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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 provides documentation for overriding default authentication credentials when using Google Cloud client libraries, specifically for the Composer service.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version documentation available is for version 2.37.0-rc, and documentation spans back to version 2.11.0, with a variety of versions in between.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication can be overridden by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e to explicitly load a service account key file, as demonstrated in the provided example.\u003c/p\u003e\n"],["\u003cp\u003eExamples of overriding authentication for \u003ccode\u003ecomposer_v1::EnvironmentsClient\u003c/code\u003e and \u003ccode\u003ecomposer_v1::ImageVersionsClient\u003c/code\u003e are available via the provided links.\u003c/p\u003e\n"],["\u003cp\u003eFor detailed guidance on service account key management, users are referred to the "Best practices for managing service account keys" guide, and more information about credentials can be found in the "Authentication Components" section.\u003c/p\u003e\n"]]],[],null,[]]
