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::networkmanagement_v1::ReachabilityServiceClient(
google::cloud::networkmanagement_v1::MakeReachabilityServiceConnection(
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 page lists various versions of the C++ network management library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc."],["The client libraries typically use Application Default Credentials for authentication with Google Cloud Services, but users can override this default behavior."],["Overriding default credentials can be achieved by providing a `UnifiedCredentialsOption`, such as loading a service account key file explicitly."],["The provided code example demonstrates how to override the default authentication by loading credentials from a service account key file."],["The [Authentication Components](https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html) section offers details on creating `google::cloud::Credentials` objects."]]],[]]
