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Building Cloud Applications for Windows Azure

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PCQ Bureau
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Windows Azure platform is created to help developers write, distribute and

manage Web application and Web services on the Internet. Azure provides

on-demand computation and storage services that allows Web applications to scale

them on Internet simply by changing the configuration parameters. Azure is an

operating system for the cloud, using which developers can host and manage their

applications as services on Windows Azure platform.

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Windows Azure supports both Microsoft and non-Microsoft languages and

environments  -developers can use Ruby, PHP, and Python to develop Azure

Services. Azure supports a seamless development experience and is well

integrated with Visual Studio.

Direct Hit!

Applies To: .NET Developers



USP: Build apps for cloud Primary
Link:

www.microsoft.com




Search Engine Keywords: Windows Azure

Setting up  development environment in Visual Studio



You can download the Azure SDK and Azure tools and use them in Visual

Studio. In order to create an Azure application, the pre-requisite operating

systems are Windows Vista with SP1, Windows Server 2008 or Windows 7. You would

also need .NET framework 3.5 with SP1 installed. Additionally, the development

machine should be configured with IIS 7 (with ASP.NET and WCF HTTP Activation).

Also it requires Microsoft SQL Server (or express) 2005 or 2008.

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To develop Windows Azure application you would need either of the following:

MS Visual Studio 2008 SP1, MS Visual Studio 2010 Beta 1 or MS Visual Web

Developer 2008 Express Edition with SP1.

Once you have the required IDE, you will need Azure SDK and Azure tools for

Visual Studio to  start developing your first Azure application.

Clicking on 'File->New Project' in Visual Studio will

display Project Template for creating Cloud Application.
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Windows Azure Tools for MS Visual Studio extends Visual Studio 2008 and

Visual Studio 2010 Beta 1 to enable creation, building, debugging, and running

of applications on Azure. To obtain this SDK and the tools, go to www.microsoft

.com/download and search for 'Windows azure tools'. The file to be downloaded is

VSCloudService.exe that will install both Azure SDK as well as Azure tools in

your Visual Studio Shell. Once you have installed the tools, you will see that a

new project type has been added to your Visual Studio. See the image below.

A Cloud solution consists of two projects. Here,

'forPCQuest' and 'WebRole1' are two projects added to Visual Studio Solution

file.
Clicking on 'File->New Project' in Visual Studio will

display Project Template for creating Cloud Application.

Creating Cloud application in Visual Studio



Creating a new Cloud Service project in Visual Studio will create two

projects for you in the solution (see second image). If you look into the

Solution Explorer, the first project is (forPCQuest) where  application

configuration setting for Cloud is stored. Other project is a simple ASP.NET web

application (WebRole1). Service Definition (.cscdef) file in the first project

is used to provision Web application 'as a Service' for cloud. To achieve this,

the XML tag used is:

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Once the Web Application is added as a service as mentioned

above, we can set configuration settings for our Web Application in Service

Configuration file (.cscfg). If you open Service Configuration file, you will

see the following code:

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xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration">

 

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This file describes what setting your web application will

use when deployed on the cloud. Checkout the instances count setting, for

example, that allows you to configure the scalability requirements. This is

interesting to see how you can dynamically increase the load capacity of your

web application on-demand. This is one of the promises that Windows Azure

delivers.

Now, let's open our Web application (WebRole1) and make

some changes in it. If we open Defualt.aspx file and add the line:



Welcome PC Quest Reader

In order to build our application, we can right click and

select Build or directly select Publish option that will first build the

application and then attempt to publish it (see the above image). If we select

the publish option, it creates a 'publish' directory somewhere at the same place

where the project source files are stored and creates two files. These files are

1. Service package file which has our Web Application in Cloud deployable

format, and 2. Cloud Service Configuration file which consists of configuration

settings for Cloud that our Web Application will use. Also, the Visual studio

will automatically open browser and point to a URL https://windows. azure.com/Cloud/

Provisioning/Default.aspx where you can provision your small Cloud application

that you have just built.

 A cloud application can be hosted on

windows.azure.com. The first step is to define a URI on Internet so that

your cloud application gets a Unique Internet address.

You may like to test your application locally on your

machine before you deploy it to http://windows.azure.com. In order to do that,

just select the Cloud project and hit 'Ctrl + F5'.  You will notice two small

icons on the right side of your status bar — these are 'Development Fabric'and

'Development Storage'. These are nothing but a local implement of Windows Azure

with all the necessary services to deploy and test a Cloud application locally.

Preparing for deployment at windows.azure.com



Microsoft is hosting Windows Azure as a free service for people to host

their Cloud applications at http://windows. azure.com . It requires you to first

register on the site and thereafter a token for Windows Azure trial is sent to

you in your email. Once you receive this token, you can create a blank Azure

project on windows. azure. com. After a blank project is created, you need to

add a 'Hosting Service' to your Azure project (see image 4)

 A cloud application is first deployed to 'Staging'

environment, tested, and then moved on to 'Production' environment.

While creating a 'Hosted Service' you will be required to

have a unique name by which your service will be identified on Internet. The

full name of the service will be http://yourUniqueName. cloudapp.net

Uploading your Package and Cloud configuration file to

Windows Azure



In the Hosted Service you just created, now you can deploy your files that

you created using Visual Studio. You have to first deploy them on Staging before

you can promote them to production.

Click on the Deploy button and  upload the files from

'update' directory.

 Type the URL of your Cloud Application in any browser

and hit Enter. You will be able to see your first Cloud application running.

First your application is deployed to staging environment

where you can do testing and verification. In staging environment, it allocates

a temporary URL on web to work with. After you are satisfied with your

application behavior in Staging, you can promote it to production. While you

deploy your application to Staging or Production, please wait for few minutes

before it shows a green 'started' icon in front of web role. Only after the

'started' status appears, you will be able to launch your application from the

'Web Site URL' links

You have successfully created and deployed your first Cloud

application on Widows Azure. You can visit the URL: http://pcquest. cloudapp.net/

and see the same application deployed there. (See the last image)

Vivek Goyal, Developer Technology Specialist, Microsoft India

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