Varnish in-depth training - Symfony Live Berlin 2017

By Thijs Feryn Varnish in -depth training

Slow websites suck

Web performance is an essential part of the user experience

Slow ~ Down

Saturated market

Heavy load

Mo money Mo servers

Identify slowest parts

Reduce the impact of the code on the server

Not just raw speed

Refactor slow code Write fast code

Optimize database

Improve the API call

Optimize runtime

After a while you hit the limits

Don’t recompute if the data hasn’t changed

3 x 2 = ?

What can you cache? Byte code Database output External services
Files from disk Pages

Caching is not a compensation for poor code

Caching is an essential architectural strategy

Normally User Server

With Varnish User Varnish Server

Hi, I’m Thijs

I’m @ThijsFeryn on Twitter

I’m an Evangelist At

I’m a at board member

Let's dive right in!

Varnish

Cache?

Loadbalancer?

Proxy?

Web application firewall?

HTTP accelerator

Regular proxy User Proxy Server Office

With reverse proxy User Proxy Server Datacenter

Bit of history

Varnish Moral License http://phk.freebsd.dk/VML/

Main project “sponsors”

How does it work?

varnishd VCL file Compiled & linked as shared object Client
HTTP Backend HTTP Memory Logs Writes verbose “transaction” logs to memory varnishlog varnishtop Read memory logs, displays information varnishncsa varnishadm Allow basic management tasks Custom protocol

Install & configure

https://packagecloud.io/varnishcache/varnish5 https://packagecloud.io/varnishcache/varnish41

$ curl -s https://packagecloud.io/install/repositories/ varnishcache/varnish5/script.deb.sh | sudo bash $ apt-get
install varnish Debian & Ubuntu

$ apt-cache policy varnish varnish: Installed: 5.2.0-1~stretch Candidate: 5.2.0-1~stretch Version
table: *** 5.2.0-1~stretch 500 500 https://packagecloud.io/varnishcache/varnish5/debian stretch/main amd64 Packages 100 /var/lib/dpkg/status 5.1.3-1~stretch 500 500 https://packagecloud.io/varnishcache/varnish5/debian stretch/main amd64 Packages 5.1.2-1~stretch 500 500 https://packagecloud.io/varnishcache/varnish5/debian stretch/main amd64 Packages 5.0.0-7+deb9u1 500 500 http://deb.debian.org/debian stretch/main amd64 Packages 500 http://security.debian.org stretch/updates/main amd64 Packages

$ apt-get install varnish=5.2.0-1~stretch

$ curl -s https://packagecloud.io/install/repositories/ varnishcache/varnish5/script.rpm.sh | sudo bash $ yum
install varnish RHEL & CentOS

Config file

SysV Systemd Ubuntu/Debian /etc/default/varnish /etc/systemd/system/varnish.service RHEL/CentOS /etc/sysconfig/varnish /etc/varnish/varnish.params

cp /lib/systemd/system/varnish.service \ /etc/systemd/system/ Copy defaults file Ubuntu & Debian
with systemd

Startup options

[Unit] Description=Varnish Cache, a high-performance HTTP accelerator [Service] Type=forking #
Maximum number of open files (for ulimit -n) LimitNOFILE=131072 # Locked shared memory - should suffice to lock the shared memory log # (varnishd -l argument) # Default log size is 80MB vsl + 1M vsm + header -> 82MB # unit is bytes LimitMEMLOCK=85983232 # On systemd >= 228 enable this to avoid "fork failed" on reload. #TasksMax=infinity # Maximum size of the corefile. LimitCORE=infinity # Set WARMUP_TIME to force a delay in reload-vcl between vcl.load and vcl.use # This is useful when backend probe definitions need some time before declaring # configured backends healthy, to avoid routing traffic to a non-healthy backend. #WARMUP_TIME=0 ExecStart=/usr/sbin/varnishd -a :80 -T localhost:6082 -f /etc/varnish/default.vcl -S /etc/varnish/ secret -s malloc,256m ExecReload=/usr/share/varnish/reload-vcl [Install] WantedBy=multi-user.target Debian Stretch with systemd

