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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 details how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services, specifically within the context of C++ client libraries for Pub/Sub Lite.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the Pub/Sub Lite C++ client library is 2.37.0-rc, and the content includes documentation for versions spanning from 2.11.0 up to the latest release candidate.\u003c/p\u003e\n"],["\u003cp\u003eUsers can override default credentials by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing a service account key file, as shown in the example code snippet that loads a service account key from a file.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation provides example links for overriding authentication credentials within the \u003ccode\u003epubsublite::AdminServiceClient\u003c/code\u003e and \u003ccode\u003epubsublite::TopicStatsServiceClient\u003c/code\u003e classes.\u003c/p\u003e\n"],["\u003cp\u003eFor best security practices when using service account keys, users are advised to consult the linked "Best practices for managing service account keys" guide, also authentication component are linked for further information.\u003c/p\u003e\n"]]],[],null,[]]
