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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 client libraries, specifically using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate is version 2.37.0-rc, with many prior versions listed from 2.36.0 down to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example demonstrates how to load a service account key file explicitly to override the default credentials.\u003c/p\u003e\n"],["\u003cp\u003eThere are code snippets for the \u003ccode\u003ecomposer_v1::EnvironmentsClient\u003c/code\u003e and \u003ccode\u003ecomposer_v1::ImageVersionsClient\u003c/code\u003e to give concrete examples of usage.\u003c/p\u003e\n"],["\u003cp\u003eThe page also provides links to further resources, including best practices for managing service account keys and the authentication components reference.\u003c/p\u003e\n"]]],[],null,[]]
