Unless otherwise configured, the client libraries use Application Default Credentials 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 The 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::memcache_v1::CloudMemcacheClient(
google::cloud::memcache_v1::MakeCloudMemcacheConnection(options));
}
[[["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 2025-08-14 UTC."],[[["\u003cp\u003eThis webpage provides documentation for various versions of the C++ Memcache client library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe default authentication for the client libraries uses Application Default Credentials, but it can be overridden when necessary.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication by utilizing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e and providing a service account key file, as demonstrated in the example.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example shows how to explicitly load a service account key file and use it for authentication with the Memcache client.\u003c/p\u003e\n"],["\u003cp\u003eFor detailed information about creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, refer to the "Authentication Components" documentation.\u003c/p\u003e\n"]]],[],null,[]]
