Varnish e caching di applicazioni Rails

1. Varnish e caching di
applicazioni Rails
RubyDay 2011
Antonio Carpentieri

2. Disclaimer

3. l’applicazione

4. All’inizio andava tutto
bene

5. Poi è arrivato il momento
di mettere online
store.inter.it

6. Che si fa?

8. Reverse Proxy
“Varnish is a reverse Web accelerator designed for content-heavy
dynamic web sites. In contrast to other HTTP accelerators, many
of which began life as client-side proxies or origin servers,
Varnish was designed from the ground up as an accelerator for
incoming traffic.”

9. Quali vantaggi otteniamo?

10. Come si configura?

11. Come si configura?
• NON con un file in cui abiliti e disabiliti opzioni

12. Come si configura?
• NON con un file in cui abiliti e disabiliti opzioni
• Varnish Configuration Language (VCL)

13. Come si configura?
• NON con un file in cui abiliti e disabiliti opzioni
• Varnish Configuration Language (VCL)
• il VCL un DSL che viene compilato in codice C

14. Come si configura?
• NON con un file in cui abiliti e disabiliti opzioni
• Varnish Configuration Language (VCL)
• il VCL un DSL che viene compilato in codice C
• Espone gli hookpoint per gestire il cliclo di vita della
richiesta

15. Come si configura?
• NON con un file in cui abiliti e disabiliti opzioni
• Varnish Configuration Language (VCL)
• il VCL un DSL che viene compilato in codice C
• Espone gli hookpoint per gestire il cliclo di vita della
richiesta
• Può essere caricato senza fermare il servizio

16. Come si configura?
• NON con un file in cui abiliti e disabiliti opzioni
• Varnish Configuration Language (VCL)
• il VCL un DSL che viene compilato in codice C
• Espone gli hookpoint per gestire il cliclo di vita della
richiesta
• Può essere caricato senza fermare il servizio
• Si può switchare a caldo da una configurazione ad un’altra

17. Gli hook points
• vcl_recv Arriva la richiesta, qui decidi cosa farne
• vcl_fetch E’ stata recuparata la risorsa dal backend,
la puoi modificare prima di mandarla al client
• vcl_hash Calcola l’hash key per la ricerca, di default
è solo l’URL completa
Gli altri hooks:
vcl_deliver, vcl_miss, vcl_hit, vcl_error, vcl_discard, vcl_timeout,
vcl_pipe, vcl_pass

18. Varnish non “casha” niente che
sia “privato” o che abbia un
cookie...

19. e Rails ci mette del suo
per non farsi cachare

20. Cookie di sessione

21. Middleware
http://www.coffeepowered.net/2011/01/29/rails-varnish-cookie-sessions-and-csrf-tokens/

22. Middleware

23. cache-control private

24. helper method

25. helper method in
action

26. Risultato

27. Vogliamo parlare dei
tracking cookies?

28. Filtriamoli

29. Invalidare la cache

30. PURGE

31. PURGE
varnishadm -T 1.2.3.4:6082 purge.url ‘url_da_invalidare’

32. PURGE
varnishadm -T 1.2.3.4:6082 purge.url ‘url_da_invalidare’

33. Usando gli sweepers
# Gemfile
gem 'schoefmax-klarlack', :require => ‘klarlack’
# environment.rb
VARNISH = Varnish::Client.new(‘1.2.3.4:6082’)
class ProductSweeper < ActionController::Caching::Sweeper
observe Product # This sweeper is going to keep an eye on the Product model
include ActionController::UrlWriter
# If our sweeper detects that a Product was created call this
def after_create(product)
expire_cache_for(product)
end
# If our sweeper detects that a Product was updated call this
def after_update(product)
expire_cache_for(product)
end
# If our sweeper detects that a Product was deleted call this
def after_destroy(product)
expire_cache_for(product)
end
private
def expire_cache_for(product)
VARNISH.purge :url, product_path(product)
end
end

34. The “Vary” Pitfalls

35. User agents
User-Agent: TwengaBot-2.0 (http://www.twenga.com/bot.html)
User-Agent: Mozilla/5.0 (compatible; Yahoo! Slurp; http://help.yahoo.com/help/us/ysearch/slurp)
User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1
User-Agent: Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NE
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.24 (KHTML, like Gecko) C
User-Agent: Mozilla/5.0 (Windows NT 6.0) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91
User-Agent: Mozilla/5.0 (Windows NT 6.0; rv:2.0.1) Gecko/20100101 Firefox/4.0.1
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9.1.8) Gecko/20100202 Firefox/3.5.
User-Agent: Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)
User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/534.24 (KHTML, like Gecko) Chrome/11.0.696.77
User-Agent: Opera/9.80 (Windows NT 6.1; U; ja) Presto/2.8.131 Version/11.11
User-Agent: Googlebot-Image/1.0
User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10_5_8; it-it) AppleWebKit/533.21.1 (KHTML, lik
User-Agent:YottaaMonitor
User-Agent: Mozilla/5.0 (compatible; FatBot 2.0; http://www.thefind.com/crawler)
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_7; en-us) AppleWebKit/533.21.1 (KHTML, l
User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_7; ar) AppleWebKit/533.21.1 (KHTML, like
User-Agent: Mozilla/5.0 (compatible; YandexBot/3.0; +http://yandex.com/bots)
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91
User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.4; en-US; rv:1.9.2.17) Gecko/20110420 Firefo
User-Agent: Mozilla/5.0 (iPad; U; CPU OS 4_3_3 like Mac OS X; it-it) AppleWebKit/533.17.9 (KHTML, l
User-Agent: ELB-HealthChecker/1.0

