It is believed that the Symfony framework is quite heavy and it can be difficult to develop a website that will be able to work under the high load. It is true, but does this mean that it is impossible to implement a dynamic caching and to update only a small part of entire page as data is updated? This talk will give your an answer to that. It is Varnish, ESI-blocks and load balancing. With hundreds of thousands of unique visitors and million hits a day, we continue to use Symfony, and do not see any problems.

1. Handling 10k Requests/second
With Symfony and Varnish
Alexander Lisachenko

2. About me:
lisachenko
lisachenko

3. ‣ Head of Software Architecture
at Alpari (RU) Forex Broker
About me:
lisachenko
lisachenko

4. ‣ Head of Software Architecture
at Alpari (RU) Forex Broker
‣ Have worked with computers
since 7 years old
About me:
lisachenko
lisachenko

5. ‣ Head of Software Architecture
at Alpari (RU) Forex Broker
‣ Have worked with computers
since 7 years old
‣ Clean code advocate, guru in
enterprise architecture
About me:
lisachenko
lisachenko

6. Author of the Go! AOP
Framework
‣ http://go.aopphp.com

7. Agenda

8. Agenda
‣ We review briefly the process of typical
Symfony site growing

9. Agenda
‣ We review briefly the process of typical
Symfony site growing
‣ What is Varnish and why it’s so popular

10. Agenda
‣ We review briefly the process of typical
Symfony site growing
‣ What is Varnish and why it’s so popular
‣ How to prepare your Symfony site for
Varnish?

11. Agenda
‣ We review briefly the process of typical
Symfony site growing
‣ What is Varnish and why it’s so popular
‣ How to prepare your Symfony site for
Varnish?
‣ VCL tricks to easily handle 10K
requests/second with Symfony

12. Site Growing

13. First deploy to the production

14. First deploy to the production

15. First deploy to the production
1-30 RPS

16. First marketing campaign

17. First marketing campaign

18. First marketing campaign

19. First marketing campaign
30-50 RPS

20. Configuring cacheing layer

21. Configuring cacheing layer
OpCache

22. Configuring cacheing layer
OpCache MemCache
60-250 RPS

23. Preparing several backends
OpCache MemCache

24. Preparing several backends
OpCache MemCache
250-1k RPS

25. Preparing several backends
OpCache MemCache
250-1k RPS

28. Reverse proxy caching
OpCache MemCache

29. Reverse proxy caching
OpCache MemCache
Varnish
1k-20k RPS

31. Varnish is an HTTP accelerator designed
for content-heavy dynamic web sites as
well as heavily consumed APIs.

32. Websites using Varnish
Source: https://trends.builtwith.com

33. Websites using Varnish
Source: https://trends.builtwith.com

34. Simple workflow:

35. Simple workflow:
GET /some-web-page

36. Simple workflow:
GET /some-web-page
X-Cache: MISS

37. Simple workflow:
GET /some-web-page
X-Cache: MISS
GET /some-web-page

38. Simple workflow:
GET /some-web-page
X-Cache: MISS
GET /some-web-page

39. Simple workflow:
GET /some-web-page
X-Cache: MISS
GET /some-web-page

40. Simple workflow:
GET /some-web-page
X-Cache: MISS
GET /some-web-page
First request to the page - Time To Load 200ms

41. Simple workflow:

42. Simple workflow:
GET /some-web-page

43. Simple workflow:
GET /some-web-page
X-Cache: HIT

44. Simple workflow:
GET /some-web-page
X-Cache: HIT

45. Simple workflow:
GET /some-web-page
X-Cache: HIT

46. Simple workflow:
GET /some-web-page
X-Cache: HIT
Subsequent request to the page - Time To Load 10ms

47. Idea: do not ask your backend
as much as possible.

48. How to speed up your site
with Varnish?

49. How to speed up your site
with Varnish?

50. Read the RFC 7232-7234
Your friends:
https://tools.ietf.org/html/rfc7234 - Caching
https://tools.ietf.org/html/rfc7232 - Conditional requests

51. Read the RFC 7232-7234
‣ Cache-Control
Your friends:
https://tools.ietf.org/html/rfc7234 - Caching
https://tools.ietf.org/html/rfc7232 - Conditional requests

52. Read the RFC 7232-7234
‣ Cache-Control
‣ Expires
Your friends:
https://tools.ietf.org/html/rfc7234 - Caching
https://tools.ietf.org/html/rfc7232 - Conditional requests

53. Read the RFC 7232-7234
‣ Cache-Control
‣ Expires
‣ ETag
Your friends:
https://tools.ietf.org/html/rfc7234 - Caching
https://tools.ietf.org/html/rfc7232 - Conditional requests

