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::cloudquotas_v1::CloudQuotasClient(
google::cloud::cloudquotas_v1::MakeCloudQuotasConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 Cloud Quotas C++ client library, ranging from version 2.20.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation outlines how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eUsers can override default credentials by explicitly loading a service account key file, as demonstrated in the example code provided.\u003c/p\u003e\n"],["\u003cp\u003eThe example code shows how to set the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e using the \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e function in order to load the credentials.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects and general best practices for managing service account keys, refer to the "Authentication Components" and the "Best practices for managing service account keys" documentation pages, respectively.\u003c/p\u003e\n"]]],[],null,[]]
