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."],[[["The webpage provides documentation for various versions of the C++ Vision API, ranging from version 2.11.0 to the latest release candidate 2.37.0-rc."],["The default authentication method for the client libraries is Application Default Credentials, but this can be overridden when needed."],["Users can override the default authentication by utilizing the `UnifiedCredentialsOption` to explicitly load a service account key file."],["Examples for using a service account key with `vision_v1::ImageAnnotatorClient` and `vision_v1::ProductSearchClient` are provided on the page."],["The page also directs users to a best practices guide for managing service account keys, as well as providing more information on authentication components."]]],[]]
