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::workflows_executions_v1::ExecutionsClient(
google::cloud::workflows_executions_v1::MakeExecutionsConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 document 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 authentication by using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing credentials like a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the documentation is for version 2.37.0-rc, with a range of documentation versions provided, starting from 2.11.0 and continuing up to 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eExamples are provided for \u003ccode\u003eworkflows_executions_v1::ExecutionsClient\u003c/code\u003e and \u003ccode\u003eworkflows_v1::WorkflowsClient\u003c/code\u003e to demonstrate how to load service account credentials.\u003c/p\u003e\n"],["\u003cp\u003eIt's recommended to follow the "Best practices for managing service account keys" guide and the "Authentication Components" for more information on managing credentials.\u003c/p\u003e\n"]]],[],null,[]]
