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::ConfigServiceV2Client(
google::cloud::logging_v2::MakeConfigServiceV2Connection(options));
}
Follow these links to find examples for other *Client classes:
[[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 of the logging documentation is 2.37.0-rc, with previous versions available from 2.36.0 down to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eBy default, client libraries authenticate using Application Default Credentials, but you can override this with the UnifiedCredentialsOption.\u003c/p\u003e\n"],["\u003cp\u003eOverriding the default authentication can be done by loading a service account key file, as demonstrated in the provided example.\u003c/p\u003e\n"],["\u003cp\u003eExamples of how to override authentication credentials are provided for \u003ccode\u003elogging_v2::ConfigServiceV2Client\u003c/code\u003e, \u003ccode\u003elogging_v2::LoggingServiceV2Client\u003c/code\u003e, and \u003ccode\u003elogging_v2::MetricsServiceV2Client\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eFor more in depth details, refer to the "Best practices for managing service account keys" guide, and the Authentication Components documentation.\u003c/p\u003e\n"]]],[],null,[]]
