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::redis_v1::CloudRedisClient(
google::cloud::redis_v1::MakeCloudRedisConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis document provides information on how to override the default authentication credentials used by client libraries to authenticate with Google Cloud Services.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version available is \u003ccode\u003e2.37.0-rc\u003c/code\u003e, with a range of other versions listed down to \u003ccode\u003e2.11.0\u003c/code\u003e, providing historical reference to how the override authentication works across different versions.\u003c/p\u003e\n"],["\u003cp\u003eOverriding authentication can be accomplished using \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, as demonstrated by an example which uses a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe example given is relatively easy to understand, but it is suggested that you consult the "Best practices for managing service account keys" for more information.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on factory functions to create \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, refer to the Authentication Components section.\u003c/p\u003e\n"]]],[],null,[]]
