7 simple steps to run your first Azure Queue program

7 simple steps to run your first Azure Queue program

Introduction

Azure queues help to communicate data between web role and worker role. Web roles are nothing but web application which can be accessed by the end browser. Worker roles are back ground processes which run in the azure system and they do not take direct request from the web.
So if we want to pass data to worker roles we need to use Queues. Queues are temporary storage which acts like a bridge between web role and worker role. So you can post data to web role , web role posts data to queues and worker role picks the data from queues to do further processing.
Please feel free to download my free 500 question and answer eBook which covers .NET , ASP.NET , SQL Server , WCF , WPF , WWF , Silver light , Azure @ http://tinyurl.com/4nvp9t .

What will we do in this article?

In this article we will create a simple application which will allow us to enter customer feedbacks. These customer feedback messages will go through a quality check whether the messages have any kind spam keywords. Currently we will only check for “XXX”.



In other words the above web role will submit the feedback message to queues, worker role will pick up the message, does a quality check and if the quality check passes it will add it to the Azure table. In case you are new to how to create an Azure table please read here http://computerauthor.blogspot.com/2010/01/9-simple-steps-to-run-your-first-azure.html

Step 1:- Ensure you have things at place
In case you are a complete fresher to Azure, please ensure you have all the pre-requisite at place. You can read the below article to get the basic prerequisite http://computerauthor.blogspot.com/2010/01/9-simple-steps-to-run-your-first-azure.html
Step 2:- Create a web role and worker project

The next step is to select the cloud service template, add the web role project and create your solution.


Step 3:- Configure service definition and configuration files.
The next step is to define table storage and queue storage location in the service definition and configuration. Just to revise service definition files help your define the configuration name while service configuration actually set the value.
Below is how the service definition file looks like , we need to the account name , shared key , queue storage and table storage end point. We need to define both these definition both for worker role as well as web role.
We are not sure if there is a way to avoid this redudancy. We googled and found that we indeed to define different definition even if the names are same , below is one of the links which talks about the same http://bstineman.spaces.live.com/Blog/cns!61AEA8168D26EA6B!291.entry

<?xml version="1.0" encoding="utf-8"?>
<ServiceDefinition name="QueueStorage" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition">
<WebRole name="WebRole1" enableNativeCodeExecution="false">
<InputEndpoints>
<!-- Must use port 80 for http and port 443 for https when running in the cloud -->
<InputEndpoint name="HttpIn" protocol="http" port="80" />
</InputEndpoints>
<ConfigurationSettings>
<Setting name="AccountName" />
<Setting name="AccountSharedKey" />
<Setting name="QueueStorageEndpoint" />
<Setting name="TableStorageEndpoint" />
</ConfigurationSettings>
</WebRole>
<WorkerRole name="WorkerRole1" enableNativeCodeExecution="false">
<ConfigurationSettings>
<Setting name="AccountName" />
<Setting name="AccountSharedKey" />
<Setting name="QueueStorageEndpoint" />
<Setting name="TableStorageEndpoint" />
</ConfigurationSettings>
</WorkerRole>
</ServiceDefinition>

Once you have defined the definitions its time to define the configuration values for this definitions.Below is the service
configuration file which has the values for all the 4 definitions defined in the definition file. You can see that the end point for both storage and queues are defined using a URL , in other words these storages are exposed through REST services.
Currently all the 4 configurations point to the local development storage , these values will change when you want to host online on the actual azure platform.

<?xml version="1.0"?>
<ServiceConfiguration serviceName="QueueStorage" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration">
<Role name="WebRole1">
<Instances count="1" />
<ConfigurationSettings>
<Setting name="AccountName" value="devstoreaccount1" />
<Setting name="AccountSharedKey"
value="Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==" />
<Setting name="QueueStorageEndpoint" value="http://127.0.0.1:10001" />
<Setting name="TableStorageEndpoint" value="http://127.0.0.1:10002" />
</ConfigurationSettings>
</Role>
<Role name="WorkerRole1">
<Instances count="1" />
<ConfigurationSettings>
<Setting name="AccountName" value="devstoreaccount1" />
<Setting name="AccountSharedKey"
value="Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==" />
<Setting name="QueueStorageEndpoint" value="http://127.0.0.1:10001" />
<Setting name="TableStorageEndpoint" value="http://127.0.0.1:10002" />
</ConfigurationSettings>
</Role>
</ServiceConfiguration>

