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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 from 2.36.0 down to 2.12.0 also being accessible.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries authenticate using Application Default Credentials, but you can override this for specific scenarios.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication credentials can be overridden by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples of overriding authentication with a service account key file are provided for multiple \u003ccode\u003e*Client\u003c/code\u003e classes including \u003ccode\u003eDocumentServiceClient\u003c/code\u003e, \u003ccode\u003eDocumentLinkServiceClient\u003c/code\u003e, \u003ccode\u003eDocumentSchemaServiceClient\u003c/code\u003e, \u003ccode\u003eRuleSetServiceClient\u003c/code\u003e, and \u003ccode\u003eSynonymSetServiceClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eIt is recommended to consult the "Best practices for managing service account keys" guide for more advanced information on managing these keys, as the example shown is simplified for clarity.\u003c/p\u003e\n"]]],[],null,[]]
