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::metastore_v1::DataprocMetastoreClient(
google::cloud::metastore_v1::MakeDataprocMetastoreConnection(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 2025-04-17 UTC."],[[["This document provides versioned documentation for overriding authentication credentials when using Google Cloud C++ client libraries, covering versions from 2.13.0 up to 2.37.0-rc."],["The C++ client libraries default to using Application Default Credentials, but you can override this by using the `UnifiedCredentialsOption`."],["An example is provided that demonstrates loading a service account key file to override the default credentials, and how to create an options instance."],["Examples for other client classes like `metastore_v1::DataprocMetastoreClient` and `metastore_v1::DataprocMetastoreFederationClient` are provided with links to their documentation."],["The user should review the best practices guide for managing service account keys and the Authentication Components documentation to better understand credentials."]]],[]]
