Highly Scalable Web Application in the

Cloud with Cassandra, C# and Azure

Luke Tillman (@LukeTillman)

Language Evangelist, DataStax

Jeremiah Talkar (@JST2Cents)

Azure Evangelist, Microsoft

KillrVideo Intro and Demo www.killrvideo.com

.NET and Cassandra • Open Source (on GitHub), available via NuGet

• Bootstrap using the Builder and then reuse the ISession object

Cluster cluster = Cluster.Builder() .AddContactPoint("127.0.0.1") .Build(); ISession session = cluster.Connect("killrvideo");

.NET and Cassandra • Executing CQL

• Sync and Async API available

var statement = new SimpleStatement("SELECT * FROM users WHERE userid = ?"); statement = statement.Bind(145); RowSet rows = await session.ExecuteAsync(statement);

.NET and Cassandra • PROTIP: Prepared Statements are your friend

• Prepare once (server roundtrip), Bind and Execute many

• Remember: Save and reuse your Prepared Statement instances

PreparedStatement prepared = session.Prepare("SELECT * FROM users WHERE userid = ?");

BoundStatement boundStatement = prepared.Bind(145); RowSet rows = await session.ExecuteAsync(boundStatement);

.NET and Cassandra • Getting values from a RowSet is easy

• Rowset is a collection of Row (IEnumerable<Row>)

RowSet rows = await _session.ExecuteAsync(boundStatement); foreach (Row row in rows) { var videoId = row.GetValue<Guid>("videoid"); var addedDate = row.GetValue<DateTimeOffset>("added_date"); var name = row.GetValue<string>("name"); }

.NET and Cassandra • Mapping results to DTOs: if you like using CQL, try CqlPoco package

• Note: This package may be pulled into the official driver soon.

public class User { public Guid UserId { get; set; } public string Name { get; set; } } // Get a user by id from Cassandra or null if not found var user = client.SingleOrDefault<User>( "SELECT userid, name FROM users WHERE userid = ?", someUserId);

.NET and Cassandra • Mapping results to DTOs: if you like LINQ, use built-in LINQ provider

[Table("users")] public class User { [Column("userid"), PartitionKey] public Guid UserId { get; set; } [Column("name")] public string Name { get; set; } } var user = session.GetTable<User>() .SingleOrDefault(u => u.UserId == someUserId) .Execute();

Remember… • Prepared Statements are a great performance optimization but

remember to Prepare once, Bind and Execute many

• Take advantage of the async API to give your web server a break or run

queries in parallel

• Don’t write boilerplate mapping code—use LINQ or CqlPoco

KillrVideo on Azure

Cassandra Cluster (DSE)

App data storage (video

metadata, comments, users,

ratings, etc.)

Azure Media Services

Uploaded video encoding,

thumbnail generation, Video

access URI generation

Azure Storage

Queues – notifications on

encoding job progress

Blob – uploaded video storage

OpsCenter

provisioning,

monitoring,

management

KillrVideo Web App C# MVC Web Application, Azure Web Role

Serves up UI, JSON Endpoints

KillrVideo Upload Worker C#, Azure Worker Role

Monitors encoding job events, publishes completed

uploads

Web UI HTML5 / JavaScript (KnockoutJS, jQuery, Bootstrap, etc)

Microsoft Azure

Why Azure? • Enterprise Business

• Hybrid story, not Cloud only, via single cloud platform model

• Broadest Reach via Azure regions footprint, global hosting partners and

on premises

• Azure Active Directory

• Richness of finished services O365, Azure Mobile Services, Azure

Notification Services, Azure API Management, Azure Media Services,

Device Hub, etc.

Next Steps • Get the code and schema on GitHub

https://github.com/luketillman/killrvideo-csharp

• Use the live demo hosted in Azure

http://www.killrvideo.com

• Sign up for free Azure trial subscription

http://azure.microsoft.com