$ vim /etc/systemd/system/varnish.service $ systemctl daemon-reload $ service varnish reload
Reload with systemd

DAEMON_OPTS="-a :80 \ -T localhost:6082 \ -f /etc/varnish/default.vcl \ -S
/etc/varnish/secret \ -s malloc,256m" Ubuntu Trusty without systemd

vim /etc/default/varnish service varnish reload Reload with sysv

-a: binding address & port -T: admin binding -f: VCL
file -S: secret file -s: storage -j: jailing -l: shared memory log size -t: default TTL -p: runtime parameters Options

DAEMON_OPTS="-j unix,user=www-data \ -a main=0000:80 \ -a proxy=0.0.0.0:81,PROXY \ -T
localhost:6082 \ -f /etc/varnish/default.vcl \ -S /etc/varnish/secret \ -l 100m,10m \ -t 60 \ -p feature=+esi_disable_xml_check \ -p connect_timeout=20s \ -p first_byte_timeout=100s \ -p between_bytes_timeout=5s \ -s malloc,3g"

The backend

Point of entry? Bind to 80 Otherwise 6081

8080 HTTP-ALT

Listen 8080 Apache <VirtualHost *:8080> ports.conf vhost

listen 8080; Nginx vhost

✓In VCL file ✓In config file using "-b" Link backend
to Varnish

DAEMON_OPTS="-j unix,user=www-data \ -a main=0.0.0.0:80 \ -a proxy=0.0.0.0:81,PROXY \ -T
localhost:6082 \ -b 127.0.0.1:8080 \ -S /etc/varnish/secret \ -s malloc,3g" Can't have -f In config file

vcl 4.0;    backend default {  .host = "127.0.0.1";  .port
= "8080";  } In VCL file Minimal VCL

Typical setups

All-in-one User Varnish (80) Nginx (8080)

Dedicated Varnish User Varnish (80) Nginx (80)

Multiple webservers User Varnish (80) Nginx (8080) Varnish (80) Nginx
(8080) KeepAliveD

Multiple webservers & dedicated Varnish User Varnish (80) KeepAliveD Varnish
(80) Nginx (80) Nginx (80)

Loadbalancing User Varnish (80) KeepAliveD Varnish (80) Nginx (80) Nginx
(80)

HAProxy loadbalancers User HAProxy (80) Varnish (6081) KeepAliveD HAProxy (80)
Varnish (6081) Nginx (80) Nginx (80)

Share the cache

Share the cache User Nginx (80) Nginx (80) 1 2
3 4 5 6 HAProxy (80) Varnish ( 6080 & 6081) HAProxy (80) Varnish ( 6080 & 6081)

Share the cache 2 User HAProxy (80) Varnish ( 6080
& 6081) Nginx (80) Nginx (80) 1 5 3 4 2 6 HAProxy (80) Varnish ( 6080 & 6081)

vcl 4.0; import std; backend nginx { .host = "nginx";
.port = "80"; } backend nginx2 { .host = "nginx2"; .port = "80"; } backend varnish { .host = "varnish"; .port = "6080"; } backend varnish2 { .host = "varnish2"; .port = "6080"; } sub vcl_recv { if(server.hostname == "varnish") { if(std.port(server.ip) == 6080) { set req.backend_hint = nginx; set req.http.x-esi = "yes"; } else { set req.backend_hint = varnish2; set req.http.x-esi = "no"; } } else { if(std.port(server.ip) == 6080) { set req.backend_hint = nginx2; set req.http.x-esi = "yes"; } else { set req.backend_hint = varnish; set req.http.x-esi = "no"; } } } sub vcl_backend_response { if (bereq.http.x-esi == "yes" && beresp.http.Surrogate-Control ~ "ESI/1.0") { unset beresp.http.Surrogate-Control; set beresp.do_esi = true; } }

sub vcl_recv { if(server.hostname == "varnish") { if(std.port(server.ip) == 6080)
{ set req.backend_hint = nginx; set req.http.x-esi = "yes"; } else { set req.backend_hint = varnish2; set req.http.x-esi = "no"; } } else { if(std.port(server.ip) == 6080) { set req.backend_hint = nginx2; set req.http.x-esi = "yes"; } else { set req.backend_hint = varnish; set req.http.x-esi = "no"; } } }

What about TLS/SSL?

