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 webpage 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 primary focus is on how to override the default authentication credentials, which typically rely on Application Default Credentials (ADC)."],["Users can override the default credentials by using `UnifiedCredentialsOption` and explicitly loading a service account key file, as shown in the provided C++ example."],["The documentation references best practices for managing service account keys and provides links to further information on authentication components."],["The provided example demonstrates minimal error handling, however, it is recommended that users refer to the guide on service account key management for more detail."]]],[]]
