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"]],[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThe latest release candidate version is 2.37.0-rc, and numerous previous versions of the memcache authentication documentation are also available, ranging down to version 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries primarily utilize Application Default Credentials for Google Cloud Services authentication, although this can be overridden when necessary.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default authentication method by providing a \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, such as loading a service account key file explicitly using the provided example code.\u003c/p\u003e\n"],["\u003cp\u003eThe provided example is straightforward for understanding purposes, but best practices for managing service account keys should be consulted for optimal security.\u003c/p\u003e\n"],["\u003cp\u003eMore information on creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects can be found in the "Authentication Components" documentation.\u003c/p\u003e\n"]]],[],null,[]]
