Varnish In Action - PHP.gent 2017

Varnish talk at the PHP.gent meetup. More information: https://talks.feryn.eu/talks/167/varnish-in-action-ghent-php-meetup-gent

Transcript

1. Varnish In Action By Thijs Feryn
2. Slow websites suck
3. Web performance is an essential part of the user experience
4. Down Slowdown ~ downtime
5. Hi, I’m Thijs
6. I’m @ThijsFeryn on Twitter
7. I’m an Evangelist At
10. https://www.facebook.com/fcbruges.support/
11. Mo money Mo servers
12. Cache
13. Don’t recompute if the data hasn’t changed
15. Normally User Server
16. With Varnish User Varnish Server
18. Why is it so good?
19. Smart kernel tricks
20. Stores HTTP output in memory*
21. Respects HTTP best practices
22. Varnish Configuration Language
23. What about TLS/SSL?
24. I'll talk about Varnish 4
25. Quick install & configure
26. apt-get install apt-transport-https curl https://repo.varnish-cache.org/GPG-key.txt | apt-key add - echo "deb https://repo.varnish-cache.org/debian/ jessie varnish-4.1"\ >> /etc/apt/sources.list.d/varnish-cache.list apt-get update apt-get install varnish Install on Linux (Debian) There's stuff for Ubuntu, RHEL & CentOS too
27. -a :80 \ -a :81,PROXY \ -T localhost:6082 \ -f /etc/varnish/default.vcl \ -S /etc/varnish/secret \ -s malloc,3g Simple config
28. vcl 4.0; backend default { .host = "localhost"; .port = "8080"; } Minimal VCL
29. Varnish speaks HTTP
30. ✓Idempotence ✓State ✓Expiration ✓Conditional requests ✓Cache variations Varnish speaks HTTP
31. ✓GET ✓HEAD -POST -PUT -PATCH -DELETE -TRACE -OPTIONS Idempotence Only cache GET & HEAD
32. ✓Doesn't cache when cookies are present ✓Doesn't cache when cookies are set ✓Doesn't cache when Authorization headers are present State Avoids caching user- specific content Affects hit rate
33. Expiration Expires: Sat, 09 Sep 2017 14:30:00 GMT Cache-control: public, max-age=3600, s-maxage=86400 Cache-control: private, no-cache, no-store
34. Expiration precedence 1. beresp.ttl (VCL) 2. s-maxage 3. max-age 4. expires 5. 120 seconds by default
35. Conditional requests HTTP/1.1 200 OK Host: localhost Etag: 7c9d70604c6061da9bb9377d3f00eb27 Content-type: text/html; charset=UTF-8 Hello world output GET /if_none_match.php HTTP/1.1 Host: localhost User-Agent: curl/7.48.0
36. Conditional requests HTTP/1.0 304 Not Modified Host: localhost Etag: 7c9d70604c6061da9bb9377d3f00eb27 GET /if_none_match.php HTTP/1.1 Host: localhost User-Agent: curl/7.48.0 If-None-Match: 7c9d70604c6061da9bb9377d3f00eb27
37. Conditional requests HTTP/1.1 200 OK Host: localhost Last-Modified: Fri, 22 Jul 2016 10:11:16 GMT Content-type: text/html; charset=UTF-8 Hello world output GET /if_none_match.php HTTP/1.1 Host: localhost User-Agent: curl/7.48.0
38. Conditional requests HTTP/1.0 304 Not Modified Host: localhost Last-Modified: Fri, 22 Jul 2016 10:11:16 GMT GET /if_none_match.php HTTP/1.1 Host: localhost User-Agent: curl/7.48.0 If-Modified-Since: Fri, 22 Jul 2016 10:11:16 GMT
39. ✓Hostname (or IP) ✓URL Cache variations Identify object in cache
40. Cache variations GET / HTTP/1.1 Host: localhost Accept-Language: nl HTTP/1.1 200 OK Host: localhost Vary: Accept-Language Hallo, deze pagina is in het Nederlands geschreven.
