Build and deploy a Node.js application to a Windows Azure Cloud Service

On completing this guide, you will have a simple Node.js application running in a Windows Azure Cloud Service. Cloud Services are the building blocks of scalable cloud applications in Windows Azure. They allow the separation and independent management and scale-out of front-end and back-end components of your application. Cloud Services provide a robust dedicated virtual machine for hosting each role reliably.

For more information on Cloud Services, and how they compare to Windows Azure Web Sites and Virtual machines, see Windows Azure Web Sites, Cloud Services, and VMs: When to use which?

Looking to build a simple web site?

If your scenario involves just a simple web site front-end, consider using a lightweight Windows Azure Web Site. You can easily upgrade to a Cloud Service as your web site grows and your requirements change.

By following this tutorial, you will build a simple web application hosted inside a web role. You will use the compute emulator to test your application locally and then you will deploy it using PowerShell command-line tools.

A screenshot of the completed application is below:

A browser window displaying Hello World

Creating a New Node Application

Perform the following tasks to create a new Windows Azure Cloud Service project, along with basic Node.js scaffolding:

From the Start Menu or Start Screen, search for Windows Azure PowerShell. Finally, right-click Windows Azure PowerShell and select Run As Administrator.
Something missing?
To successfully complete this section, you must have a working installation of Node.js and the Windows Azure SDK for Node.js for your platform.
- Install the Windows Azure SDK for Node.js: Windows installer | Mac installer | Linux download
- If you are using Mac or Linux, install Node.js from http://nodejs.org. The Windows installer already includes Node.js.
Create a new node directory on your C drive, and change to the c:\node directory:

$A command prompt displaying the commands 'mkdir c:\node' and 'cd node'.$
Enter the following cmdlet to create a new solution:
```
PS C:\node> New-AzureServiceProject helloworld
```
You will see the following response:

The New-AzureServiceProject cmdlet generates a basic structure for creating a new Windows Azure Node application which will be published to a Cloud Service. It contains configuration files necessary for publishing to Windows Azure. The cmdlet also changes your working directory to the directory for the service.

The files created by the New-AzureServiceProject cmdlet are:
- ServiceConfiguration.Cloud.cscfg, ServiceConfiguration.Local.cscfg and ServiceDefinition.csdef are Windows Azure-specific files necessary for publishing your application.
  
  For more information about these files, see Overview of Creating a Hosted Service for Windows Azure.
- deploymentSettings.json stores local settings that are used by the Windows Azure PowerShell deployment cmdlets.
Enter the following command to add a new web role using the Add-AzureNodeWebRole cmdlet:
```
PS C:\node\helloworld> Add-AzureNodeWebRole
```
You will see the following response:

The Add-AzureNodeWebRole cmdlet creates a new directory for your application and generates scaffolding for a basic Node.js application. It also modifies the ServiceConfiguration.Cloud.csfg, ServiceConfiguration.Local.csfg, and ServiceDefinition.csdef files created in the previous step to add configuration entries for the new role.

Note
By default if you do not provide a role name, one will be created for you. You can provide a name as the first parameter to Add-AzureNodeWebRole. For example, Add-AzureNodeWebRole MyRole
Use the following commands to navigate to the WebRole1 directory, and then open the the server.js file in notepad.
```
PS C:\\node\\helloworld> cd WebRole1
PS C:\node\helloworld\WebRole1> notepad server.js
```
The server.js file was created by the Add-AzureNodeWebRole cmdlet, and contains the following starter code. This code is similar to the “Hello World” sample on the nodejs.org web site, except:
- The port has been changed to allow the application to find the correct port assigned to it by the cloud environment.
- Console logging has been removed.

Running Your Application Locally in the Emulator

One of the tools installed by the Windows Azure SDK is the Windows Azure compute emulator, which allows you to test your application locally. The compute emulator simulates the environment your application will run in when it is deployed to the cloud. Perform the following steps to test the application in the emulator.

