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::advisorynotifications_v1::
AdvisoryNotificationsServiceClient(
google::cloud::advisorynotifications_v1::
MakeAdvisoryNotificationsServiceConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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, ranging from version 2.11.0 up to the release candidate 2.37.0-rc, with links to documentation on each specific version.\u003c/p\u003e\n"],["\u003cp\u003eThe content explains how to override the default Application Default Credentials (ADC) for Google Cloud service authentication using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e in cases where custom credentials are required.\u003c/p\u003e\n"],["\u003cp\u003eAn example demonstrates how to explicitly load a service account key file for authentication, highlighting the use of \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation directs the user to the "Best practices for managing service account keys" guide for additional information on handling service account credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe page also contains links to documentation about "Authentication Components" where you can find more information regarding the factory functions to create \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,[]]
