PHP London Dec 2013 - Varnish - The 9 circles of hell

Varnish
The 9 circles of hell
By

04 Dec 2013

Who am i
●
●

●

Luis Ferro
Lead Developer in Rewards and Loyalty
Programs (Metropolis International)
When not coding, you can find me shooting
arrows or cooking, mostly...

http://www.linkedin.com/profile/view?id=73429631

Varnish before Hell Entrance
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“Varnish is an HTTP accelerator designed for
content-heavy dynamic web sites. Varnish is
focused exclusively on HTTP.” - wikipedia

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https://www.varnish-cache.org

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Installing (debian/ubuntu)
sudo apt-get update
sudo apt-get install varnish

st

1 Circle - basics
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Simple caching

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Varnish, NGinX and PHP should be working

●

Default configurations apart from the ports
which should be:
Port 80 – Varnish, with backend to 8080
Port 8080 – NGinX, with backend to 9000
Port 9000 – PHP

st

1 – Backend in default.vcl
backend default {
.host = "127.0.0.1";
.port = "8080";
.connect_timeout = 30s;
.first_byte_timeout = 30s;
.between_bytes_timeout = 30s;
}
Check configuration with:
varnishd -C -f default.vcl

st

1 - Checking it in - NGinX
NGinX Test
ab -n 10000 -c 10 http://127.0.0.1:8080/index.php

Requests per second:

253.01 [#/sec] (mean)

Time per request:

39.524 [ms] (mean)

Time per request:

3.952 [ms] (mean, across all concurrent requests)

Transfer rate:

29931.75 [Kbytes/sec] received

st

1 - Checking it in - Varnish
Varnish Test
ab -n 10000 -c 10 http://127.0.0.1:80/index.php

Requests per second:

2624.59 [#/sec] (mean)

Time per request:

3.810 [ms] (mean)

Time per request:

0.381 [ms] (mean, across all concurrent requests)

Transfer rate:

311418.96 [Kbytes/sec] received

10x FASTER
With almost default config

nd

2 Circle – The path to cache
●

Add hit / miss information to all requests
sub vcl_deliver {
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT";
set resp.http.X-Cache-Hits = obj.hits;
} else {
set resp.http.X-Cache = "MISS";
}
return (deliver);
}

rd

3 Circle – Force march
●

Force Refresh
sub vcl_recv { [...]
if (req.http.Cache-Control ~ "no-cache") {
ban_url(req.url);
}
[…] }

●

You may want to protect / restrict who can call
this “ban”

rd

4 Circle – Expired content
●

Add php headers to force content to expire after
a certain quantity of seconds
function headers_for_page_cache($cache_length=600){
$cache_expire_date = gmdate("D, d M Y H:i:s", time() + $cache_length);
header("Expires: $cache_expire_date");
header("Pragma: cache");
header("Cache-Control: max-age=$cache_length, s-maxage=$cache_length");
header("User-Cache-Control: max-age=$cache_length");
}

th

5 Circle – All in the bag
●

Ensure cache by delete cookies on unwanted
items (images, css, js)
sub vcl_recv { […]
if (req.url ~ ".(png|gif|jpg)$") {
remove req.http.Cookie;
}
[...]}

●

Varnish doesn't cache anything with a cookie!

th

6 Circle – Watch your steps
●

Install GeoIp

●

Get GeoipUsingInlineC from:
https://www.varnish-cache.org/trac/wiki/GeoipUsingInlineC

●

Compile and install it (findable by your OS)

th

6 - Geoip.vcl
C{
#include <dlfcn.h>
#include <stdlib.h>
#include <stdio.h>
static const char* (*get_country_code)(char* ip) = NULL;
__attribute__((constructor)) void
load_module()
{
const char* symbol_name = "get_country_code";
const char* plugin_name = "/usr/lib/geoip_plugin.so";
void* handle = NULL;
handle = dlopen( plugin_name, RTLD_NOW );
if (handle != NULL) {
get_country_code = dlsym( handle, symbol_name );
if (get_country_code == NULL)
fprintf( stderr, "nError: Could not load GeoIP plugin:n%snn", dlerror() );
else
printf( "GeoIP plugin loaded successfully.n");
}
else
fprintf( stderr, "nError: Could not load GeoIP plugin:n%snn", dlerror() );
}
}C

th

6 - Add it to default.vcl
C{
VRT_SetHdr(sp, HDR_REQ, "017X-Country-Code:",
(*get_country_code)( VRT_IP_string(sp, VRT_r_client_ip(sp)) ),
vrt_magic_string_end);
}C
[…] }

th

7 Circle – Know your enemies
●

Device Detection

●

Download the devicedetection.vcl from:
http://github.com/varnish/varnish-devicedetect/

●

Add it to default.vcl
call detectdevice;
[…] }

th

8 Circle – Tongue in cheek
●

Accepted language

●

Download and create the accept-language.vcl from:
http://github.com/cosimo/varnish-accept-language

●

Include the generated file and call it in default.vcl
C{
vcl_rewrite_accept_language(sp);
}C
[…] }

th

9 Circle – Divide and conquer
●

To activate add in your default.vcl
sub vcl_fetch { [...]
if( beresp.http.esi-enabled == "1") {
set beresp.do_esi = true; /* Do ESI processing */
set beresp.ttl = 120s; /* Sets the TTL on the HTML
above */
unset beresp.http.esi-enabled;
} [...]

th

9 - Check

Remember, ESI has issues with non-xml like files. So, the file where you
place the <esi: instructions have to look like a xml file.

More to come... if there was time...
●

Redirects

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ESI – Sessions / Users

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Purge

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SSL / SPDY / Compression

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Load Balancing

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Webserver (O.o really?)

Varnish Resources
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The Book
https://www.varnish-software.com/static/book/

●

Cache Tutorial
http://www.mnot.net/cache_docs/

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Slides (slides used on the talk)
Slides will be made available later on slideshare

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Sourcecode (configs, test scripts, etc)
GitHub: https://github.com/lferro9000/varnish-talk

Thank you for listening and...
●

●

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… Specially to varnish-software and everyone that
somehow contributed directly to enrich varnish.
Always check varnish-software website in case of doubt,
there is an huge amount of little tricks there.
Remember: using varnish, is good for the environment
(less power = win)!

Credits and Thanks
●

Botticelli Chart of Dante's Hell
http://www.flickr.com/photos/distan/3708997567/
by Dina Dubrovskaya (Real Distan)

●

The great people that made Varnish possible

●

PHP London for accepting this talk

PHP London Dec 2013 - Varnish - The 9 circles of hell

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