Close Notepad and switch back to the Windows PowerShell window. Enter the following cmdlet to run your service in the emulator:
```
PS C:\node\helloworld\WebRole1> Start-AzureEmulator -Launch
```
The –Launch parameter specifies that the tools should automatically open a browser window and display the application once it is running in the emulator. A browser opens and displays “Hello World,” as shown in the screenshot below. This indicates that the service is running in the compute emulator and is working correctly.
To stop the compute emulator, use the Stop-AzureEmulator command:
```
PS C:\node\helloworld\WebRole1> Stop-AzureEmulator
```

Deploying the Application to Windows Azure

Note

To complete this tutorial, you need a Windows Azure account. You can create a free trial account and enable preview features in just a couple of minutes. For details, see Windows Azure Free Trial.

Downloading the Windows Azure Publishing Settings

In order to deploy your application to Windows Azure, you must first download the publishing settings for your Windows Azure subscription. The following steps guide you through this process:

From the Windows PowerShell window, launch the download page by running the following cmdlet:
```
PS C:\node\helloworld\WebRole1> Get-AzurePublishSettingsFile
```
This will use your browser to navigate to the publish settings download page. You may be prompted to log in with a Microsoft Account. If so, use the account associated with your Windows Azure subscription.

Save the downloaded profile to a file location you can easily access.
In the Windows Azure PowerShell window, use the following cmdlet to configure the Windows PowerShell for Node.js cmdlets to use the Windows Azure publishing profile you downloaded:
```
PS C:\node\helloworld\WebRole1> Import-AzurePublishSettingsFile [path to file]
```
Note
After importing the publish settings, consider deleting the downloaded .publishSettings file as it contains information that can be used by others to access your account.

Publishing the Application

Publish the application using the Publish-AzureServiceProject cmdlet, as shown below.
```
PS C:\node\helloworld\WebRole1> Publish-AzureServiceProject –ServiceName NodeHelloWorld –Location "East US” -Launch
```
- The servicename parameter specifies the name used for this deployment. This must be a unique name otherwise the publish process will fail.
- The location parameter specifies the datacenter that the application will be hosted in. To see a list of available datacenters, use the Get-AzureLocation cmdlet.
- The launch parameter will launch your browser and navigate to the hosted service after deployment has completed.
After publishing succeeds, you will see a response similar to the following:

The Publish-AzureServiceProject cmdlet performs the following steps:
1. Creates a package that will be deployed to Windows Azure. The package contains all the files in your node.js application folder.
2. Creates a new storage account if one does not exist. The Windows Azure storage account is used to store the application package during deployment. You can safely delete the storage account after deployment is done.
3. Creates a new cloud service if one does not already exist. A cloud service is the container in which your application is hosted when it is deployed to Windows Azure. For more information, see Overview of Creating a Hosted Service for Windows Azure.
4. Publishes the deployment package to Windows Azure.
Note
It can take 5–7 minutes for the application to deploy and become available when first published.

Once the deployment has completed, a browser window will open and navigate to the cloud service.

Your application is now running on Windows Azure!

Stopping and Deleting Your Application

After deploying your application, you may want to disable it so you can avoid extra costs. Windows Azure bills web role instances per hour of server time consumed. Server time is consumed once your application is deployed, even if the instances are not running and are in the stopped state.

In the Windows PowerShell window, stop the service deployment created in the previous section with the following cmdlet:
```
PS C:\node\helloworld\WebRole1> Stop-AzureService
```
Stopping the service may take several minutes. When the service is stopped, you receive a message indicating that it has stopped.
To delete the service, call the following cmdlet:
```
PS C:\node\helloworld\WebRole1> Remove-AzureService
```
When prompted, enter Y to delete the service.

Deleting the service may take several minutes. After the service has been deleted you receive a message indicating that the service was deleted.

Note

Deleting the service does not delete the storage account that was created when the service was initially published, and you will continue to be billed for storage used. For more information on deleting a storage account, see How to Delete a Storage Account from a Windows Azure Subscription.