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::servicecontrol_v1::QuotaControllerClient(
google::cloud::servicecontrol_v1::MakeQuotaControllerConnection(
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 version history and documentation for overriding authentication credentials in Google Cloud C++ client libraries, starting with version 2.12.0 and including the latest release candidate 2.37.0-rc."],["By default, client libraries utilize Application Default Credentials for authentication, but users can override this using the `UnifiedCredentialsOption` to specify credentials explicitly."],["The provided example demonstrates how to load a service account key file to override the default credentials, setting it within the options for the client."],["Specific examples are given for `QuotaControllerClient`, `ServiceControllerClient` (v1 and v2) classes, showing how to apply service account credentials, with a link to the related snippet for each."],["For details on managing service account keys, the document directs users to the \"Best practices for managing service account keys\" guide, as well as the \"Authentication Components\" for creating credentials objects."]]],[]]
