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::logging_v2::LoggingServiceV2Client(
google::cloud::logging_v2::MakeLoggingServiceV2Connection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 version available is 2.37.0-rc, with previous versions listed down to 2.11.0 for reference.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries use Application Default Credentials for authentication with Google Cloud Services, but this can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eYou can override the default credentials by providing the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e, demonstrated using a service account key file example.\u003c/p\u003e\n"],["\u003cp\u003eThe example shows how to explicitly load a service account key file to override the default authentication, which is a simple, easy to understand way of doing it, but is not the only way.\u003c/p\u003e\n"],["\u003cp\u003eFor more details on managing service account keys, consult the Best practices guide and for more information on creating credentials objects, check the Authentication Components section.\u003c/p\u003e\n"]]],[],null,[]]
