class which lets you configure log4net using blob storage, and monitors the changes of config blob

Log4NetBlobConfigure

//To use this class call Log4NetBlobConfigure.ConfigureAndWatch(); in your Application.OnStart()

    public class Log4NetBlobConfigure
    {
        private static string _lastEtag;
        private static DateTimeOffset? _lastModified;
        private const string ContainerName = "config";
        private const string BlobUrl = "log4net.config";

        private static readonly object LockInstance = new object();
        private static readonly ILog log = LogManager.GetLogger(typeof(Log4NetBlobConfigure));
        public static void ConfigureAndWatch(int refreshPeriodInSeconds = 60)
        {

            lock (LockInstance)
            {
                LockedConfigureAndWatch(refreshPeriodInSeconds);
            }

        }

        private static void LockedConfigureAndWatch(int refreshPeriodInSeconds)
        {
            if (!Connections.IsStoreConnectionstringDefined)
            {
                
                SysLogger.Fatal("could not configure as store connectino string is not defined ");

                throw new ApplicationException("connection string for storage not defined");
            }

			SysLogger.Info("Lock And configure called");
            log.Info("Lock And configure called");

            if (RefreshTimer != null)
                RefreshTimer.Dispose();

            _repository = LogManager.GetRepository(Assembly.GetCallingAssembly());

            Configure();

            RefreshTimer = new Timer { Interval = refreshPeriodInSeconds * 1000 };
            RefreshTimer.Elapsed += CheckConfig;
            RefreshTimer.Start();
        }

        private static ILoggerRepository _repository;
        protected static CloudStorageAccount StorageAccount { get; set; }

        private static void CheckConfig(object sender, EventArgs e)
        {
            var context = CloudStorageAccount.Parse(Connections.AbaloStoreConnectionstring);
            var blobClient = context.CreateCloudBlobClient();

            CloudBlobContainer container = blobClient.GetContainerReference(ContainerName);
            CloudBlockBlob blob = container.GetBlockBlobReference(BlobUrl);
            blob.FetchAttributes();
            if ((_lastModified != null && _lastModified != blob.Properties.LastModified) || (_lastEtag != null && _lastEtag != blob.Properties.ETag))
            {
                SysLogger.Info("Reconfiguring using blob store");
                log.Info("Lock And configure called");
                Configure();
            }
        }

        private static void Configure()
        {
            try
            {
                DoConfigure();
            }
            catch (Exception exception)
            {
                log.Error("error in configure", exception);
				SysLogger.Fatal("error reconfiguring", exception);
                throw;
            }
            
        }

        private static void DoConfigure()
        {
            var context = CloudStorageAccount.Parse(Connections.AbaloStoreConnectionstring);

            var blobClient = context.CreateCloudBlobClient();

            CloudBlobContainer container = blobClient.GetContainerReference(ContainerName);
            CloudBlockBlob blob = container.GetBlockBlobReference(BlobUrl);
            blob.FetchAttributes();

            _lastEtag = blob.Properties.ETag;
            _lastModified = blob.Properties.LastModified;

            var stream = new MemoryStream();
            blob.DownloadToStream(stream);
            stream.Position = 0;

			var result = log4net.Config.XmlConfigurator.Configure(_repository, stream);

			foreach (object o in result)
			{
				var loglog = o as LogLog;
				if (loglog == null)
				{
					SysLogger.Fatal("wierdness in logger" + o);
				}
				else
				{
					SysLogger.Fatal("error configuring logger" + loglog.Message, loglog.Exception);
				}
			}

            stream.Dispose();
        }

        protected static Timer RefreshTimer { get; set; }
    }