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"]],[["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 2025-03-05 UTC."],[[["This page provides documentation for overriding default authentication credentials when using Google Cloud client libraries, specifically within the context of the Dataproc service."],["The default authentication method utilizes Application Default Credentials, but users can override this by providing a `UnifiedCredentialsOption`, such as loading a service account key file."],["The documentation offers examples for several `*Client` classes, like `AutoscalingPolicyServiceClient`, `BatchControllerClient`, and others, all demonstrating how to implement service account authentication."],["The latest release candidate version for this documentation is 2.37.0-rc, and several previous versions are available, starting from 2.11.0 and extending up to 2.36.0, along with the current stable version of 2.15.1."],["Additional resources are available, including a link to the best practices guide for managing service account keys, as well as more information on the factory functions to create `google::cloud::Credentials` objects."]]],[]]