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::vision_v1::ImageAnnotatorClient(
google::cloud::vision_v1::MakeImageAnnotatorConnection(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"]],[["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."],[[["This document provides guidance on overriding default authentication credentials when interacting with Google Cloud Services, particularly in C++."],["The latest release candidate is version 2.37.0-rc, and the currently presented content relates to version 2.26.0."],["Developers can override the default authentication by using `UnifiedCredentialsOption` and providing a service account key file, as shown in the code example."],["The provided resources include links to code snippets for `vision_v1::ImageAnnotatorClient` and `vision_v1::ProductSearchClient`, alongside a guide on best practices for managing service account keys."],["The document provides a comprehensive list of previous versions of the API from version 2.11.0 up to the latest release."]]],[]]