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::config_v1::ConfigClient(
google::cloud::config_v1::MakeConfigConnection(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 2025-03-05 UTC."],[[["The latest version of the configuration documentation is 2.37.0-rc, with other listed versions ranging from 2.16.0 up to 2.36.0."],["Client libraries typically use Application Default Credentials for authentication, but these can be overridden for specific use cases."],["Authentication can be overridden by providing the UnifiedCredentialsOption, such as explicitly loading a service account key file."],["A detailed guide, titled 'Best practices for managing service account keys', is provided for more in-depth information on the overriding of credentials."],["The Authentication Components section provides additional details on factory functions for creating `google::cloud::Credentials` objects."]]],[]]
