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::iap_v1::IdentityAwareProxyAdminServiceClient(
google::cloud::iap_v1::MakeIdentityAwareProxyAdminServiceConnection(
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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThe latest release candidate version is 2.37.0-rc, with previous versions ranging from 2.36.0 down to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eClient libraries default to using Application Default Credentials for Google Cloud Services authentication, but this can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication can be overridden using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated by the example that shows how to load a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples of how to override authentication credentials for \u003ccode\u003eiap_v1::IdentityAwareProxyAdminServiceClient\u003c/code\u003e and \u003ccode\u003eiap_v1::IdentityAwareProxyOAuthServiceClient\u003c/code\u003e are provided.\u003c/p\u003e\n"],["\u003cp\u003eUsers are encouraged to review the best practices guide for managing service account keys for further guidance on managing keys.\u003c/p\u003e\n"]]],[],null,[]]
