messengerapi/code/MessengerApi.Configuration/Sources/Environment/EnvironmentConfigurationSource.cs

namespace MessengerApi.Configuration.Sources.Environment
{
    public class EnvironmentConfigurationSource : IEnvironmentConfigurationSource
    {
        public bool HasKey(string key)
        {
            return !string.IsNullOrWhiteSpace(System.Environment.GetEnvironmentVariable(key));
        }

        public T GetValue<T>(string key)
        {
            if (typeof(T).Equals(typeof(Guid)))
            {
                var guid = Guid.Parse(System.Environment.GetEnvironmentVariable(key));
                return (T)Convert.ChangeType(guid, typeof(T));
            }

            return (T)Convert.ChangeType(System.Environment.GetEnvironmentVariable(key), typeof(T));
        }
    }
}