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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 multiple other versions from 2.36.0 to 2.12.0 also accessible through the provided links.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries use Application Default Credentials for Google Cloud Service authentication, but this can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication by utilizing the UnifiedCredentialsOption and can be demonstrated by loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThere are multiple links to examples for different \u003ccode\u003e*Client\u003c/code\u003e classes such as \u003ccode\u003econtentwarehouse_v1::DocumentServiceClient\u003c/code\u003e, \u003ccode\u003econtentwarehouse_v1::DocumentLinkServiceClient\u003c/code\u003e, and others.\u003c/p\u003e\n"],["\u003cp\u003eFor detailed information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, refer to the Authentication Components section.\u003c/p\u003e\n"]]],[],null,[]]