41. Built-in VCL cheat sheet
42. ✓Only GET & HEAD ✓No Cookie ✓No Authorization Built-in VCL (frontend) Lookup in cache Otherwise pass and don't cache
43. ✓No Set-Cookie ✓TTL > 0 ✓No "no-cache", "private", "no-store" Built-in VCL (backend) Store in cache Otherwise blacklist for 120s
44. The actual VCL code
45. sub vcl_recv { if (req.method == "PRI") { /* We do not support SPDY or HTTP/2.0 */ return (synth(405)); } if (req.method != "GET" && req.method != "HEAD" && req.method != "PUT" && req.method != "POST" && req.method != "TRACE" && req.method != "OPTIONS" && req.method != "DELETE") { /* Non-RFC2616 or CONNECT which is weird. */ return (pipe); } if (req.method != "GET" && req.method != "HEAD") { /* We only deal with GET and HEAD by default */ return (pass); } if (req.http.Authorization || req.http.Cookie) { /* Not cacheable by default */ return (pass); } return (hash); }
46. sub vcl_pipe { # By default Connection: close is set on all piped requests, to stop # connection reuse from sending future requests directly to the # (potentially) wrong backend. If you do want this to happen, you can undo # it here. # unset bereq.http.connection; return (pipe); } sub vcl_pass { return (fetch); } sub vcl_hash { hash_data(req.url); if (req.http.host) { hash_data(req.http.host); } else { hash_data(server.ip); } return (lookup); }
47. sub vcl_purge { return (synth(200, "Purged")); } sub vcl_hit { if (obj.ttl >= 0s) { // A pure unadultered hit, deliver it return (deliver); } if (obj.ttl + obj.grace > 0s) { // Object is in grace, deliver it // Automatically triggers a background fetch return (deliver); } // fetch & deliver once we get the result return (miss); } sub vcl_miss { return (fetch); } sub vcl_deliver { return (deliver); }
48. sub vcl_backend_fetch { return (fetch); } sub vcl_backend_response { if (beresp.ttl <= 0s || beresp.http.Set-Cookie || beresp.http.Surrogate-control ~ "no-store" || (!beresp.http.Surrogate-Control && beresp.http.Cache-Control ~ "no-cache|no- store|private") || beresp.http.Vary == "*") { /* * Mark as "Hit-For-Pass" for the next 2 minutes */ set beresp.ttl = 120s; set beresp.uncacheable = true; } return (deliver); }
49. Reality sucks
52. Cache-control ?
53. Legacy
54. Write VCL
55. Normalize
56. vcl 4.0; import std; sub vcl_recv { set req.http.Host = regsub(req.http.Host, ":[0-9]+", ""); set req.url = std.querysort(req.url); if (req.url ~ "\#") { set req.url = regsub(req.url, "\#.*$", ""); } if (req.url ~ "\?$") { set req.url = regsub(req.url, "\?$", ""); } if (req.restarts == 0) { if (req.http.Accept-Encoding) { if (req.http.User-Agent ~ "MSIE 6") { unset req.http.Accept-Encoding; } elsif (req.http.Accept-Encoding ~ "gzip") { set req.http.Accept-Encoding = "gzip"; } elsif (req.http.Accept-Encoding ~ "deflate") { set req.http.Accept-Encoding = "deflate"; } else { unset req.http.Accept-Encoding; } } } }
57. sub vcl_recv { if (req.url ~ "^/status\.php$" || req.url ~ "^/update\.php$" || req.url ~ "^/admin$" || req.url ~ "^/admin/.*$" || req.url ~ "^/user$" || req.url ~ "^/user/.*$" || req.url ~ "^/flag/.*$" || req.url ~ "^.*/ajax/.*$" || req.url ~ "^.*/ahah/.*$") { return (pass); } } URL blacklist
58. sub vcl_recv { if (req.url ~ "^/products/?" return (hash); } } URL whitelist
59. Cookies
60. vcl 4.0; sub vcl_recv { set req.http.Cookie = regsuball(req.http.Cookie, "has_js=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "__utm.=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "_ga=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "_gat=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "utmctr=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "utmcmd.=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "utmccn.=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "__gads=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "__qc.=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "__atuv.=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "^;\s*", ""); if (req.http.cookie ~ "^\s*$") { unset req.http.cookie; } } Remove tracking cookies
