A file containing the Longview API key. To get this, look in Longview settings which are found at https://manager.linode.com/longview/.<a href="/nixpkgs/option/services.longview.apiKeyFile"><a href="/nixpkgs/option/apiKeyFile" rel="nofollow">apiKeyFile</a></a> takes precedence over <a href="/nixpkgs/option/services.longview.apiKey"><a href="/nixpkgs/option/apiKey" rel="nofollow">apiKey</a></a>.