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 2025-03-14 UTC."],[[["This webpage provides documentation for overriding authentication credentials when using Google Cloud client libraries, specifically for Data Migration Service."],["The latest version available is 2.37.0-rc, and the page contains links to versions ranging from 2.11.0 to 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 provided code example demonstrates how to explicitly load a service account key file to override default credentials using `UnifiedCredentialsOption`."],["For further information on creating Credentials objects and best practices for managing service account keys, consult the linked \"Authentication Components\" and the \"Best practices for managing service account keys\" documentation, respectively."]]],[]]
