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::contentwarehouse_v1::DocumentServiceClient(
google::cloud::contentwarehouse_v1::MakeDocumentServiceConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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."],[[["\u003cp\u003eThe latest version available is 2.37.0-rc, with numerous other versions, down to 2.12.0, also listed for reference.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries utilize Application Default Credentials for authenticating with Google Cloud Services, but this can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication can be customized using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated with an example showing how to load a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples for how to use service accounts with various \u003ccode\u003e*Client\u003c/code\u003e classes such as \u003ccode\u003econtentwarehouse_v1::DocumentServiceClient\u003c/code\u003e, and \u003ccode\u003econtentwarehouse_v1::DocumentLinkServiceClient\u003c/code\u003e can be found in the provided links.\u003c/p\u003e\n"],["\u003cp\u003eFor best practices regarding managing service account keys, users are referred to the Google Cloud guide on the topic and are provided with a link.\u003c/p\u003e\n"]]],[],null,[]]
