Question

我有一个辅助角色，所以当我部署它时，它只运行一次，然后什么都不做，这是我的代码，我该如何解决这个问题？我只改变了这个地方，功能OnStart和OnStop是默认的。

public class WorkerRole : RoleEntryPoint
{
    private readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
    private readonly ManualResetEvent runCompleteEvent = new ManualResetEvent(false);

    public override void Run()
    {
        Thread.Sleep(10000);
        Trace.TraceInformation("WorkerRole is running");

        while(true)
        {
            try
            {
                this.RunAsync(this.cancellationTokenSource.Token).Wait();
            }
            finally
            {
                this.runCompleteEvent.Set();
            }
        }
    }

    public override bool OnStart()
    {
        ServicePointManager.DefaultConnectionLimit = 12;
        bool result = base.OnStart();
        Trace.TraceInformation("WorkerRole has been started");
        return result;
    }

    public override void OnStop()
    {
        Trace.TraceInformation("WorkerRole is stopping");

        this.cancellationTokenSource.Cancel();
        this.runCompleteEvent.WaitOne();

        base.OnStop();

        Trace.TraceInformation("WorkerRole2 has stopped");
    }

    public byte[] imageToByteArray(System.Drawing.Image imageIn)
    {
        MemoryStream ms = new MemoryStream();
        imageIn.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
        return ms.ToArray();
    }


    private CloudBlobContainer GetImageBlobContainer()
    {
        var storageAccount = CloudStorageAccount.Parse("myconnectionstring");
        var blobClient = storageAccount.CreateCloudBlobClient();
        var container = blobClient.GetContainerReference("cadblob");
        container.CreateIfNotExists();

        container.SetPermissions(
            new BlobContainerPermissions
            {
                PublicAccess = BlobContainerPublicAccessType.Blob
            });
        return container;
    }

    public static Image ScaleImage(Image image, int maxWidth, int maxHeight)
    {
        var ratioX = (double)maxWidth / image.Width;
        var ratioY = (double)maxHeight / image.Height;
        var ratio = Math.Min(ratioX, ratioY);

        var newWidth = (int)(image.Width * ratio);
        var newHeight = (int)(image.Height * ratio);

        var newImage = new Bitmap(newWidth, newHeight);
        Graphics.FromImage(newImage).DrawImage(image, 0, 0, newWidth, newHeight);
        return newImage;
    }

    private async Task RunAsync(CancellationToken cancellationToken)
    {
        CloudStorageAccount storageAccount = CloudStorageAccount.Parse("Myconnectionstring");            
        CloudQueueClient queueClient = storageAccount.CreateCloudQueueClient();           
        CloudQueue queue = queueClient.GetQueueReference("cadqueue");            
        CloudQueueMessage retrievedMessage = queue.GetMessage();

        if (retrievedMessage.AsString != null || retrievedMessage.AsString != "")
        {
            string[] msg = retrievedMessage.AsString.Split(' ');

            CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
            CloudTable table = tableClient.GetTableReference("cadtable");

            TableOperation retrieveOperation = TableOperation.Retrieve<ImageEntity>("Images", msg[0]);
            TableResult retrievedResult = table.Execute(retrieveOperation);
            var container = GetImageBlobContainer();
            msg[2] = "mini_" + msg[2];
            CloudBlockBlob blockBlob = container.GetBlockBlobReference(msg[2]);
            blockBlob.Properties.ContentType = msg[1];

            Image img;
            var webClient = new WebClient();
            byte[] imgBytes = webClient.DownloadData(((ImageEntity)retrievedResult.Result).Full_img);
            using (var ms = new MemoryStream(imgBytes))
            {
                img = Image.FromStream(ms);
            }
            Image thumb = ScaleImage(img, 220, 160);
            var fileBytes = imageToByteArray(thumb);
            await blockBlob.UploadFromByteArrayAsync(fileBytes, 0, fileBytes.Length);

            ImageEntity ent = (ImageEntity)retrievedResult.Result;
            if (ent != null)
            {
                ent.Mini_img = "https://cadwebstorage.blob.core.windows.net/cadblob/" + msg[2];
                TableOperation insertOrReplaceOperation = TableOperation.InsertOrReplace(ent);
                table.Execute(insertOrReplaceOperation);
            }
            else
            {
                Console.WriteLine("Entity could not be retrived.");
            }

            queue.DeleteMessage(retrievedMessage);
        }


        while (!cancellationToken.IsCancellationRequested)
        {
            Trace.TraceInformation("Working");
            await Task.Delay(10000);
        }
    }

}

Answer 1

由于此循环，图像缩放代码仅工作一次的原因

 while (!cancellationToken.IsCancellationRequested)
        {
            Trace.TraceInformation("Working");
            await Task.Delay(10000);
        }

在private async Task RunAsync(CancellationToken cancellationToken)内。除非您停止工作器实例，否则永远不会终止。要修复它，您可以将图像处理代码放在循环中，如下所示

private async Task RunAsync(CancellationToken cancellationToken)
        {
            while (!cancellationToken.IsCancellationRequested)
            {
                ScaleImage();
                await Task.Delay(10000);
            }
        }

        private void ScaleImage()
        {
            Trace.TraceInformation("Scaling Image");
            CloudStorageAccount storageAccount = CloudStorageAccount.Parse("Myconnectionstring");
            CloudQueueClient queueClient = storageAccount.CreateCloudQueueClient();
            CloudQueue queue = queueClient.GetQueueReference("cadqueue");
            CloudQueueMessage retrievedMessage = queue.GetMessage();

            if (retrievedMessage.AsString != null || retrievedMessage.AsString != "")
            {
                string[] msg = retrievedMessage.AsString.Split(' ');

                CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
                CloudTable table = tableClient.GetTableReference("cadtable");

                TableOperation retrieveOperation = TableOperation.Retrieve<ImageEntity>("Images", msg[0]);
                TableResult retrievedResult = table.Execute(retrieveOperation);
                var container = GetImageBlobContainer();
                msg[2] = "mini_" + msg[2];
                CloudBlockBlob blockBlob = container.GetBlockBlobReference(msg[2]);
                blockBlob.Properties.ContentType = msg[1];

                Image img;
                var webClient = new WebClient();
                byte[] imgBytes = webClient.DownloadData(((ImageEntity)retrievedResult.Result).Full_img);
                using (var ms = new MemoryStream(imgBytes))
                {
                    img = Image.FromStream(ms);
                }
                Image thumb = ScaleImage(img, 220, 160);
                var fileBytes = imageToByteArray(thumb);
                await blockBlob.UploadFromByteArrayAsync(fileBytes, 0, fileBytes.Length);

                ImageEntity ent = (ImageEntity)retrievedResult.Result;
                if (ent != null)
                {
                    ent.Mini_img = "https://cadwebstorage.blob.core.windows.net/cadblob/" + msg[2];
                    TableOperation insertOrReplaceOperation = TableOperation.InsertOrReplace(ent);
                    table.Execute(insertOrReplaceOperation);
                }
                else
                {
                    Console.WriteLine("Entity could not be retrived.");
                }

                queue.DeleteMessage(retrievedMessage);
            }

        }

并且您不需要while(true)中的循环Run()。 Run()可以像这样简单

public override void Run()
        {
            try
            {
                RunAsync(cancellationTokenSource.Token).Wait();
            }
            finally
            {
                runCompleteEvent.Set();
            }
        }

Azure Worker Role刚刚开始工作

1 个答案: