[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThis page provides documentation and examples for managing authentication configurations in the Google Cloud C++ Bigtable client library, specifically focusing on overriding default settings.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release of the Bigtable C++ library is version 2.37.0-rc, with the example code demonstrating overriding the default authentication method using a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003egoogle::cloud::UnifiedCredentialsOption\u003c/code\u003e can be used to replace the default configuration when you load your own credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe examples show how to load a service account key file to replace the default authentication, which is shown to be an easy to understand example.\u003c/p\u003e\n"],["\u003cp\u003eSimilar authentication configuration overrides can be applied to other \u003ccode\u003e*Client\u003c/code\u003e classes like \u003ccode\u003eBigtableTableAdminClient\u003c/code\u003e and \u003ccode\u003eInstanceTableAdminClient\u003c/code\u003e.\u003c/p\u003e\n"]]],[],null,["Version 2.22.1keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/bigtable/latest/bigtable-auth-example)\n- [2.41.0](/cpp/docs/reference/bigtable/2.41.0/bigtable-auth-example)\n- [2.40.0](/cpp/docs/reference/bigtable/2.40.0/bigtable-auth-example)\n- [2.39.0](/cpp/docs/reference/bigtable/2.39.0/bigtable-auth-example)\n- [2.38.0](/cpp/docs/reference/bigtable/2.38.0/bigtable-auth-example)\n- [2.37.0](/cpp/docs/reference/bigtable/2.37.0/bigtable-auth-example)\n- [2.36.0](/cpp/docs/reference/bigtable/2.36.0/bigtable-auth-example)\n- [2.35.0](/cpp/docs/reference/bigtable/2.35.0/bigtable-auth-example)\n- [2.34.0](/cpp/docs/reference/bigtable/2.34.0/bigtable-auth-example)\n- [2.33.0](/cpp/docs/reference/bigtable/2.33.0/bigtable-auth-example)\n- [2.32.0](/cpp/docs/reference/bigtable/2.32.0/bigtable-auth-example)\n- [2.31.0](/cpp/docs/reference/bigtable/2.31.0/bigtable-auth-example)\n- [2.30.0](/cpp/docs/reference/bigtable/2.30.0/bigtable-auth-example)\n- [2.29.0](/cpp/docs/reference/bigtable/2.29.0/bigtable-auth-example)\n- [2.28.0](/cpp/docs/reference/bigtable/2.28.0/bigtable-auth-example)\n- [2.27.0](/cpp/docs/reference/bigtable/2.27.0/bigtable-auth-example)\n- [2.26.0](/cpp/docs/reference/bigtable/2.26.0/bigtable-auth-example)\n- [2.25.1](/cpp/docs/reference/bigtable/2.25.1/bigtable-auth-example)\n- [2.24.0](/cpp/docs/reference/bigtable/2.24.0/bigtable-auth-example)\n- [2.23.0](/cpp/docs/reference/bigtable/2.23.0/bigtable-auth-example)\n- [2.22.1](/cpp/docs/reference/bigtable/2.22.1/bigtable-auth-example)\n- [2.21.0](/cpp/docs/reference/bigtable/2.21.0/bigtable-auth-example)\n- [2.20.0](/cpp/docs/reference/bigtable/2.20.0/bigtable-auth-example)\n- [2.19.0](/cpp/docs/reference/bigtable/2.19.0/bigtable-auth-example)\n- [2.18.0](/cpp/docs/reference/bigtable/2.18.0/bigtable-auth-example)\n- [2.17.0](/cpp/docs/reference/bigtable/2.17.0/bigtable-auth-example)\n- [2.16.0](/cpp/docs/reference/bigtable/2.16.0/bigtable-auth-example)\n- [2.15.1](/cpp/docs/reference/bigtable/2.15.1/bigtable-auth-example)\n- [2.14.0](/cpp/docs/reference/bigtable/2.14.0/bigtable-auth-example)\n- [2.13.0](/cpp/docs/reference/bigtable/2.13.0/bigtable-auth-example)\n- [2.12.0](/cpp/docs/reference/bigtable/2.12.0/bigtable-auth-example)\n- [2.11.0](/cpp/docs/reference/bigtable/2.11.0/bigtable-auth-example) \n\nOverride the authentication configuration\n=========================================\n\nYou can override this default using [`google::cloud::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 namespace bigtable = ::google::cloud::bigtable;\n [](std::string const& project_id, std::string const& instance_id,\n std::string const& table_id, std::string const& keyfile) {\n auto is = std::ifstream(keyfile);\n is.exceptions(std::ios::badbit);\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 auto resource = bigtable::TableResource(project_id, instance_id, table_id);\n return bigtable::Table(bigtable::MakeDataConnection(options), resource);\n }\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\nChanging the default authentication configuration for other `*Client` classes is very similar, as shown in these examples:\n\n- [`BigtableTableAdminClient`](/cpp/docs/reference/bigtable/2.22.1/BigtableTableAdminClient-with-service-account-snippet)\n- [`InstanceTableAdminClient`](/cpp/docs/reference/bigtable/2.22.1/BigtableInstanceAdminClient-with-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."]]