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::iot_v1::DeviceManagerClient(
google::cloud::iot_v1::MakeDeviceManagerConnection(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."],[[["The client libraries typically use Application Default Credentials for Google Cloud Services authentication, but this default can be overridden."],["You can override default credentials by providing a `UnifiedCredentialsOption`, which allows for custom authentication methods."],["An example is provided demonstrating how to explicitly load a service account key file for authentication."],["The provided code example is simplified for clarity, and it is recommended to review best practices for managing service account keys."],["Further details on creating `google::cloud::Credentials` objects can be found in the Authentication Components documentation."]]],[]]
