\u003c/p\u003e\n"],["\u003cp\u003eUsers are encouraged to review the "Best practices for managing service account keys" guide for more in-depth details on service account keys, as this is an easy to understand example.\u003c/p\u003e\n"],["\u003cp\u003eThe page also directs users to the "Authentication Components" section for more information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,[]]
