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::channel_v1::CloudChannelServiceClient(
google::cloud::channel_v1::MakeCloudChannelServiceConnection(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"]],[["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 2025-03-14 UTC."],[[["This page provides documentation for overriding default authentication credentials when using Google Cloud client libraries, specifically focusing on the `UnifiedCredentialsOption`."],["The latest version available is 2.37.0-rc, with documentation also available for a range of previous versions, from 2.36.0 down to 2.11.0."],["The documentation uses the `channel_v1::CloudChannelServiceClient` as an example to demonstrate how to explicitly load a service account key file."],["The page links to further information on best practices for managing service account keys and authentication components, along with examples of other `*Client` classes."],["Client libraries typically utilize Application Default Credentials unless otherwise specified by using `UnifiedCredentialsOption` to load a service account file."]]],[]]
