During the amazing Umbraco Code Garden 2014 I presented a session titled 'Supercharge your Umbraco'. The session was all about caching with Umbraco and how in today's demanding web environment using these caching techniques can really help scale your application. The talk covers: 1. Macro Caching 2. Cached Partials 3. MVC Output Caching 4. MVC Donut Caching 5. Varnish Watch the talk back on the Umbraco stream http://stream.umbraco.org/video/9949630/supercharge-your-umbraco The example code I used during the presentation is available at the link below, it has all the handlers for purging the donut cache and for managing varnish. https://bitbucket.org/chrisgaskell/umbraco-caches

1. Supercharge your Umbraco
The need for speed

2. Chris Gaskell
@CGaskell
chris@detangled-digital.com

3. The Web is a Demanding Place

4. The Need for Speed

5. In computing a cache is a component that
transparently stores data so that future
requests for that data can be served faster.
The data that is stored within a cache may be
values that have been computed earlier or
duplicates of original values that are stored
elsewhere.
http://en.wikipedia.org/wiki/Cache_(computing)

6. Who Caches Already?

7. Umbraco's Cache is Always Running

8. Need More?
Umbraco
• Macro Caching
• Partial View Caching
.NET
• Output caching
• Donut caching
Infrastructure
• Varnish

9. Good Old Fashioned Optimisation
• JS & CSS minification & combination
• Image resizing
• Sprite sheets
• Client side caching
• GZIP

12. Macro Caching

13. Macro Caching
The original way to reuse blocks of functionality.
How to:
1. Define macro in back office
2. Add cache policy
3. Call macro from within view

14. Macro Caching Demo

15. Macro Caching
The Good
• Quick and easy to setup with instant results
• No .NET
• Easy to retro fit or fine tune on an existing install
• Cache clears on CMS publish
• Support for querystring parameters so long as they’re passed to the macro as parameters
• @Umbraco.RenderMacro("pageList", new { addSleep = "[@addsleep]"
The Bad
• Difficult to turn off in dev (Macro cache disabler package doesn’t look to be compatible
with 6+)
• With MVC logic is moved into the view as there’s no chance to hijack the route

16. Cached Partials

17. Cached Partials
You don't normally need to cache the output of Partial views but there are
times when this is necessary. Just like with macro caching you can cache the
output of partial views.
This is done simply by using an HtmlHelper extension method:
@Html.CachedPartial("MyPartialName", new MyModel(), 3600)
The above will cache the output of your partial view for one hour (3600
seconds)
http://our.umbraco.org/documentation/Reference/Mvc/partial-views

18. Cached Partials Demo

19. Cached Partials
The Good
• Quick and easy to setup with instant results
• Easy to retro fit or fine tune on an existing MVC codebase
• As the cache duration is passed this could be taken from a configuration setting
and set to easily in dev to 0 secs
• Cache clears on CMS publish
The Bad
• MVC logic is moved into the view as there’s no chance to hijack the route
• If your view data changes the same cached output will be returned.
Please be aware: if you have a different model or view data for any page request,
the result will be the cached result of the first execution

20. Output Caching

21. Output Caching
Output caching is a full page cache.
Output caching is part of the .NET framework and can be easily used
with MVC or web forms applications.
In MVC output caching is implemented using an action filter attribute
which can be applied to controller actions.

22. Output Cache Demo

23. Output Caching
The Good
• Available ‘out of the box’ with ASP.NET – there’s nothing to install
• Easy and quick to implement
• Fast and robust
• Easy to share common cache ‘profiles’ across the app from config
The Bad
• Difficult to clear on a publish
• The entire page is cached making personalisation and dynamic content difficult to
manage
• Requires good management in development to ensure developers aren’t seeing
cached content

24. Donut Caching

25. Donut Caching
Donut caching is one form of output caching that is conspicuously absent
from ASP.NET MVC and is greatly missed by many developers.
To implement donut caching the concept is fairly simple:
1. Cache the page output and return it from the cache on subsequent
requests
2. Identify the areas that you do not want to cache (the donut holes). These
areas are marked so that when the page is retrieved from cache these
areas are replaced with non-cached versions before returning the page

27. Donut Cache Demo

28. Donut Caching
The Good
• Gives the huge benefit of having portions of the page render for each
request while the surrounding mark-up comes from cache
• Installs quickly (via nuget is best)
• Easy to add into a well architected MVC solution
• Has a cache manager allowing easy coupling to publishing for purging the
cache
The Bad
• Requires good management in development to ensure developers aren’t
seeing cached content
• Does need some extra code to ensure the cache is purged on publish

29. But what if you need to go even
faster?

30. Varnish

31. Story Time

32. Dresses
Give me
dresses
Here’s
some dress
data
I’ll make it
look nice
Oooo
some dresses

33. Hats
Has this
already been
requested?
No
Hats please
Here’s
some dataMake it
look nice
I’ll store this
for the next
request
Oooo
Hats!

34. Hats
Has this
already been
requested?
Yes
Oooo
Hats!
Zzzzzz
Zzzzzz

35. Varnish Cache is a web application accelerator also known as a caching
reverse HTTP proxy
You install it in front of any server that speaks HTTP and configure it to
cache the contents
Varnish Cache is really, really fast. It typically speeds up delivery with a
factor of 300 - 1000x, depending on your architecture

36. @bsdphk we have a new record on web
infrastructure reduction: From 46 to 5
servers!! @varnishcache rocks!