54. Read the RFC 7232-7234
‣ Cache-Control
‣ Expires
‣ ETag
‣ Last-Modified
Your friends:
https://tools.ietf.org/html/rfc7234 - Caching
https://tools.ietf.org/html/rfc7232 - Conditional requests

55. Install Varnish
https://www.varnish-cache.org/releases/index.html - Releases and installation guides
For Debian
For FreeBSD
Also available for Amazon Web Services

56. Configure the backend

57. Configure the backend

58. Time for experiments!

59. Test page with 3 widgets, emulating slow query

60. Test page with 3 widgets, emulating slow query

61. …our simple slow action implementation

62. …our simple slow action implementation

63. +0.2s +0.5s
+1s

64. Sequential page loads: ~1 second!
+0.2s +0.5s
+1s

65. Slow PHP? Slow Symfony?
Slow backend?

67. Make your responses HTTP
Cacheable with Varnish

68. Make your responses HTTP
Cacheable with Varnish

69. Make your responses HTTP
Cacheable with Varnish

70. Looks good…

71. Looks good…

72. Looks good…

73. …until the cache expires

74. …until the cache expires

75. …until the cache expires

76. Pros and cons of simple
cacheing
+ Page can be cached by Varnish, allowing for
faster responses.
+ Very simple to configure and use.
- Delays in the response time after cache expiration.
- We can not update information in the blocks
without a full page refresh.
- We need to render all 3 blocks at once.

77. How can we avoid delays on cache
expiration?

78. Make your backend
requests asynchronous!

79. Make your backend
requests asynchronous!

80. Make your backend
requests asynchronous!

81. Make your backend
requests asynchronous!

82. Serving stale content while invalidating

83. Serving stale content while invalidating

84. Serving stale content while invalidating

85. Serving stale content while invalidating

86. Serving stale content while invalidating

87. Pros and cons of async
cacheing
+ Page can be cached by Varnish, allowing for
faster responses.
+ Very simple to configure and use.
+ No delays after cache expiration.
- We can not update information in the blocks
without full page refresh.
- We need to render all 3 blocks at once.

88. How can we update each widget
separately on the page?

89. Enable Edge-Side Includes
(ESI)

90. Enable Edge-Side Includes
(ESI)

91. Enable Edge-Side Includes
(ESI)

92. Enable Edge-Side Includes
(ESI)

93. Enable Edge-Side Includes
(ESI)

94. Enable Edge-Side Includes
(ESI)

95. Enable Edge-Side Includes
(ESI)

96. Common mistake - missed cache header
for an ESI block!

97. Common mistake - missed cache header
for a ESI block!

98. Common mistake - missed cache header
for a ESI block!

99. Page with ESI-blocks

100. Page with ESI-blocks

101. Pros and cons of async ESI
cacheing
+ Page can be cached by Varnish, allowing for faster
responses.
+ No delays after cache expiration.
+ We can update information in the blocks without
full page refresh.
+ We render and cache each block separately. This
will result in less memory usage and better hit rate.
- Can be dangerous if used without control.

102. VCL tricks for better performance

103. Those cookies…

104. Those cookies…

105. Tips:

106. Tips:
‣ Always cache top-level GET-responses;
remove any cookies for them.

107. Tips:
‣ Always cache top-level GET-responses;
remove any cookies for them.
‣ Only ESI blocks can receive the session
cookie.

108. Tips:
‣ Always cache top-level GET-responses;
remove any cookies for them.
‣ Only ESI blocks can receive the session
cookie.
‣ Stateless ESI-blocks will not receive any
cookies at all.

109. Remove all cookies except
session one

110. Remove all cookies except
session one

111. Remove all cookies except
session one

112. Restore cookie for ESI
requests

113. Restore cookie for ESI
requests

114. Preparing cookies

115. Preparing cookies

116. Preparing cookies

117. Cacheing with cookies

118. Cacheing with cookies

119. Cacheing with cookies

120. What you will receive?

121. Some live results

122. Some live results

123. There are only two hard things in
Computer Science:
cache invalidation and naming
things.
-- Phil Karlton

124. Defining the ACL for Varnish

125. Defining the ACL for Varnish

126. Defining the ACL for Varnish

127. Preparing friendly headers

128. Performing PURGE requests

129. Performing PURGE requests

130. Performing PURGE requests

131. Single page refresh

132. Single page refresh

133. Use FOSHttpCache
http://foshttpcache.readthedocs.io/en/stable/index.html - FOSHttpCache Documentation
https://github.com/FriendsOfSymfony/FOSHttpCache - Source code

135. Thank you for your attention!
https://github.com/lisachenko
https://twitter.com/lisachenko