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 latest version available is 2.37.0-rc, with multiple previous versions available ranging from 2.36.0 down to 2.11.0."],["Client libraries default to using Application Default Credentials for authentication with Google Cloud Services, but this can be overridden."],["To override the default authentication, you can use the UnifiedCredentialsOption and explicitly load a service account key file, as shown in the provided code example."],["For detailed information on managing service account keys, refer to the \"Best practices for managing service account keys\" guide."],["The Authentication Components documentation provides more information on creating `google::cloud::Credentials` objects using factory functions."]]],[]]