37. €0.00

38. Infrastructure
RAM is what counts to allow the cache to scale. How much RAM
depends on your requirements.
• With varnish you configure the size of the cache
• Varnish also needs memory to do other things, so you'll see a fixed
couple of hundred extra megs.
• Varnish has a overhead of about 1k per object.
• Each thread (e.g., worker) will allocate its own memory, including a
stack. This memory usage will scale and contract as load spawns and
reaps threads.

39. Installation on Ubuntu
To use the varnish-cache.org repository, do the following:
1. curl http://repo.varnish-cache.org/debian/GPG-key.txt | sudo apt-
key add -
2. echo "deb http://repo.varnish-cache.org/ubuntu/ precise varnish-
3.0" | sudo tee -a /etc/apt/sources.list
3. sudo apt-get update
4. sudo apt-get install varnish

40. Installing on Windows?
“Remember that Varnish on Cygwin Windows is not recommended
for productions sites and it is only a proof-of-concept that can be
used to test application on Windows or for checking you VCL while in
that platform.”
https://www.varnish-cache.org/trac/wiki/VarnishOnCygwinWindows

41. Inside Varnish
When a web page or content is requested:
Check if the content is cacheable
If content is in cache
Return cached content
Else
Fetch content from Web server
Put the content in the cache
Return content
Else
Return by fetching from Web server

42. /etc/varnish/default.vcl

43. /etc/varnish/default.vcl
backend default {
.host = "umbracocaches.detangled-digital.com";
.port = "80";
}
sub vcl_recv {
set req.http.host = "umbracocaches.detangled-digital.com";
if (req.request == "GET" || req.request == "HEAD") {
return (lookup);
}
}
sub vcl_fetch {
# Remove Expires from backend, it's not long enough
unset beresp.http.expires;
# Set the clients TTL on this object
set beresp.http.cache-control = "max-age=900";

44. Varnish Demo

45. Grab your internet enabled device and
navigate to
http://bit.ly/1ozG165

46. Refresh the page and watch the timestamp
jump
http://bit.ly/1ozG165

47. Now have a look at the same page through
Varnish
http://bit.ly/1hjTPCK

48. All well and good, but what happens when I
publish content changes?

49. Cache Invalidation
• purge; removes all variants of an object from cache, freeing up
memory
• ban(); can be used to invalidate objects based on regular expressions,
but does not necessarily free up memory any time soon

50. /etc/varnish/default.vcl
backend default {
.host = "umbracocaches.detangled-digital.com";
.port = "80";
}
sub vcl_recv {
set req.http.host = "umbracocaches.detangled-digital.com";
if (req.request == "PURGE") {
return (lookup);
}
if (req.request == "GET" || req.request == "HEAD") {
return (lookup);
}
}
sub vcl_hit {
if (req.request == "PURGE") {
purge;

51. Purge on Publish
public class VarnishCachePurger : ApplicationEventHandler
{
private const string VarnishHost = "varnish.umbracocaches.detangled-digital.com";
protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication,
ApplicationContext applicationContext)
{
ContentService.Published += ContentServiceOnPublished;
ContentService.Deleted += ContentServiceOnDeleted;
ContentService.Moved += ContentServiceOnMoved;
}
private static void ContentServiceOnPublished(IPublishingStrategy sender, PublishEventArgs<IContent>
{
foreach (IContent item in e.PublishedEntities)
{
PurgeUrl(library.NiceUrl(item.Id));
}
}
private static void ContentServiceOnDeleted(IContentService sender, DeleteEventArgs<IContent> e)

52. Real Life Umbraco VCLs

53. /etc/varnish/default.vcl
backend default {
.host = "detangled-digital.com";
.probe = {
.timeout = 10s;
.interval = 20s;
.threshold = 2; }
}
# --------------------------------------------------------------------------------
# vcl_recv
# --------------------------------------------------------------------------------
sub vcl_recv {
# Set the port and host header on requests so that the correct back-end website is targeted
set req.http.Host = regsub(req.http.Host, ".varnish.dev$", ".dd.dev"); # Dev
set req.http.Host = regsub(req.http.Host, ":d+$", ""); # Staging
# Handle ban request
if (req.request == "BAN") {
if (!req.http.X-Ban-Key ~ "6e035c2b-6109-4fed-9b44-7fec75cfe3f8") {
error 405 "Not allowed";

54. Load Testing

55. Load Testing the Demo
Without Varnish With Varnish

56. What Else
• Load Balancing
• Can be configured as round-robin or random
• Probing
• This accesses the heath of the application servers and can take servers in and out of
the balancing pool
• Serving stale cache
• Should the application server go down Varnish can serve a ‘stale’ cache
• A Large set of monitoring and logging commands
• https://www.varnish-cache.org/docs/4.0/reference/index.html

57. Thanks to Mike Gregson
@mpgregson

58. Get the sample code
https://bitbucket.org/chrisgaskell/umbraco-caches
See it integrated into a V7 example
https://bitbucket.org/chrisgaskell/gemscafe
Chris Gaskell
@CGaskell
chris@detangled-digital.com