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 webpage provides documentation for the Eventarc C++ client library, including version-specific documentation, with the latest release candidate being version 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe content primarily focuses on how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e in the Eventarc C++ client library.\u003c/p\u003e\n"],["\u003cp\u003eAn example is provided demonstrating how to explicitly load a service account key file for authentication, using \u003ccode\u003egoogle::cloud::MakeServiceAccountCredentials\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation offers examples for other \u003ccode\u003e*Client\u003c/code\u003e classes, including \u003ccode\u003eeventarc_publishing_v1::PublisherClient\u003c/code\u003e and \u003ccode\u003eeventarc_v1::EventarcClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThere is a \u003ccode\u003eSee Also\u003c/code\u003e section that directs users to the \u003ccode\u003eAuthentication Components\u003c/code\u003e documentation for more information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,["Version 2.12.0keyboard_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/2.12.0/eventarc_publishing_v1_1_1PublisherClient-service-account-snippet)\n- [`eventarc_v1::EventarcClient`](/cpp/docs/reference/eventarc/2.12.0/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."]]