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::vpcaccess_v1::VpcAccessServiceClient(
google::cloud::vpcaccess_v1::MakeVpcAccessServiceConnection(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."],[[["The webpage provides documentation for various versions of the C++ client library, ranging from version 2.11.0 up to the release candidate 2.37.0-rc, with links to documentation on VPC Access authentication overrides for each version."],["By default, the C++ client libraries use Application Default Credentials (ADC) for authenticating with Google Cloud Services, but you may need to override this in certain cases."],["Authentication can be overridden using the `UnifiedCredentialsOption`, such as by explicitly loading a service account key file, demonstrated with a code snippet example."],["For in-depth details on creating `google::cloud::Credentials` objects, refer to the Authentication Components section of the documentation."],["Best practices for managing service account keys are explained on the provided link."]]],[]]
