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::dataproc_v1::AutoscalingPolicyServiceClient(
google::cloud::dataproc_v1::MakeAutoscalingPolicyServiceConnection(
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"]],[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 overriding default authentication credentials when using Google Cloud client libraries, specifically focusing on Dataproc services.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries typically utilize Application Default Credentials, but this can be overridden using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e for custom authentication setups.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version, as well as prior versions of the dataproc client library are documented, with the latest version being \u003ccode\u003e2.37.0-rc\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eAn example is demonstrated for explicitly loading a service account key file to override the default credentials, along with links to various Dataproc client class examples.\u003c/p\u003e\n"],["\u003cp\u003eThe user is also encouraged to review the "Best practices for managing service account keys" guide for more details, in addition to authentication component details.\u003c/p\u003e\n"]]],[],null,[]]
