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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page provides documentation for overriding default authentication credentials when using Google Cloud client libraries, which typically rely on Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing service account credentials, such as loading them from a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation includes a code example that shows how to explicitly load a service account key file for authentication, demonstrating the override process.\u003c/p\u003e\n"],["\u003cp\u003eLinks are provided to examples that demonstrate overriding authentication for various \u003ccode\u003e*Client\u003c/code\u003e classes, like \u003ccode\u003eDocumentServiceClient\u003c/code\u003e, \u003ccode\u003eDocumentLinkServiceClient\u003c/code\u003e, and others, found within the \u003ccode\u003econtentwarehouse_v1\u003c/code\u003e namespace.\u003c/p\u003e\n"],["\u003cp\u003eThe page references best practices for managing service account keys and offers links for more information on \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects and authentication component factory functions.\u003c/p\u003e\n"]]],[],null,[]]
