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::osconfig_agentendpoint_v1::AgentEndpointServiceClient(
google::cloud::osconfig_agentendpoint_v1::
MakeAgentEndpointServiceConnection(options));
}
Follow these links to find examples for other *Client classes:
[[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["This page provides documentation for various versions of the OS Config C++ client library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc."],["The client libraries typically use Application Default Credentials for authentication, but users can override this by using the `UnifiedCredentialsOption`."],["The documentation includes code examples that demonstrate how to explicitly load a service account key file to override the default authentication, which can be found across different client classes."],["Users can refer to the provided links for more information on managing service account keys and using factory functions to create credentials objects, such as in the \"Best practices for managing service account keys\" and \"Authentication Components\" respectively."],["The content provides examples for overriding authentication in `AgentEndpointServiceClient`, `OsConfigServiceClient`, and `OsConfigZonalServiceClient`."]]],[]]
