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::retail_v2::CatalogServiceClient(
google::cloud::retail_v2::MakeCatalogServiceConnection(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 2025-03-21 UTC."],[[["This page details how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services, which is done by providing a `UnifiedCredentialsOption`."],["The content provides a list of Retail C++ library versions, starting from version 2.11.0 up to the latest release candidate, 2.37.0-rc, each linked to their respective override authentication documentation."],["An example demonstrates explicitly loading a service account key file to override default credentials, showcasing how to set up `UnifiedCredentialsOption` using `MakeServiceAccountCredentials`."],["Links are provided to examples for several `*Client` classes within the `retail_v2` namespace, such as `CatalogServiceClient`, `CompletionServiceClient`, and others, for service account usage."],["The document recommends consulting the \"Best practices for managing service account keys\" guide and provides a link to \"Authentication Components\" for more in-depth information on creating `google::cloud::Credentials` objects."]]],[]]