Step 4:- Add CustomerInfo entity class

The next step is to create our entity class which has customer name and message. So below is a simple entity class called as ‘CustomerInfo’ which inherits from ‘TableStorageEntity’. This class has 2 properties ‘CustomerName’ and ‘Message’.

public class CustomerInfo :
Microsoft.Samples.ServiceHosting.StorageClient.TableStorageEntity
{
public CustomerInfo()
{
this.PartitionKey = "CustomerInfos";
this.RowKey = DateTime.Now.Ticks.ToString();
}
public string CustomerName { get; set; }
public string Message { get; set; }
}

Step 5:- Add CustomerInfoDataContext class

We need to create one more class i.e. the data context class. This class is responsible for adding the above defined customer entity class. So the first thing is inherit from the ‘TableStorageDataServiceContext’ class as shown in the below code snippet.

public class CustomerInfoDataContext : TableStorageDataServiceContext
{}

In the same class we creat a initializetable method which will create the table structure define by the ‘CustomerInfo’ class.
Below is the code snippet explanation with comments.

public void InitializeTable()
{
// Get access to the account of table storage end point
StorageAccountInfo accountInfo =StorageAccountInfo.GetAccountInfoFromConfiguration("TableStorageEndpoint",true);

// Create the table using the ‘TableStorage’ class. TableStorage.CreateTablesFromModel(typeof(CustomerInfoDataContext), accountInfo);
}

We also need to expose ‘IQueryable’ interface which exposes ‘CustomerInfo’ class which can be used by Azure system to create
azure table structure.

public IQueryable<CustomerInfo> CustomerInfos
{
get
{
return this.CreateQuery<CustomerInfo>("CustomerInfos");
}
}

We are also exposing a ‘AddCustomer’ method which takes the ‘CustomerInfo’ object , this object is then added to the Azure
table using the ‘AddObject’ method of the ‘TableStorageDataServiceContext’ and finally for committing the same to the table we call the ‘SaveChanges’ method.

public void AddCustomer(CustomerInfo _objCustomer)
{
this.AddObject("CustomerInfos", _objCustomer);
this.SaveChanges();
}

Once we add the customer entity in to the table we would like to display the same , so we have exposed a ‘GetCustomerInfo’
function which is type casted to list and this can be binded to the grid view.

public List<CustomerInfo> GetCustomerInfo()
{

return this.CustomerInfos.ToList();
}

Step 6:- Create web role to add customer messages

The next step is to create a web role project with a ASPX UI page as shown below. You can see that the UI has a gridview source which can be used to display messages and 2 text boxes for customer name
and feedback.


The submit messages button adds messages to the queue while the get old feedback messages displays the messages from the tables.
In order to add the customer and messages to the queue the first step is to get hold of the ‘StorageAccountInfo’ object using the configuration of the queues.

StorageAccountInfo accountQueueInfo = StorageAccountInfo.GetDefaultQueueStorageAccountFromConfiguration();

Use this account queue information to create the storage.

QueueStorage qs = QueueStorage.Create(accountQueueInfo);

Get the customer queue using the Queuestorage class.

MessageQueue queue = qs.GetQueue("customer");

Create the customer queue if it does not exist using the ‘DoesQueueExist’ method.

if (!queue.DoesQueueExist())
queue.CreateQueue();

Create the message object by concatentating both the text boxes and put the same in the queue.
Message msg = new Message(TextBox1.Text+"#"+TextBox3.Text);
queue.PutMessage(msg);We also have a second button on the web role screen to display the data added in the customer table. So below is the code which will help you display data from the azure table.Get hold of the ‘CustomerInfoDataContext’ class.
CustomerInfoDataContext
objCustomerDataContext = new CustomerInfoDataContext();
Use the ‘GetCustomerInfo’ function which was discussed in the previous steps to get a list of ‘CustomerInfo’ object.

List<CustomerInfo> _objCustomer = objCustomerDataContext.GetCustomerInfo();

Finnally bind the customer objects with the gridview.

if (_objCustomer.Count > 0)

{
GridView1.DataSource = _objCustomer;
GridView1.DataBind();
}

Step 7:- Create worker role to read the messages
In step 7 we have seen how the web role inserts data in to the queue. Now the queue is read by the worker role , the message is parsed and searched for ‘xxx’ , if its not found it will add the same to tables. So the first step is get hold of the queue object as shown in the below code snippet.

