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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page provides documentation for overriding default authentication credentials when using Google Cloud client libraries, specifically focusing on the \u003ccode\u003echannel\u003c/code\u003e service.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version is 2.37.0-rc, while 2.36.0 is the most current stable release with links to all documented versions down to version 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eUsers can override the default credentials by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing their service account key file's contents.\u003c/p\u003e\n"],["\u003cp\u003eExample code is given on how to do it with the \u003ccode\u003echannel_v1::CloudChannelServiceClient\u003c/code\u003e and the \u003ccode\u003echannel_v1::CloudChannelReportsServiceClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe page links to further resources, like best practices for managing service account keys and more information on creating \u003ccode\u003eCredentials\u003c/code\u003e objects, for more details.\u003c/p\u003e\n"]]],[],null,[]]
