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 webpage provides documentation for overriding default authentication credentials when using Google Cloud client libraries, specifically focusing on the `UnifiedCredentialsOption`."],["The latest version available is 2.37.0-rc, and the content includes a list of documentation for versions ranging from 2.11.0 up to 2.37.0-rc."],["The provided example code demonstrates how to explicitly load a service account key file to override the default authentication, using `UnifiedCredentialsOption` and `MakeServiceAccountCredentials`."],["The documentation emphasizes the importance of consulting the \"Best practices for managing service account keys\" guide for more secure and detailed information."],["The page also includes a \"See Also\" section linking to \"Authentication Components\" for additional details on creating `google::cloud::Credentials` objects."]]],[]]