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::commerce_consumer_procurement_v1::
ConsumerProcurementServiceClient(
google::cloud::commerce_consumer_procurement_v1::
MakeConsumerProcurementServiceConnection(options));
}
[[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 provides guidance on overriding default authentication credentials when using Google Cloud client libraries, particularly for the C++ Commerce API.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the C++ Commerce API documentation available is 2.37.0-rc, and many previous versions are also available, going back to 2.14.0.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default credentials by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and explicitly loading a service account key file, as shown in the provided example.\u003c/p\u003e\n"],["\u003cp\u003eThe document highlights the use of \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e to load the service account key file for \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and to use \u003ccode\u003egoogle::cloud::Options\u003c/code\u003e to set it.\u003c/p\u003e\n"],["\u003cp\u003eFurther details on managing service account keys and authentication components can be found in the "Best practices for managing service account keys" and "Authentication Components" documentation links respectively.\u003c/p\u003e\n"]]],[],null,[]]