✓HAProxy ✓Nginx ✓Pound ✓Hitch Terminate TLS/SSL

HAProxy 172.18.0.3 Varnish 172.18.0.8 Nginx Public HTTP & HTTPS HTTP
HTTP Certificates go here

How do you know if it was HTTP or HTTPS?

X-Forwarded-Proto: https X-Forwarded-Proto: http

if (strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false) $_SERVER['HTTPS']='on';

SetEnvIf X-Forwarded-Proto "https" HTTPS=on Header append Vary: X-Forwarded-Proto <IfModule mod_rewrite.c>
RewriteEngine on RewriteCond %{HTTPS} !=on RewriteCond %{HTTP:X-Forwarded-Proto} !https [NC] RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301] </IfModule>

Demo setup

https://github.com/ThijsFeryn/ varnishtraining

$ docker-compose up $ docker-compose down $ docker-compose up -d
$ docker-compose logs $ docker-compose logs -f $ docker-compose logs varnish $ docker-compose logs -f varnish

HAProxy (80 & 81) Varnish (6080, 6081, 6082, 6083) Nginx
(80) PHP-FPM (9000) Varnish 2 (6080, 6081, 6082, 6083) Nginx 2 (80) PHP-FPM 2 (9000) MySQL (3306) Redis (6379) Demo setup

✓sflive-varnish2: 172.18.0.10 ✓sflive-varnish: 172.18.0.8 ✓sflive-nginx2: 172.18.0.6 ✓sflive-nginx: 172.18.0.2 ✓sflive-php2: 172.18.0.5
✓sflive-php: 172.18.0.4 ✓sflive-haproxy: 172.18.0.3 ✓sflive-redis: 172.18.0.7 ✓sflive-mysql: 172.18.0.9 Demo setup IPs

FROM debian:stretch as builder WORKDIR /usr/lib/varnish/vmods/ RUN apt-get update \
&& apt-get install -y curl \ && curl -s https://packagecloud.io/install/repositories/varnishcache/varnish5/ script.deb.sh | bash \ && apt-get install -y unzip automake varnish=5.2.0-1~stretch varnish- dev=5.2.0-1~stretch build-essential libtool docutils-common libmhash-dev --allow- unauthenticated \ && curl -O https://download.varnish-software.com/varnish-modules/varnish- modules-0.12.1.tar.gz \ && tar xvzf varnish-modules-0.12.1.tar.gz \ && (cd varnish-modules-0.12.1 && ./configure && make && make install) \ && curl -O -L https://github.com/gquintard/libvmod-accept/archive/master.zip \ && unzip master.zip \ && (cd libvmod-accept-master && ./autogen.sh && ./configure && make && make install) \ && curl -O -L https://github.com/varnish/libvmod-digest/archive/master.zip \ && unzip master.zip \ && (cd libvmod-digest-master && ./autogen.sh && ./configure && make && make install) FROM debian:stretch WORKDIR /etc/varnish EXPOSE 6080 EXPOSE 6081 EXPOSE 6082 EXPOSE 6083 ENV SIZE 100m ENV SECRET E29F6DE6-3803-449E-8A01-AA537A8715B1 ARG BACKEND=nginx