StorageAccountInfo accountQueueInfo = StorageAccountInfo.GetDefaultQueueStorageAccountFromConfiguration();
QueueStorage qs = QueueStorage.Create(accountQueueInfo);
MessageQueue queue = qs.GetQueue("customer");

In the worker there will be a infinite loop which will keep running and polling for messages using the queue objects which we just obtained from the above step.

while (true)
{
Message msg = queue.GetMessage();
if (msg != null)
{
// Parse XXX data here
}

}
In the while loop we get the message and checkfor ‘XXX” as shown in the below code snippet. If we do not find a ‘XXX’ we add
it to the table as entity using the data context object as shown in the below code snippet.



string message = msg.ContentAsString();
string name = message.Substring(0, message.IndexOf("#"));
string msgUser = message.Substring(message.IndexOf("#") + 1, message.Length - message.IndexOf("#") - 1);
if (!msgUser.Contains("xxx"))
{
CustomerInfo _obj = new CustomerInfo();
CustomerInfoDataContext objCustomerDataContext = new CustomerInfoDataContext();
_obj.CustomerName = name; _obj.Message = msgUser;
objCustomerDataContext.InitializeTable();
objCustomerDataContext.AddCustomer(_obj);
}

queue.DeleteMessage(msg);
Now we are all set to run the program. Just toensure that all the tables are created , right click on the visual studio
project and select ‘Create test storage tables’ as shown below.




Enjoy your hard work. If you now add ‘XXX’ in the feedback message its not added to the table and rejected by the worker role.
If you add a normal message its displayed on the grid view source of the webrole project.







Source code
You can get the source code of the above sample from here.

Simple 7 steps to run your first Azure Blob Program

Simple 7 steps to run your first Azure Blob
Program

Introduction


Step 1:- Ensure you have
things at place

Step 2:-
What will we do?

Step 3:-
Create a web role


Step 4:- Set the blob
connection string



Step 5:- Create the blob
on webrole onstart



Step 6:- Code your ASP.NET UI


Step 7:- Run the project and enjoy

Introduction

In this section we will create our first program using Azure blobs. This article
creates a simple web page where we upload image files which are stored in azure
blobs. We have also created a simple search text box which will help us to
search the image blobs with the image file name.

In case you are a complete newbie to azure you can download my two azure basic
videos which explain what azure is all about Azure Faq Part 1 :-
Video1 , Azuer Faq Part 2 :-
Video2.

Please feel free to download my free 500 question and answer eBook which covers
.NET , ASP.NET , SQL Server , WCF , WPF , WWF@
http://www.questpond.com/ .

Step 1:- Ensure you have
things at place

In case you are a complete fresher to Azure,
please ensure you have all the pre-requisite at place. You can read the below
article to get the basic prerequisite

http://computerauthor.blogspot.com/2010/01/simple-5-steps-to-run-your-first-azure.html .

Step 2:-
What will we do?

Azure Blobs help to store large items like
files, in other words its file storage system. In this article we will create a
simple program to upload image files in Azure blob system.

Step 3:-
Create a web role

The first step is to a create a web role
project. In case you are fresher in Azure, you can go through

http://computerauthor.blogspot.com/2010/01/simple-5-steps-to-run-your-first-azure.html to understand
how to create a web role project.
So let’s create a simple project with name ‘BlobStorage’. Once you have created
the project it creates two projects one is the cloud service project and the
other is the web role project. Cloud service project has all the necessary
configuration needed for your cloud service project while the web role project
is your asp.net project.

Step 4:- Set the blob
connection string

Now the next step is to define a blob
connection string in the service configuration file. So expand the ‘BlobStorage’
project, right click on roles and select properties.







Once you select properties, go to settings tab and add the blob connection
string as shown in the below figure. In the below figure we have added blob
connection string name as ‘BlobConnectionString’.





Click on the right hand eclipse and select ‘Use
development storage’. All the changes done using the setting UI will be
reflected in the ‘ServiceConfiguration’ file as shown above.

