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::composer_v1::EnvironmentsClient(
google::cloud::composer_v1::MakeEnvironmentsConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 details how to override the default authentication credentials for Google Cloud services, which typically use Application Default Credentials (ADC).\u003c/p\u003e\n"],["\u003cp\u003eUsers can override the default credentials by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing specific credentials, such as those from a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example demonstrates how to load and utilize a service account key file to authenticate, with code examples using the \u003ccode\u003eEnvironmentsClient\u003c/code\u003e and \u003ccode\u003eImageVersionsClient\u003c/code\u003e classes.\u003c/p\u003e\n"],["\u003cp\u003eThe page also covers many versions of the library, with the latest version being 2.37.0-rc, and the current focused version being 2.36.0.\u003c/p\u003e\n"],["\u003cp\u003eUsers are advised to consult the "Best practices for managing service account keys" guide for more in-depth information on managing these keys securely.\u003c/p\u003e\n"]]],[],null,[]]
