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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 prior versions such as 2.36.0, 2.35.0, etc., all the way down to 2.12.0, also being accessible.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries utilize Application Default Credentials (ADC) for Google Cloud Services authentication, but you can override this setting when needed.\u003c/p\u003e\n"],["\u003cp\u003eOverriding default credentials can be done using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, demonstrated through an example that loads a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples are provided for multiple \u003ccode\u003e*Client\u003c/code\u003e classes, such as \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, all under version 2.14.0.\u003c/p\u003e\n"],["\u003cp\u003eFor more information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, refer to the "Authentication Components" documentation.\u003c/p\u003e\n"]]],[],null,[]]
