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::servicemanagement_v1::ServiceManagerClient(
google::cloud::servicemanagement_v1::MakeServiceManagerConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 webpage provides documentation for various versions of the Service Management API, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation details how to override default authentication credentials using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e within the client libraries.\u003c/p\u003e\n"],["\u003cp\u003eA code example demonstrates explicitly loading a service account key file for authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe document advises consulting the "Best practices for managing service account keys" guide for further details on managing service account keys.\u003c/p\u003e\n"],["\u003cp\u003eAdditional information on factory functions for creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects can be found in the "Authentication Components" section.\u003c/p\u003e\n"]]],[],null,[]]
