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::eventarc_publishing_v1::PublisherClient(
google::cloud::eventarc_publishing_v1::MakePublisherConnection(
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 Eventarc C++ client library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries typically use Application Default Credentials for authentication, but can be overridden using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e to specify alternative credentials.\u003c/p\u003e\n"],["\u003cp\u003eA service account key file can be explicitly loaded to override default credentials, as demonstrated in the provided example using \u003ccode\u003eMakeServiceAccountCredentials\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eSpecific examples for \u003ccode\u003eeventarc_publishing_v1::PublisherClient\u003c/code\u003e and \u003ccode\u003eeventarc_v1::EventarcClient\u003c/code\u003e regarding service account usage are available through provided links.\u003c/p\u003e\n"],["\u003cp\u003eRefer to the "Best practices for managing service account keys" and "Authentication Components" for further details and alternative methods to manage credentials.\u003c/p\u003e\n"]]],[],null,["Version 2.21.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/eventarc/latest/eventarc-override-authentication)\n- [2.41.0](/cpp/docs/reference/eventarc/2.41.0/eventarc-override-authentication)\n- [2.40.0](/cpp/docs/reference/eventarc/2.40.0/eventarc-override-authentication)\n- [2.39.0](/cpp/docs/reference/eventarc/2.39.0/eventarc-override-authentication)\n- [2.38.0](/cpp/docs/reference/eventarc/2.38.0/eventarc-override-authentication)\n- [2.37.0](/cpp/docs/reference/eventarc/2.37.0/eventarc-override-authentication)\n- [2.36.0](/cpp/docs/reference/eventarc/2.36.0/eventarc-override-authentication)\n- [2.35.0](/cpp/docs/reference/eventarc/2.35.0/eventarc-override-authentication)\n- [2.34.0](/cpp/docs/reference/eventarc/2.34.0/eventarc-override-authentication)\n- [2.33.0](/cpp/docs/reference/eventarc/2.33.0/eventarc-override-authentication)\n- [2.32.0](/cpp/docs/reference/eventarc/2.32.0/eventarc-override-authentication)\n- [2.31.0](/cpp/docs/reference/eventarc/2.31.0/eventarc-override-authentication)\n- [2.30.0](/cpp/docs/reference/eventarc/2.30.0/eventarc-override-authentication)\n- [2.29.0](/cpp/docs/reference/eventarc/2.29.0/eventarc-override-authentication)\n- [2.28.0](/cpp/docs/reference/eventarc/2.28.0/eventarc-override-authentication)\n- [2.27.0](/cpp/docs/reference/eventarc/2.27.0/eventarc-override-authentication)\n- [2.26.0](/cpp/docs/reference/eventarc/2.26.0/eventarc-override-authentication)\n- [2.25.1](/cpp/docs/reference/eventarc/2.25.1/eventarc-override-authentication)\n- [2.24.0](/cpp/docs/reference/eventarc/2.24.0/eventarc-override-authentication)\n- [2.23.0](/cpp/docs/reference/eventarc/2.23.0/eventarc-override-authentication)\n- [2.22.1](/cpp/docs/reference/eventarc/2.22.1/eventarc-override-authentication)\n- [2.21.0](/cpp/docs/reference/eventarc/2.21.0/eventarc-override-authentication)\n- [2.20.0](/cpp/docs/reference/eventarc/2.20.0/eventarc-override-authentication)\n- [2.19.0](/cpp/docs/reference/eventarc/2.19.0/eventarc-override-authentication)\n- [2.18.0](/cpp/docs/reference/eventarc/2.18.0/eventarc-override-authentication)\n- [2.17.0](/cpp/docs/reference/eventarc/2.17.0/eventarc-override-authentication)\n- [2.16.0](/cpp/docs/reference/eventarc/2.16.0/eventarc-override-authentication)\n- [2.15.1](/cpp/docs/reference/eventarc/2.15.1/eventarc-override-authentication)\n- [2.14.0](/cpp/docs/reference/eventarc/2.14.0/eventarc-override-authentication)\n- [2.13.0](/cpp/docs/reference/eventarc/2.13.0/eventarc-override-authentication)\n- [2.12.0](/cpp/docs/reference/eventarc/2.12.0/eventarc-override-authentication)\n- [2.11.0](/cpp/docs/reference/eventarc/2.11.0/eventarc-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::eventarc_publishing_v1::PublisherClient(\n google::cloud::eventarc_publishing_v1::MakePublisherConnection(\n options));\n }\n\nFollow these links to find examples for other `*Client` classes:\n\n- [`eventarc_publishing_v1::PublisherClient`](/cpp/docs/reference/eventarc/2.21.0/eventarc_publishing_v1_1_1PublisherClient-service-account-snippet)\n- [`eventarc_v1::EventarcClient`](/cpp/docs/reference/eventarc/2.21.0/eventarc_v1_1_1EventarcClient-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."]]