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 the Eventarc C++ client library, including a list of available versions ranging from 2.11.0 to 2.37.0-rc, with 2.37.0-rc being the latest release candidate.\u003c/p\u003e\n"],["\u003cp\u003eThe library defaults to using Application Default Credentials (ADC) for authentication with Google Cloud Services, but you can override these credentials by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe page includes a code example demonstrating how to load a service account key file to explicitly set authentication credentials when instantiating the client.\u003c/p\u003e\n"],["\u003cp\u003eExample code snippets are provided for both the \u003ccode\u003eeventarc_publishing_v1::PublisherClient\u003c/code\u003e and \u003ccode\u003eeventarc_v1::EventarcClient\u003c/code\u003e classes, showcasing how to override credentials.\u003c/p\u003e\n"],["\u003cp\u003eFor best practices and more information on managing service account keys, a link to the official Google Cloud guide is included.\u003c/p\u003e\n"]]],[],null,["Version 2.11.0keyboard_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/2.11.0/eventarc_publishing_v1_1_1PublisherClient-service-account-snippet)\n- [`eventarc_v1::EventarcClient`](/cpp/docs/reference/eventarc/2.11.0/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."]]