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::essentialcontacts_v1::EssentialContactsServiceClient(
google::cloud::essentialcontacts_v1::
MakeEssentialContactsServiceConnection(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 2025-03-05 UTC."],[[["The webpage provides documentation for various versions of the C++ client library, ranging from version 2.12.0 to the latest release candidate 2.37.0-rc."],["The default authentication method for the client libraries is Application Default Credentials, but this can be overridden using the `UnifiedCredentialsOption`."],["The documentation includes an example of loading a service account key file to override the default authentication, using the `MakeServiceAccountCredentials` method."],["Users are directed to the \"Best practices for managing service account keys\" guide for more information on the best practices in authentication."],["The \"Authentication Components\" documentation is provided for further information on creating `google::cloud::Credentials` objects."]]],[]]
