Unless otherwise configured, the client libraries useApplication Default Credentialsto 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 theUnifiedCredentialsOptionThe 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*Clientclasses:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThe latest version available is 2.37.0-rc, with numerous previous versions dating back to 2.11.0 also accessible for reference.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries utilize Application Default Credentials for Google Cloud Service authentication, but this can be overridden when needed.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication credentials can be overridden using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated by loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eExamples of credential overriding are available for both \u003ccode\u003eiap_v1::IdentityAwareProxyAdminServiceClient\u003c/code\u003e and \u003ccode\u003eiap_v1::IdentityAwareProxyOAuthServiceClient\u003c/code\u003e classes.\u003c/p\u003e\n"],["\u003cp\u003eFor details regarding the management of service account keys, the documentation recommends the "Best practices for managing service account keys" guide, while additional information on \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects is available in "Authentication Components".\u003c/p\u003e\n"]]],[],null,["Version 2.30.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/iap/latest/iap-override-authentication)\n- [2.41.0](/cpp/docs/reference/iap/2.41.0/iap-override-authentication)\n- [2.40.0](/cpp/docs/reference/iap/2.40.0/iap-override-authentication)\n- [2.39.0](/cpp/docs/reference/iap/2.39.0/iap-override-authentication)\n- [2.38.0](/cpp/docs/reference/iap/2.38.0/iap-override-authentication)\n- [2.37.0](/cpp/docs/reference/iap/2.37.0/iap-override-authentication)\n- [2.36.0](/cpp/docs/reference/iap/2.36.0/iap-override-authentication)\n- [2.35.0](/cpp/docs/reference/iap/2.35.0/iap-override-authentication)\n- [2.34.0](/cpp/docs/reference/iap/2.34.0/iap-override-authentication)\n- [2.33.0](/cpp/docs/reference/iap/2.33.0/iap-override-authentication)\n- [2.32.0](/cpp/docs/reference/iap/2.32.0/iap-override-authentication)\n- [2.31.0](/cpp/docs/reference/iap/2.31.0/iap-override-authentication)\n- [2.30.0](/cpp/docs/reference/iap/2.30.0/iap-override-authentication)\n- [2.29.0](/cpp/docs/reference/iap/2.29.0/iap-override-authentication)\n- [2.28.0](/cpp/docs/reference/iap/2.28.0/iap-override-authentication)\n- [2.27.0](/cpp/docs/reference/iap/2.27.0/iap-override-authentication)\n- [2.26.0](/cpp/docs/reference/iap/2.26.0/iap-override-authentication)\n- [2.25.1](/cpp/docs/reference/iap/2.25.1/iap-override-authentication)\n- [2.24.0](/cpp/docs/reference/iap/2.24.0/iap-override-authentication)\n- [2.23.0](/cpp/docs/reference/iap/2.23.0/iap-override-authentication)\n- [2.22.1](/cpp/docs/reference/iap/2.22.1/iap-override-authentication)\n- [2.21.0](/cpp/docs/reference/iap/2.21.0/iap-override-authentication)\n- [2.20.0](/cpp/docs/reference/iap/2.20.0/iap-override-authentication)\n- [2.19.0](/cpp/docs/reference/iap/2.19.0/iap-override-authentication)\n- [2.18.0](/cpp/docs/reference/iap/2.18.0/iap-override-authentication)\n- [2.17.0](/cpp/docs/reference/iap/2.17.0/iap-override-authentication)\n- [2.16.0](/cpp/docs/reference/iap/2.16.0/iap-override-authentication)\n- [2.15.1](/cpp/docs/reference/iap/2.15.1/iap-override-authentication)\n- [2.14.0](/cpp/docs/reference/iap/2.14.0/iap-override-authentication)\n- [2.13.0](/cpp/docs/reference/iap/2.13.0/iap-override-authentication)\n- [2.12.0](/cpp/docs/reference/iap/2.12.0/iap-override-authentication)\n- [2.11.0](/cpp/docs/reference/iap/2.11.0/iap-override-authentication) \n\nHow to Override the Authentication Credentials\n==============================================\n\nUnless otherwise configured, the client libraries use [Application Default Credentials](https://cloud.google.com/docs/authentication#adc) 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](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1UnifiedCredentialsOption.html) The following example shows how to explicitly load a service account key file: \n\n [](std::string const& keyfile) {\n auto is = std::ifstream(keyfile);\n is.exceptions(std::ios::badbit); // Minimal error handling in examples\n auto contents = std::string(std::istreambuf_iterator\u003cchar\u003e(is.rdbuf()), {});\n auto options =\n google::cloud::Options{}.set\u003cgoogle::cloud::UnifiedCredentialsOption\u003e(\n google::cloud::MakeServiceAccountCredentials(contents));\n return google::cloud::iap_v1::IdentityAwareProxyAdminServiceClient(\n google::cloud::iap_v1::MakeIdentityAwareProxyAdminServiceConnection(\n options));\n }\n\nFollow these links to find examples for other `*Client` classes:\n\n- [`iap_v1::IdentityAwareProxyAdminServiceClient`](/cpp/docs/reference/iap/2.30.0/iap_v1_1_1IdentityAwareProxyAdminServiceClient-service-account-snippet)\n- [`iap_v1::IdentityAwareProxyOAuthServiceClient`](/cpp/docs/reference/iap/2.30.0/iap_v1_1_1IdentityAwareProxyOAuthServiceClient-service-account-snippet)\n\nKeep in mind that we chose this as an example because it is relatively easy to understand. Consult the [Best practices for managing service account keys](https://cloud.google.com/iam/docs/best-practices-for-managing-service-account-keys) guide for more details.\n\n###### See Also\n\n[Authentication Components](https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html) - for more information on the factory functions to create [`google::cloud::Credentials`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1Credentials.html) objects."]]