36. Accept-languages

37. Accept-languages
Accept-Language: it

38. Accept-languages
Accept-Language: it
Accept-Language: it-IT

39. Accept-languages
Accept-Language: it
Accept-Language: it-IT
Accept-Language: it-it,it;q=0.8,en-us;q=0.5

40. Accept-languages
Accept-Language: it
Accept-Language: it-IT
Accept-Language: it-it,it;q=0.8,en-us;q=0.5
Accept-Language: it, en-us;q=0.8, en;q=0.7

41. Accept-languages
Accept-Language: it
Accept-Language: it-IT
Accept-Language: it-it,it;q=0.8,en-us;q=0.5
Accept-Language: it, en-us;q=0.8, en;q=0.7
Accept-Language: it, en-us;q=0.8, en;q=0.3

42. Accept-languages
https://github.com/cosimo/varnish-accept-language/

43. Accept-encoding

44. Accept-encoding
Accept-Encoding:gzip

45. Accept-encoding
Accept-Encoding:gzip
Accept-Encoding:gzip,deflate

46. Accept-encoding
Accept-Encoding:gzip
Accept-Encoding:gzip,deflate
Accept-Encoding:deflate,gzip

47. Accept-encoding
Accept-Encoding:gzip
Accept-Encoding:gzip,deflate
Accept-Encoding:deflate,gzip
Accept-Encoding:deflate, gzip

48. Accept-encoding
Accept-Encoding:gzip
Accept-Encoding:gzip,deflate
Accept-Encoding:deflate,gzip
Accept-Encoding:deflate, gzip
Accept-Encoding:gzip,deflate,sdch

49. Accept-encoding

50. Quali tools offre?

51. Quali tools offre?
•varnishtop

52. Quali tools offre?
•varnishtop
• varnishtop -i RxHeader -I ^User-Agent

53. Quali tools offre?
•varnishtop
• varnishtop -i RxHeader -I ^User-Agent
• varnishtop -i RxUrl

54. Quali tools offre?
•varnishtop
• varnishtop -i RxHeader -I ^User-Agent
• varnishtop -i RxUrl
• varnishtop -i RxHeader -I ^Referer

55. Quali tools offre?
•varnishtop
• varnishtop -i RxHeader -I ^User-Agent
• varnishtop -i RxUrl
• varnishtop -i RxHeader -I ^Referer
•varnishadm

56. Quali tools offre?
•varnishtop
• varnishtop -i RxHeader -I ^User-Agent
• varnishtop -i RxUrl
• varnishtop -i RxHeader -I ^Referer
•varnishadm
• vcl.load newconf /etc/conf2011.vcl

57. Quali tools offre?
•varnishtop
• varnishtop -i RxHeader -I ^User-Agent
• varnishtop -i RxUrl
• varnishtop -i RxHeader -I ^Referer
•varnishadm
• vcl.load newconf /etc/conf2011.vcl
• purge.url “^/stylesheets/”

58. Quali tools offre?
•varnishtop
• varnishtop -i RxHeader -I ^User-Agent
• varnishtop -i RxUrl
• varnishtop -i RxHeader -I ^Referer
•varnishadm
• vcl.load newconf /etc/conf2011.vcl
• purge.url “^/stylesheets/”
•varnishstat

59. Quali tools offre?
•varnishtop
• varnishtop -i RxHeader -I ^User-Agent
• varnishtop -i RxUrl
• varnishtop -i RxHeader -I ^Referer
•varnishadm
• vcl.load newconf /etc/conf2011.vcl
• purge.url “^/stylesheets/”
•varnishstat
•varnishhist

60. Dove siamo arrivati?

61. VARNISH 3.0
Key Features
• Compression support including ESI
• Plugin support in Varnish with VMODs
• Much improved tools and performance
Other Features
• Enhanced ESI support including stiching together compressed ESI fragments.
• Saint and Grace mode.
• DNS, Random, Hashing and Client IP based Directors.
• A much improved VCL.
• Preliminary support for Streaming support, both on miss and on pass.

62. Grazie per l’attenzione!
antonio.carpentieri@xpeppers.com
@acarpe
http://acarpe.wordpress.com