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::channel_v1::CloudChannelServiceClient(
google::cloud::channel_v1::MakeCloudChannelServiceConnection(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 2025-08-14 UTC."],[[["\u003cp\u003eThis document details how to override the default authentication credentials for Google Cloud Services, which typically use Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version available is 2.37.0-rc, and the content includes versioned documentation for releases from 2.11.0 up to the latest.\u003c/p\u003e\n"],["\u003cp\u003eOverriding the authentication can be accomplished by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e to explicitly load a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples are provided for the \u003ccode\u003echannel_v1::CloudChannelServiceClient\u003c/code\u003e and \u003ccode\u003echannel_v1::CloudChannelReportsServiceClient\u003c/code\u003e classes, demonstrating how to override authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe document references external resources for more in-depth information, including best practices for managing service account keys and a guide on authentication components.\u003c/p\u003e\n"]]],[],null,[]]
