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::sql_v1::SqlBackupRunsServiceClient(
google::cloud::sql_v1::MakeSqlBackupRunsServiceConnectionRest(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 details how to override the default Application Default Credentials (ADC) for authenticating with Google Cloud Services using the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the documentation provided is 2.37.0-rc, and it includes a list of other versions dating back to 2.11.0, all linking to documentation on overriding authentication.\u003c/p\u003e\n"],["\u003cp\u003eOverriding the default credentials can be accomplished by loading a service account key file using the provided example code snippet and the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe documentation includes links to code examples for multiple \u003ccode\u003e*Client\u003c/code\u003e classes, such as \u003ccode\u003eSqlBackupRunsServiceClient\u003c/code\u003e, \u003ccode\u003eSqlConnectServiceClient\u003c/code\u003e, and \u003ccode\u003eSqlUsersServiceClient\u003c/code\u003e, all at version 2.19.0.\u003c/p\u003e\n"],["\u003cp\u003eFor best practices in managing service account keys and additional information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, external resources are provided.\u003c/p\u003e\n"]]],[],null,["Version 2.19.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/sql/latest/sql-override-authentication)\n- [2.41.0](/cpp/docs/reference/sql/2.41.0/sql-override-authentication)\n- [2.40.0](/cpp/docs/reference/sql/2.40.0/sql-override-authentication)\n- [2.39.0](/cpp/docs/reference/sql/2.39.0/sql-override-authentication)\n- [2.38.0](/cpp/docs/reference/sql/2.38.0/sql-override-authentication)\n- [2.37.0](/cpp/docs/reference/sql/2.37.0/sql-override-authentication)\n- [2.36.0](/cpp/docs/reference/sql/2.36.0/sql-override-authentication)\n- [2.35.0](/cpp/docs/reference/sql/2.35.0/sql-override-authentication)\n- [2.34.0](/cpp/docs/reference/sql/2.34.0/sql-override-authentication)\n- [2.33.0](/cpp/docs/reference/sql/2.33.0/sql-override-authentication)\n- [2.32.0](/cpp/docs/reference/sql/2.32.0/sql-override-authentication)\n- [2.31.0](/cpp/docs/reference/sql/2.31.0/sql-override-authentication)\n- [2.30.0](/cpp/docs/reference/sql/2.30.0/sql-override-authentication)\n- [2.29.0](/cpp/docs/reference/sql/2.29.0/sql-override-authentication)\n- [2.28.0](/cpp/docs/reference/sql/2.28.0/sql-override-authentication)\n- [2.27.0](/cpp/docs/reference/sql/2.27.0/sql-override-authentication)\n- [2.26.0](/cpp/docs/reference/sql/2.26.0/sql-override-authentication)\n- [2.25.1](/cpp/docs/reference/sql/2.25.1/sql-override-authentication)\n- [2.24.0](/cpp/docs/reference/sql/2.24.0/sql-override-authentication)\n- [2.23.0](/cpp/docs/reference/sql/2.23.0/sql-override-authentication)\n- [2.22.1](/cpp/docs/reference/sql/2.22.1/sql-override-authentication)\n- [2.21.0](/cpp/docs/reference/sql/2.21.0/sql-override-authentication)\n- [2.20.0](/cpp/docs/reference/sql/2.20.0/sql-override-authentication)\n- [2.19.0](/cpp/docs/reference/sql/2.19.0/sql-override-authentication)\n- [2.18.0](/cpp/docs/reference/sql/2.18.0/sql-override-authentication)\n- [2.17.0](/cpp/docs/reference/sql/2.17.0/sql-override-authentication)\n- [2.16.0](/cpp/docs/reference/sql/2.16.0/sql-override-authentication)\n- [2.15.1](/cpp/docs/reference/sql/2.15.1/sql-override-authentication)\n- [2.14.0](/cpp/docs/reference/sql/2.14.0/sql-override-authentication)\n- [2.13.0](/cpp/docs/reference/sql/2.13.0/sql-override-authentication)\n- [2.12.0](/cpp/docs/reference/sql/2.12.0/sql-override-authentication)\n- [2.11.0](/cpp/docs/reference/sql/2.11.0/sql-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::sql_v1::SqlBackupRunsServiceClient(\n google::cloud::sql_v1::MakeSqlBackupRunsServiceConnectionRest(options));\n }\n\nFollow these links to find examples for other `*Client` classes:\n\n- [`sql_v1::SqlBackupRunsServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlBackupRunsServiceClient-service-account-snippet)\n- [`sql_v1::SqlConnectServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlConnectServiceClient-service-account-snippet)\n- [`sql_v1::SqlDatabasesServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlDatabasesServiceClient-service-account-snippet)\n- [`sql_v1::SqlFlagsServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlFlagsServiceClient-service-account-snippet)\n- [`sql_v1::SqlInstancesServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlInstancesServiceClient-service-account-snippet)\n- [`sql_v1::SqlOperationsServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlOperationsServiceClient-service-account-snippet)\n- [`sql_v1::SqlSslCertsServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlSslCertsServiceClient-service-account-snippet)\n- [`sql_v1::SqlTiersServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlTiersServiceClient-service-account-snippet)\n- [`sql_v1::SqlUsersServiceClient`](/cpp/docs/reference/sql/2.19.0/sql_v1_1_1SqlUsersServiceClient-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."]]