Azure Caching – Windows Azure SDK 2.0 - Azure Cloud & AI Domain Blog

Caching is one of the ways to achieve performance gains by serving request from a temporary location instead of calling backend resources for consequential requests. It is especially critical when considering most of the response times –throughput – take place during backend processes. In this post, I will explain how-to caching for cloud services with demonstration of a sample application.

Base Solution

I will be using the solution that I have used for the previous post as base for this exercise. The demonstration will include very simple case – caching the to-do list retrieved from Azure SQL database and responding all the list queries from there.

Steps

Step 1: Enable Cache

Right click on the role then select Properties

Select Caching from left menu

Check ‘Enable Caching’

Set Cache (depending)

Update storage account credentials (depending)

Step 2: Add reference to Azure Caching assembly

Right click on References Select Manage NuGet Packages
Search Azure Caching Click Install
Accept License terms
Close

Step 3: Implementing Caching

Update task controller utilizing Windows Azure Caching

   1: using System.Collections.Generic;

   2: using System.Diagnostics;

   3: using System.Linq;

   4: using System.Web.Mvc;

   5: using Microsoft.ApplicationServer.Caching;

   6: using ToDoData.Models;

7:

   8: namespace ToDoListWeb2.Controllers

   9: {

  10:     //[Authorize]

  11:     //[InitializeSimpleMembership]

  12:     public class TaskController : Controller

  13:     {

  14:         private const string CacheKey = "CachedTasks";

  15:         readonly DataCache _dataCache = new DataCache("default");

16:

  17:         //

  18:         // GET: /Home/

19:

  20:         public ActionResult Index()

  21:         {

  22:             return View(GetDataList());

  23:             //Util.TestTrace2();

  24:             //using (var context = new ToDoContext())

  25:             //    return View(context.ToDoItems.ToList());

  26:         }

27:

  28:         private List<ToDoItem> GetDataList()

  29:         {

  30:             if (_dataCache.Get(CacheKey) == null)

  31:             {

  32:                 Trace.TraceInformation("Cache with key '{0}' getting filled.", CacheKey);

  33:                 using (var context = new ToDoContext())

  34:                 {

  35:                     _dataCache.Add(CacheKey, context.ToDoItems.ToList());

  36:                 }

  37:             }

  38:             else

  39:                 Trace.TraceInformation("Serving the request from the Cache with key '{0}'.", CacheKey);

40:

  41:             return (List<ToDoItem>)_dataCache[CacheKey];

  42:         }

43:

  44:         //

  45:         // GET: /Home/Details/5

46:

  47:         public ActionResult Details(int id = 0)

  48:         {

  49:             using (var context = new ToDoContext())

  50:                 return View(context.ToDoItems.Find(id));

  51:         }

  52:     }

  53: }

Deployment Preparation

Before deployment we need to modify these (at least)

Modify instance count to 2+.
Update Microsoft.WindowsAzure.Plugins.Caching.ConfigStoreConnectionString key with the storage (blob, table) account you have
Make sure Diagnostics level is set to Information in order to see the tracing outputs written above
Update identifier attribute of autoDiscover tag with the name of the role you set caching. That would be “ToDoListWeb2” in my case.

   1: <dataCacheClients>

   2:   <dataCacheClient name="default">

   3:     <autoDiscover isEnabled="true" identifier="ToDoListWeb2" />

   4:     <!--<localCache isEnabled="true" sync="TimeoutBased" objectCount="100000" ttlValue="300" />-->

   5:   </dataCacheClient>

   6: </dataCacheClients>

The Result

As you can see, from the image below, first the cache is filled with data (1st request), then cache data used (consequential requests) directly.