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Using the Windows Azure SDK for Node.js on Heroku

Getting the Windows Azure SDK for Noje.js running on Heroku wasn't as easy as we thought, in this article we're going to show you how we can workaround the Heroku limitation and how to create a simple application that leverages the SDK for listing blob containers.

The limitation

As you may know, to get a Node.js application running on Heroku you need to configure the application to use the Cedar stack as described here. One of the prerequisites is that your application must run on v0.4.7 but sadly the Windows Azure SDK for Noje.js npm package requires >= 0.6.4 as defined in its package.json file, so when Heroku tries to perform the deployment it fails because of this npm dependency.

We created an issue on the Github site azure-sdk-for-node and the team will be changing it soon apparentely. If that's the case, then go straight to the Creating the application section.

Workaround 1

Basically we created Windows Azure SDK for Noje.js fork, we tweaked the package.json file and use a tarball from GitHub as the npm package reference instead of using the official 0.6.5 package. Here are the steps:

NOTE: If you don't want to perform any other modification to the code, you can just use the tarball from my fork. If you want to use your fork replace jpgarcia by your Github's username.

DISCLAIMER: We didn't test all the library's functionality but it seems to be working fine running on v0.4.7.

Workaround 2

There is a Running Your Own Node.js Version on Heroku blog post that describes how to deploy a custom version of Node.js. We didn't use this approach but it should work.

Creating the application

We'll use the express npm package to create the application, so lets start.

  1. Create a new package.json file and configure the express, ejs and azure (using the tarball) as the project dependencies: 

    {
          "name": "heroku-azure-storage-sample" ,
          "version": "0.0.1" ,
          "dependencies": {
            "express": "2.5.2",
            "ejs": "0.6.1",
            "azure": "https://github.com/jpgarcia/azure-sdk-for-node/tarball/master"
          }
    }

  2. Create a web.js file with the following application logic to retrieve the containers for a given account:

    var express = require('express')
            , azure = require('azure');


    /*
     * Configuration
     * ---------------------------------------- */
    var app = express.createServer(express.logger());
    app    .register('html', require('ejs'));
    app    .set('view engine', 'html');


    /*
     * Routes
     * ---------------------------------------- */
    app    .get('/', function (req, res) {
            var blobClient = azure.createBlobService(process.env['WAZ_STORAGE_ACCOUNT_NAME'], process.env['WAZ_STORAGE_ACCESS_KEY'])
                                  .withFilter(new azure.ExponentialRetryPolicyFilter());
        blobClient    .listContainers({}, function(err, result) {
            res    .render('index', { layout: false, containers: result });
            });         
    });


    /*
     * Bootstrap
     * ---------------------------------------- */
    var port = process.env.PORT || 3000;


    app    .listen(port, function () {
        console    .log("Listening on " + port);
    });    

  3. Configure your account WAZ_STORAGE_ACCOUNT_NAME and WAZ_STORAGE_ACCOUNT_ACCESSS_KEY environment variables:

    • If you are running Node.js on Windows, from the command line:

      SET WAZ_STORAGE_ACCOUNT_NAME=accountname
      SET WAZ_STORAGE_ACCESS_KEY      =accountkey

    • If you are running Node.js on MacOS, from a console:

      export WAZ_STORAGE_ACCOUNT_NAME=accountname
      export WAZ_STORAGE_ACCESS_KEY=accountkey

  4. Create a new views folder with an index.html file inside with to display the list of containers retrieved from Azure:

    <!doctype html>
    <html lang="en">
            <head>
              <title>WAZ Storage Sample</title>
            </head>
            <body>
                <h1>Containers</h1>
                <ul>
                <% for(var i=0;i<containers.length;i++) { %>
                    <li><%= containers[i].name %></li>
                <% } %>
                </ul>
            </body>
    </html>

  5. Intall the npm dependencies, from the command line:

    npm install

  6. Run application locally:

    node web.js

  7. Browse the application:

    http://localhost:3000

Deploying the Applicattion to Heroku

To deploy the application you must have installed the Heroku Toolbelt.

  1. Create a Procfile in your project's root folder to declare the commands to run when the application is deployed to Heroku. In this case the Procfile will have only one row for running the website:

    web: node web.js

  2. Create a .gitignore file in your project's root file with the following content:

    node_modules

  3. Initialize a new git repository:

    git init
    git add     .
    git commit     -m "init"

  4. Create a new application on Heroku specifying the cedar stack:

    heroku create your-application-name --stack cedar

  5. Set the environment variables with your Azure account name and key:

    heroku config:add WAZ_STORAGE_ACCOUNT_NAME=accountname
    heroku config    :add WAZ_STORAGE_ACCESS_KEY=accountkey

  6. Deploy your application

    git push heroku master

  7. That's it, now you can navigate your application at:

    http://your-application-name.herokuapp.com
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