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 `vpcaccess` library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc."],["The default authentication method for the client libraries is Application Default Credentials, but it can be overridden when necessary."],["You can override the default authentication by utilizing the `UnifiedCredentialsOption` and providing the service account key file contents via `MakeServiceAccountCredentials`."],["The provided code example demonstrates how to load a service account key file explicitly for authentication."],["For more information on creating `google::cloud::Credentials` objects, refer to the Authentication Components documentation."]]],[]]