Step 5:- Create the blob
on webrole onstart

Now it’s time to start coding. Open the web
role project and open ‘WebRole.cs’ file.





Now let’s write a code on the ‘onstart’ event
to create the blob container.

public override bool OnStart()

{





}

Use the ‘CloudStorageAccount’ static class to
set the configuration environment.

public override bool OnStart()

{

// Set the configuration file

DiagnosticMonitor.Start("DiagnosticsConnectionString");

CloudStorageAccount.SetConfigurationSettingPublisher((configName, configSetter) =>

{

configSetter(RoleEnvironment.GetConfigurationSettingValue(configName));

});

....

....

....

....

}

The next step is to get a reference of the
cloudstorageaccount object using the blob connection string which was provided
when you setup your web role project.

// get the blob connection string

CloudStorageAccount objStorage = CloudStorageAccount.FromConfigurationSetting("BlobConnectionString");

Once we have access to the storage account
object, use the blob end point to create the blob client.

// get the client reference

CloudBlobClient objClient = new CloudBlobClient(objStorage.BlobEndpoint, objStorage.Credentials);

Give a nice name to the container and create
the container object using the client object which you have just created using
the blob end point. Call the ‘CreateIfnotExist’ method of the container to
ensure that you create the blob container only if it does not exist to avoid any
errors.

// Get the reference to container

CloudBlobContainer objContainer = objClient.GetContainerReference("mycontainer");



// Create the container if it does not exist

objContainer.CreateIfNotExist();

Step
6:- Code your ASP.NET UI

The final step is to create the ASPX page which
will help us upload image files in the blob container which we just created in
the ‘WebRole.cs’ file. You can see in t he below figure we have create a browse
button which help us upload image files and a search text box which will help us
search blob files.

So create the below defined ASPX UI.





In the above ASPX CS UI first get the reference
to the below specified name spaces.

using Microsoft.WindowsAzure;

using Microsoft.WindowsAzure.StorageClient;

In the file upload button we need to insert the
below code snippet to upload the file. So get access to the container object
‘MyContainer’ and call the ‘GetBlobReference’ function to get access to the
cloud blob object.

// Get the storage account reference

CloudStorageAccount objStorage = CloudStorageAccount.FromConfigurationSetting("BlobConnectionString");

// get the Client reference using storage blobend point

CloudBlobClient objClient = new CloudBlobClient(objStorage.BlobEndpoint, objStorage.Credentials);

// Get Container reference

CloudBlobContainer objContainer = objClient.GetContainerReference("mycontainer");

// Get blob reference

CloudBlob obj =objContainer.GetBlobReference(FileUpload1.FileName.ToString());

Set the meta data of the cloud object and open
a blob stream object to write the file. Do not forget to close the blob steam
object once you are done.

// Set meta values

obj.Metadata["MetaName"] = "meta";

// Open a stream using the cloud object

BlobStream blobstream = obj.OpenWrite();

// Write the stream to the blob database

blobstream.Write(FileUpload1.FileBytes, 0, FileUpload1.FileBytes.Count());

blobstream.Close();

Once we upload the file, we will browse through
the blob list to get the list of blobs present in the container.

// Browse through blob list from the container

IEnumerable<IListBlobItem> objBlobList = objContainer.ListBlobs();

foreach (IListBlobItem objItem in objBlobList)

{

Response.Write(objItem.Uri + "<br>");

}

In the same UI we have provided a search object
to search a blob. To search a blob first get access to the container object and
call the ‘GetBlobReference’ function with the blob name to get reference to the
cloud object.

// Get the blob reference using the blob name provided in the search

CloudBlob obj = objContainer.GetBlobReference(txtSearch.Text);

BlobStream blobstream = obj.OpenRead();

Read the blob stream using the blob steam
object and finally attach this stream with the Image object to display the same
in the HTTP response.

// Create the image object and display the same on the browser response

System.Drawing.Image objimg=null;

objimg = System.Drawing.Image.FromStream(blobstream,true);

Response.Clear();

Response.ContentType = "image/gif";

objimg.Save(Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);

Step 7:- Run the project and enjoy

Finally enjoy your first blob program. You can
see in the below figure we have uploaded some image files in the blob.





We can also search the blob using the search
blob text box and you should be able to get the below image display from the
blob database.