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::datamigration_v1::DataMigrationServiceClient(
google::cloud::datamigration_v1::MakeDataMigrationServiceConnection(
options));
}
[[["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 a comprehensive list of versioned documentation for overriding authentication in the C++ Data Migration library, starting from version 2.11.0 and going up to the latest release candidate 2.37.0-rc."],["The default authentication method for client libraries is Application Default Credentials, but users can override this by using the `UnifiedCredentialsOption`."],["The example provided demonstrates how to override the default credentials by loading a service account key file, which offers a straightforward method for understanding the override process."],["Users are directed to the \"Best practices for managing service account keys\" guide for detailed information and recommendations on key management."],["Further information on creating `google::cloud::Credentials` objects can be found in the \"Authentication Components\" section of the C++ documentation."]]],[]]