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::deploy_v1::CloudDeployClient(
google::cloud::deploy_v1::MakeCloudDeployConnection(options));
}
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-07-02 UTC."],[[["This page provides documentation for overriding default authentication credentials when using Google Cloud client libraries, specifically in C++."],["The latest release candidate for these docs is version 2.37.0-rc, but there are versions available all the way back to 2.11.0."],["The client libraries use Application Default Credentials by default, but you can provide a UnifiedCredentialsOption to override this."],["An example is provided showing how to explicitly load a service account key file, which is a simple method for overriding authentication."],["The page links to further resources on authentication components and best practices for managing service account keys."]]],[]]
