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::documentai_v1::DocumentProcessorServiceClient(
google::cloud::documentai_v1::MakeDocumentProcessorServiceConnection(
options));
}
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-04-17 UTC."],[[["This page provides documentation for various versions of the Document AI C++ client library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc."],["The default authentication for the client libraries uses Application Default Credentials, but it can be overridden when necessary."],["You can override the default authentication by utilizing the `UnifiedCredentialsOption` and providing it with the service account key file, as shown in the provided code example."],["For more in-depth details on handling service account keys and authentication, you can refer to the 'Best practices for managing service account keys' guide and the 'Authentication Components' section."]]],[]]