61. vcl 4.0; sub vcl_recv { if (req.http.Cookie) { set req.http.Cookie = ";" + req.http.Cookie; set req.http.Cookie = regsuball(req.http.Cookie, "; +", ";"); set req.http.Cookie = regsuball(req.http.Cookie, ";(PHPSESSID)=", "; \1="); set req.http.Cookie = regsuball(req.http.Cookie, ";[^ ][^;]*", ""); set req.http.Cookie = regsuball(req.http.Cookie, "^[; ]+|[; ]+$", ""); if (req.http.cookie ~ "^\s*$") { unset req.http.cookie; } } } Only keep session cookie
62. sub vcl_recv { if (req.http.Cookie) { set req.http.Cookie = ";" + req.http.Cookie; set req.http.Cookie = regsuball(req.http.Cookie, "; +", ";"); set req.http.Cookie = regsuball(req.http.Cookie, ";(language)=", "; \1="); set req.http.Cookie = regsuball(req.http.Cookie, ";[^ ][^;]*", ""); set req.http.Cookie = regsuball(req.http.Cookie, "^[; ]+|[; ]+$", ""); if (req.http.cookie ~ "^\s*$") { unset req.http.cookie; return(pass); } return(hash); } } sub vcl_hash { hash_data(regsub( req.http.Cookie, "^.*language=([^;]*);*.*$", "\1" )); } Language cookie cache variation
63. Or just use vmod_cookie
64. Alternative language cache variation
65. sub vcl_hash { hash_data(req.http.Accept-Language); } HTTP/1.1 200 OK Host: localhost Vary: Accept-Language Hash language Or just use
66. Cookie guidelines
67. ✓Don't throw everything in a session ✓Use dedicated cookies ✓Strip off tracking cookies in VCL ✓Match cookies in VCL & make decisions ✓Perform cache variations on cookie values ✓Only use session cookies when you really have to ✓Use JWT to store session state client-side Cookie guidelines
68. Block caching
70. Code renders single HTTP response
71. Lowest common denominator: no cache
72. <esi:include src="/header" /> Edge Side Includes ✓Placeholder ✓Parsed by Varnish ✓Output is a composition of blocks ✓State per block ✓TTL per block
73. sub vcl_recv { set req.http.Surrogate-Capability = "key=ESI/1.0"; } sub vcl_backend_response { if (beresp.http.Surrogate-Control ~ "ESI/1.0") { unset beresp.http.Surrogate-Control; set beresp.do_esi = true; } } Edge Side Includes
74. ESI vs AJAX
75. <esi:include src="/header" /> Choose wisely <hx:include src="/header"></hx:include> ESI, parsed by Varnish HInclude, parsed by Javascript
76. Measure the pressure
77. ✓Varnishlog ✓Varnishtop ✓Varnishstat Measure the pressure
78. Breaking news isn't breaking
79. Purging
80. acl purge { "localhost"; "127.0.0.1"; "::1"; } sub vcl_recv { if (req.method == "PURGE") { if (!client.ip ~ purge) { return (synth(405, “Not allowed.”)); } return (purge); } } Purging
81. acl purge { "localhost"; "127.0.0.1"; "::1"; } sub vcl_backend_response { set beresp.http.x-url = bereq.url; set beresp.http.x-host = bereq.http.host; } sub vcl_deliver { unset resp.http.x-url; unset resp.http.x-host; } sub vcl_recv { if (req.method == "PURGE") { if (!client.ip ~ purge) { return (synth(405, "Not allowed")); } if(req.http.x-purge-regex) { ban("obj.http.x-host == " + req.http.host + " && obj.http.x-url ~ " + req.http.x-purge-regex); } else { ban("obj.http.x-host == " + req.http.host + " && obj.http.x-url == " + req.url); } return (synth(200, "Purged")); } } Banning
82. Banning curl -XPURGE "http://example.com/products" curl -XPURGE -H "x-purge-regex:/products" \ "http://example.com" varnishadm> ban obj.http.x-host == example.com && obj.http.x-url ~ ^/product/[0-9]+/details
83. Write less VCL Write more code
84. https://github.com/ThijsFeryn/ cacheable-site-silex/tree/v2
87. https://twitter.com/thijsferyn https://instagram.com/thijsferyn https://blog.feryn.eu https://talks.feryn.eu https://book.feryn.eu https://youtube.com/thijsferyn https://soundcloud.com/thijsferyn http://itunes.feryn.eu