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::tasks_v2::CloudTasksClient(
google::cloud::tasks_v2::MakeCloudTasksConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 version available is 2.37.0-rc, with numerous other versions, down to 2.11.0, also listed.\u003c/p\u003e\n"],["\u003cp\u003eClient libraries typically use Application Default Credentials (ADC) for Google Cloud Service authentication, but this can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default credentials by providing the UnifiedCredentialsOption, as demonstrated with a service account key file example.\u003c/p\u003e\n"],["\u003cp\u003eThe provided code example demonstrates how to explicitly load credentials from a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on managing service account keys and creating Credentials objects, refer to the linked documentation on best practices and authentication components.\u003c/p\u003e\n"]]],[],null,[]]
