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"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThis document provides a reference for various versions of channel authentication, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries generally use Application Default Credentials for authentication, but these defaults can be overridden as needed.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication override is possible by providing a \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, which is illustrated with an example of loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThere are links to examples for other \u003ccode\u003e*Client\u003c/code\u003e classes like \u003ccode\u003echannel_v1::CloudChannelServiceClient\u003c/code\u003e and \u003ccode\u003echannel_v1::CloudChannelReportsServiceClient\u003c/code\u003e for version 2.23.0.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on authentication and creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, you can refer to the "Authentication Components" section.\u003c/p\u003e\n"]]],[],null,[]]
