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 a version history, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc, for the C++ client library's Vision API documentation."],["The latest version of the documentation provided is 2.37.0-rc, which is a release candidate version."],["The documentation details how to override the default authentication credentials used by the client libraries, which typically default to Application Default Credentials (ADC)."],["Overriding authentication can be achieved by providing the `UnifiedCredentialsOption` and it demonstrates how to explicitly load a service account key file."],["Examples are provided for how to override the authentication credentials for two client classes: `vision_v1::ImageAnnotatorClient` and `vision_v1::ProductSearchClient`."]]],[]]
