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::parametermanager_v1::ParameterManagerClient(
google::cloud::parametermanager_v1::MakeParameterManagerConnection(
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 2025-08-01 UTC."],[[["Client libraries typically use Application Default Credentials for Google Cloud Services authentication, but this can be overridden."],["You can override the default credentials by providing the UnifiedCredentialsOption, such as explicitly loading a service account key file."],["The example provided demonstrates how to load a service account key file using `MakeServiceAccountCredentials`, but users should consult best practices for managing service account keys."],["The document contains two versions of API documentation: the latest release candidate 2.37.0-rc, and the previous release 2.36.0."]]],[]]
