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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 focusing on the \u003ccode\u003ecomposer\u003c/code\u003e service.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version is 2.37.0-rc, and there are numerous documented versions available, ranging from 2.11.0 up to 2.36.0.\u003c/p\u003e\n"],["\u003cp\u003eThe example code demonstrates how to load a service account key file and use it to set the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, which can then be used to create a \u003ccode\u003eEnvironmentsClient\u003c/code\u003e instance.\u003c/p\u003e\n"],["\u003cp\u003eSpecific examples are available for \u003ccode\u003ecomposer_v1::EnvironmentsClient\u003c/code\u003e and \u003ccode\u003ecomposer_v1::ImageVersionsClient\u003c/code\u003e classes to show how to apply the override method.\u003c/p\u003e\n"],["\u003cp\u003eFor details on managing service account keys or creating credentials objects, users should consult the provided links to the best practices guide and the authentication components documentation, respectively.\u003c/p\u003e\n"]]],[],null,[]]
