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::resourcemanager_v3::FoldersClient(
google::cloud::resourcemanager_v3::MakeFoldersConnection(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"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThis page details how to override the default authentication credentials used by Google Cloud client libraries, which typically rely on Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eTo override the default credentials, the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e can be used to specify a service account key file or other credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the resource manager documentation is version \u003ccode\u003e2.37.0-rc\u003c/code\u003e, and the page also contains information about past versions ranging from \u003ccode\u003e2.36.0\u003c/code\u003e down to \u003ccode\u003e2.11.0\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eExamples of overriding authentication are provided for various \u003ccode\u003eClient\u003c/code\u003e classes, including \u003ccode\u003eFoldersClient\u003c/code\u003e, \u003ccode\u003eOrganizationsClient\u003c/code\u003e, \u003ccode\u003eProjectsClient\u003c/code\u003e, and more, all under the \u003ccode\u003eresourcemanager_v3\u003c/code\u003e namespace.\u003c/p\u003e\n"],["\u003cp\u003eFor managing service account keys effectively, the Best practices guide is linked and authentication components are also linked for further exploration.\u003c/p\u003e\n"]]],[],null,[]]
