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 provides documentation for overriding default authentication credentials in the C++ client libraries for Google Cloud Services, covering versions from 2.11.0 up to the latest release candidate 2.37.0-rc."],["The default authentication method uses Application Default Credentials, but can be overridden using `UnifiedCredentialsOption` to manage authentication manually."],["An example demonstrates loading authentication from a service account key file, which can be further configured to include more advanced options."],["Refer to the \"Best practices for managing service account keys\" guide and the \"Authentication Components\" section for a comprehensive understanding of secure credential management."],["This page provides links to the different versions of documentation for the networkmanagement override authentication feature, ranging from version 2.11.0 all the way up to 2.37.0-rc."]]],[]]