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 2025-03-05 UTC."],[[["The latest version available is 2.15.0-rc, with other versions including 2.14.0, 2.13.0, 2.12.0, and 2.11.0 also listed."],["Client libraries default to using Application Default Credentials for authenticating with Google Cloud Services, but this can be overridden."],["You can override the default authentication by using the UnifiedCredentialsOption, such as loading a service account key file explicitly."],["The example provided demonstrates loading a service account key file for authentication, but users should refer to the best practices guide for managing service account keys."],["Additional information on creating `google::cloud::Credentials` objects can be found in the Authentication Components documentation."]]],[]]
