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 2025-03-14 UTC."],[[["The latest release candidate version is 2.37.0-rc, and multiple previous versions from 2.36.0 down to 2.11.0 are also available for selection."],["Client libraries primarily utilize Application Default Credentials for authentication with Google Cloud Services, but this can be overridden."],["You can override the default authentication by supplying a `UnifiedCredentialsOption`, which enables the loading of a service account key file."],["The provided code example demonstrates how to load a service account key file and create a DocumentProcessorServiceClient using the `MakeServiceAccountCredentials` function."],["Consult the \"Best practices for managing service account keys\" guide for in-depth information, and check out \"Authentication Components\" for more details on creating `google::cloud::Credentials` objects."]]],[]]