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::redis_cluster_v1::CloudRedisClusterClient(
google::cloud::redis_cluster_v1::MakeCloudRedisClusterConnection(
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 document provides guidance on overriding default authentication credentials when using Google Cloud client libraries for C++.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version is 2.37.0-rc, but the current version used in this page example is 2.32.0.\u003c/p\u003e\n"],["\u003cp\u003eOverriding authentication can be achieved by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and explicitly loading a service account key file, as demonstrated in the provided code snippet.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries default to using Application Default Credentials for authentication unless a different method is configured.\u003c/p\u003e\n"],["\u003cp\u003eExamples of how to override credentials for \u003ccode\u003eredis_cluster_v1::CloudRedisClusterClient\u003c/code\u003e and \u003ccode\u003eredis_v1::CloudRedisClient\u003c/code\u003e classes are also provided, and users are encouraged to consult best practices for service account key management.\u003c/p\u003e\n"]]],[],null,["Version 2.32.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/redis/latest/redis-override-authentication)\n- [2.41.0](/cpp/docs/reference/redis/2.41.0/redis-override-authentication)\n- [2.40.0](/cpp/docs/reference/redis/2.40.0/redis-override-authentication)\n- [2.39.0](/cpp/docs/reference/redis/2.39.0/redis-override-authentication)\n- [2.38.0](/cpp/docs/reference/redis/2.38.0/redis-override-authentication)\n- [2.37.0](/cpp/docs/reference/redis/2.37.0/redis-override-authentication)\n- [2.36.0](/cpp/docs/reference/redis/2.36.0/redis-override-authentication)\n- [2.35.0](/cpp/docs/reference/redis/2.35.0/redis-override-authentication)\n- [2.34.0](/cpp/docs/reference/redis/2.34.0/redis-override-authentication)\n- [2.33.0](/cpp/docs/reference/redis/2.33.0/redis-override-authentication)\n- [2.32.0](/cpp/docs/reference/redis/2.32.0/redis-override-authentication)\n- [2.31.0](/cpp/docs/reference/redis/2.31.0/redis-override-authentication)\n- [2.30.0](/cpp/docs/reference/redis/2.30.0/redis-override-authentication)\n- [2.29.0](/cpp/docs/reference/redis/2.29.0/redis-override-authentication)\n- [2.28.0](/cpp/docs/reference/redis/2.28.0/redis-override-authentication)\n- [2.27.0](/cpp/docs/reference/redis/2.27.0/redis-override-authentication)\n- [2.26.0](/cpp/docs/reference/redis/2.26.0/redis-override-authentication)\n- [2.25.1](/cpp/docs/reference/redis/2.25.1/redis-override-authentication)\n- [2.24.0](/cpp/docs/reference/redis/2.24.0/redis-override-authentication)\n- [2.23.0](/cpp/docs/reference/redis/2.23.0/redis-override-authentication)\n- [2.22.1](/cpp/docs/reference/redis/2.22.1/redis-override-authentication)\n- [2.21.0](/cpp/docs/reference/redis/2.21.0/redis-override-authentication)\n- [2.20.0](/cpp/docs/reference/redis/2.20.0/redis-override-authentication)\n- [2.19.0](/cpp/docs/reference/redis/2.19.0/redis-override-authentication)\n- [2.18.0](/cpp/docs/reference/redis/2.18.0/redis-override-authentication)\n- [2.17.0](/cpp/docs/reference/redis/2.17.0/redis-override-authentication)\n- [2.16.0](/cpp/docs/reference/redis/2.16.0/redis-override-authentication)\n- [2.15.1](/cpp/docs/reference/redis/2.15.1/redis-override-authentication)\n- [2.14.0](/cpp/docs/reference/redis/2.14.0/redis-override-authentication)\n- [2.13.0](/cpp/docs/reference/redis/2.13.0/redis-override-authentication)\n- [2.12.0](/cpp/docs/reference/redis/2.12.0/redis-override-authentication)\n- [2.11.0](/cpp/docs/reference/redis/2.11.0/redis-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::redis_cluster_v1::CloudRedisClusterClient(\n google::cloud::redis_cluster_v1::MakeCloudRedisClusterConnection(\n options));\n }\n\nFollow these links to find examples for other `*Client` classes:\n\n- [`redis_cluster_v1::CloudRedisClusterClient`](/cpp/docs/reference/redis/2.32.0/redis_cluster_v1_1_1CloudRedisClusterClient-service-account-snippet)\n- [`redis_v1::CloudRedisClient`](/cpp/docs/reference/redis/2.32.0/redis_v1_1_1CloudRedisClient-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."]]