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::storagetransfer_v1::StorageTransferServiceClient(
google::cloud::storagetransfer_v1::MakeStorageTransferServiceConnection(
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 2025-04-22 UTC."],[[["The webpage provides a list of available versions for the Storage Transfer Service, ranging from the latest release candidate 2.37.0-rc down to version 2.11.0."],["By default, the client libraries utilize Application Default Credentials for Google Cloud Services authentication, but this can be overridden."],["Users can override the default authentication by using the `UnifiedCredentialsOption`, with an example provided showing how to load a service account key file."],["The webpage offers additional information on authentication components and factory functions for creating `google::cloud::Credentials` objects via a link to the Authentication Components documentation."],["The most important thing to note about overriding authentication is to follow the [Best practices for managing service account keys](https://cloud.google.com/iam/docs/best-practices-for-managing-service-account-keys) guide."]]],[]]
