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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThe latest release candidate version is 2.37.0-rc, and a range of prior versions are available, starting from version 2.14.0 up to the latest.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries authenticate using Application Default Credentials, but you can override this setting when needed.\u003c/p\u003e\n"],["\u003cp\u003eOverriding default authentication can be done by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e with explicit credentials, such as loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example details how to use \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e to explicitly load a service account key file for authentication, for more information on authentication credentials, see the \u003ccode\u003eAuthentication Components\u003c/code\u003e section.\u003c/p\u003e\n"],["\u003cp\u003eIt is advised to consult the "Best practices for managing service account keys" guide for more information on best practices regarding service account keys.\u003c/p\u003e\n"]]],[],null,[]]
