Presenters, L Putting together a cloud based web application that allows end users to upload, encode, manage and distribute video media files is not a difficult task these days. Especially with the number of related frameworks and services available, ready to be used or consumed. The situation gets more complex when the expected traffic is in the millions-of-users range, globally distributed, and requiring detailed monitoring for usage. Using this scenario, in this session you will learn how to use the recently updated Datastax C# Cassandra driver, how to deploy a multi-datacenter Cassandra cluster using the Microsoft Azure platform that can be accessed from different programming languages, and how to leverage existing cloud services to perform some of the tasks associated with this use case.

1. Highly Scalable Web Application in the
Cloud with Cassandra, C# and Azure
Luke Tillman (@LukeTillman)
Language Evangelist, DataStax
Jeremiah Talkar (@JST2Cents)
Azure Evangelist, Microsoft

2. KillrVideo Intro and Demo
www.killrvideo.com

3. .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");

4. .NET and Cassandra
• Executing CQL
var
statement
=
new
SimpleStatement("SELECT
*
FROM
users
WHERE
userid
=
?");
statement
=
statement.Bind(145);
RowSet
rows
=
await
session.ExecuteAsync(statement);
• Sync and Async API available

5. .NET and Cassandra
• PROTIP: Prepared Statements are your friend
PreparedStatement
prepared
=
session.Prepare("SELECT
*
FROM
users
WHERE
userid
=
?");
• Prepare once (server roundtrip), Bind and Execute many
BoundStatement
boundStatement
=
prepared.Bind(145);
RowSet
rows
=
await
session.ExecuteAsync(boundStatement);
• Remember: Save and reuse your Prepared Statement instances

6. .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");
}

7. .NET and Cassandra
• Mapping results to DTOs: if you like using CQL, try CqlPoco package
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);
• Note: This package may be pulled into the official driver soon.

8. .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();

9. 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

10. 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)

11. Microsoft Azure

12. 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.

13. 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