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 2025-03-21 UTC."],[[["This page provides documentation for various versions of the VPC Access service, ranging from version 2.11.0 to the latest release candidate, 2.37.0-rc."],["The client libraries default to using Application Default Credentials for authenticating with Google Cloud Services, but this can be overridden if necessary."],["You can override the default credentials by using the `UnifiedCredentialsOption`, such as by explicitly loading a service account key file."],["The provided code example demonstrates how to load a service account key file for overriding authentication credentials, but it is recommended to refer to the best practices guide for managing service account keys."],["The Authentication Components documentation offers more details on the factory functions used to create `google::cloud::Credentials` objects."]]],[]]
