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\u003eThis page provides documentation for various versions of the C++ client library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc, including specific links for the \u003ccode\u003eiap-override-authentication\u003c/code\u003e feature for each version.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries primarily use Application Default Credentials for authentication with Google Cloud Services, which works in most applications, but there is also the option to override these with other methods.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication can be overridden by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, and an example is shown on how to explicitly load a service account key file through this method, using \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eSpecific examples for other client classes, namely \u003ccode\u003eiap_v1::IdentityAwareProxyAdminServiceClient\u003c/code\u003e and \u003ccode\u003eiap_v1::IdentityAwareProxyOAuthServiceClient\u003c/code\u003e, are available via the provided links.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ca href=\"https://cloud.google.com/cpp/docs/reference/common/latest/group__guac.html\"\u003eAuthentication Components\u003c/a\u003e guide provides extra resources on how to create \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,["Version 2.34.0keyboard_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/2.34.0/iap_v1_1_1IdentityAwareProxyAdminServiceClient-service-account-snippet)\n- [`iap_v1::IdentityAwareProxyOAuthServiceClient`](/cpp/docs/reference/iap/2.34.0/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."]]