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 2025-03-21 UTC."],[[["This document provides a guide on how to override default authentication credentials when using Google Cloud C++ client libraries, which typically rely on Application Default Credentials."],["The latest available version is `2.37.0-rc`, and there is a list of previous versions starting from `2.36.0` down to `2.11.0` for users to reference."],["Users can override the default credentials by providing a `UnifiedCredentialsOption`, such as loading a service account key file, which is demonstrated with example code."],["The document provides links to examples for `vision_v1::ImageAnnotatorClient` and `vision_v1::ProductSearchClient`, and directs the user to best practices for managing service account keys."],["Additional information about creating `google::cloud::Credentials` objects can be found under the Authentication Components section."]]],[]]
