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::scheduler_v1::CloudSchedulerClient(
google::cloud::scheduler_v1::MakeCloudSchedulerConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThe latest release candidate version is 2.37.0-rc, and a range of previous versions are also available, from 2.36.0 down to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eClient libraries typically use Application Default Credentials for Google Cloud Services authentication, but this can be overridden if needed.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default credentials by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and explicitly loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example demonstrates how to load a service account key file to override authentication credentials, using the \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e function.\u003c/p\u003e\n"],["\u003cp\u003eRefer to the "Best practices for managing service account keys" guide and "Authentication Components" for additional details on credentials management and factory functions.\u003c/p\u003e\n"]]],[],null,[]]
