A sample video sharing application showing how to use Apache Cassandra with .NET via DataStax .NET Driver in the Microsoft Azure cloud. The application is based on a sample schema (that has since been modified) for a video sharing site that Patrick McFadin has been using to demonstrate data modeling techniques with Apache Cassandra.

If you'd like a more in-depth introduction to the application, including a tour of the code structure, architecture, and some of the motivations, check out my blog post KillrVideo: Cassandra, C# and Azure. I also have a ongoing series of blog posts on KillrVideo which can be found under the killrvideo tag on my blog.

A live demo of KillrVideo running on Cassandra in Azure is available at www.killrvideo.com.

Once you've cloned the repository, you'll need to do a few things to get up and running locally.

You'll need a running Cassandra cluster. For local development, that cluster can just be a single node running on your local machine. You can get a copy from Planet Cassandra (grab the DataStax Community edition). If you're on Windows, the MSI installer from Planet Cassandra makes installing a node on your local development machine easy. If you'd like more details on installing and developing with Cassandra on Windows, check out my blog post aptly titled Developing with Cassandra on Windows.

The Microsoft Azure SDK will allow you to run Azure web/worker roles via an emulator on your local machine. If you don't already have it, you'll need to install it.

KillrVideo makes use of a number of Microsoft Azure services. As a result, you'll need to provision the appropriate resources in the Azure Management Portal under your account. If you don't already have an Azure account, you can get a free trial of Azure from Microsoft. From the management portal, you'll need to create:

• An Azure Storage account to use for Azure Media Services. This is used to store uploaded videos from the app.
• An Azure Media Services account. The portal will ask you to select an Azure Storage account when you create the Media Services account (select the one you just created previously). This is used to process and encode uploaded videos for playback.
• An Azure Service Bus namespace. This is used for communication between services (via events) in the application.

KillrVideo allows adding videos to the site from sources other than uploads (for example, YouTube). As a result, you'll need to create a YouTube API key. Follow the instructions from Google for creating a project and adding a key in the Google Developers console.

Note: You don't need an OAuth 2.0 key, just a regular API key. You'll want to create a Browser Key when prompted by the console.

Run the schema.cql script in the data/ folder against your Cassandra cluster to create the appropriate schema. For example (via CQL Shell):

cqlsh -f schema.cql

If you'd like a GUI for exploring Cassandra (and running the CQL script to create the schema), check out the free Dev Center tool for developers.

You'll need to configure your local copy of KillrVideo with the correct connection strings and API keys that you created. Here are the steps:

1. Under the /src/KillrVideo.Azure folder, find the ServiceConfiguration.Local.Transform.cscfg.template configuration transform file. Make a copy and rename it to ServiceConfiguration.Local.Transform.cscfg (i.e. remove the .template file extension).
2. Edit the ServiceConfiguration.Local.Transform.cscfg transformation file you just created and fill in the values for your local environment. You'll need to provide:

• CassandraClusterLocation: the IP/DNS for your Cassandra cluster (for example, 127.0.0.1).
• AzureMediaServicesAccountName: the account name for your Azure Media Services account.
• AzureMediaServicesAccountKey: the secret key for your Azure Media Services account
• AzureStorageConnectionString: the connection string for the Storage account that's linked to your Azure Media Services account.
• AzureServiceBusConnectionString: the connection string for the Service Bus namespace that you created.
• YouTubeApiKey: the YouTube API key that you created.

Open KillrVideo.sln in Visual Studio. Right-click on the KillrVideo.Azure project and set it as the startup project. Press F5 to launch the KillrVideo.Azure project with a debugger attached. It should launch the Azure Emulator and IIS Express by default. The web site will run on 127.0.0.1 by default.

KillrVideo contains a SampleData service that will periodically add sample YouTube videos, users, comments, etc. to the site on a schedule. The first time you run the application, some of that data should be added (you will probably need to refresh the home page of the web application after about 30 seconds to see the initial sample videos). When running locally, you can also manually trigger adding sample data to the site using the Add Sample Data link in the footer of the site.

When uploading videos to share, the client-side JavaScript uploads directly to Azure Storage (bypassing the KillrVideo web app) so as not to put additional strain on the web server just for video uploads. It does this by taking advantage of CORS-enabled uploads for Azure Media Services. For this to work, you'll need to add a CORS rule to your Azure Storage account. Unfortunately, you can't manage these rules via the Azure Management Portal UI, however someone else has built a simple UI for managing these rules.

1. Grab the Azure CORS Rule Manager web app from GitHub.
2. Open it in Visual Studio and run it (no configuration is needed to launch the app).
3. Enter the credentials for the Azure Storage account linked to your Azure Media Services account.
4. Add a CORS rule (modify these to fit your local settings):
   • Allowed origins: http://127.0.0.1, http://youralias.local
   • Allowed methods: Put
   • Allowed headers: content-type, accept, x-ms-*
   • Exposed headers: x-ms-*
   • Max age (seconds): 86400

This project will continue to evolve along with Cassandra and you can expect that as Cassandra and the DataStax driver add new features, this sample application will try and provide examples of those. I'll gladly accept any pull requests for bug fixes, new features, etc. and if you have a request for an example that you don't see in the code currently, send me a message @LukeTillman on Twitter or open an issue here on GitHub.

Copyright 2014 Luke Tillman

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.