install) \ && curl -O -L https://github.com/varnish/libvmod-digest/archive/master.zip \ && unzip
master.zip \ && (cd libvmod-digest-master && ./autogen.sh && ./configure && make && make install) FROM debian:stretch WORKDIR /etc/varnish EXPOSE 6080 EXPOSE 6081 EXPOSE 6082 EXPOSE 6083 ENV SIZE 100m ENV SECRET E29F6DE6-3803-449E-8A01-AA537A8715B1 ARG BACKEND=nginx RUN apt-get update \ && apt-get install -y curl \ && curl -s https://packagecloud.io/install/repositories/varnishcache/varnish5/ script.deb.sh | bash \ && apt-get install -y varnish=5.2.0-1~stretch libmhash-dev --no-install-recommends --allow-unauthenticated \ && rm -rf /var/lib/apt/lists/* \ && /bin/bash -c ' echo "$SECRET" > /etc/varnish/secret' \ && rm -rf /usr/lib/varnish/vmods/libvmod_*.so COPY --from=builder /usr/lib/varnish/vmods/libvmod_*.so /usr/lib/varnish/vmods/ CMD ["/bin/bash","-c","/usr/sbin/varnishd -j unix,user=varnish -s malloc,$SIZE -F -a internal=0.0.0.0:6080 -a main=0.0.0.0:6081 -a proxy=0.0.0.0:6083,PROXY -T 0.0.0.0:6082 -f /etc/varnish/default.vcl -S /etc/varnish/secret -p feature=+esi_disable_xml_check - p vsl_mask=+Hash"]

What’s the real IP? 172.18.0.1 ?

HAProxy 172.18.0.3 Varnish 172.18.0.8 Nginx Public 172.18.0.1

X-Forwarded-For

Nginx Public 172.18.0.1 Client IP: 172.18.0.1 X-Forwarded-For:

Varnish 172.18.0.8 Nginx Public 172.18.0.1 Client IP: 172.18.0.8 X-Forwarded-For: 172.18.0.1

HAProxy 172.18.0.3 Varnish 172.18.0.8 Nginx Public 172.18.0.1 Client IP: 172.18.0.8
X-Forwarded-For: 172.18.0.3

PROXY Protocol

Add original IP as TCP preamble

DAEMON_OPTS="-j unix,user=www-data \ -a :80 \ -a :81,PROXY \ -T

Varnish automatically sets X-Forwarded-For to the original IP using PROXY
protocol

HAProxy 172.18.0.3 Varnish 172.18.0.8 Nginx Public 172.18.0.1 Client IP: 172.18.0.8
X-Forwarded-For: 172.18.0.1

There are rules

✓Idempotence ✓State ✓Expiration ✓Conditional requests ✓Cache variations Varnish speaks HTTP

Idempotence Execute multiple times Result doesn't change

✓ GET ✓ HEAD - POST - PUT - DELETE
- PATCH Idempotence Result changes Result doesn't change Don't cache

State ~ user specific data Cookies Auth headers

About cookies

✓ Request header ✓ Sent by client (~browser) ✓ Sent
on every request ✓ Describes state ✓ Is not cached ✓ 3rd party tracking cookies vs own cookies About cookies Cookie: key=value;key2=value2

✓ Response header ✓ Sent by backend server ✓ Only
when backend is called ✓ Changes state ✓ Is not cached ✓ Blacklisted for 120s (by default) About cookies Set-Cookie: key=another_value

Time To Live

✓ 120s by default ✓ Respects HTTP cache-control header ✓
Respects expires header ✓ Override in VCL file Time to live

1.VCL 2.s-maxage 3.max-age 4.expires 5.Default value 120s TTL Order

Use TTL not to cache Cache-Control: max-age=0 Cache-Control: s-maxage=0 Cache-Control:
private Cache-Control: no-cache Cache-Control: no-store Expires: Fri, 1 Jan 1971 00:00:00 GMT

Combine values Cache-Control: public, maxage=1000, s-maxage=3600

Age Age: 10 How old is the cached object?

Real cache duration max-age - Age s-maxage - Age

Don’t set the Age header yourself!

Conditional requests

Only fetch payload that has changed

Otherwise: HTTP/1.1 304 Not Modified

In both directions User Varnish Server 304 Not Modified 304
Not Modified

✓ Conserve bandwidth ✓ Reduce load on the backend when
revalidating Conditional requests

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

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

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

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-Last-Modified: Fri, 22 Jul 2016 10:11:16 GMT

Store etag or modification date

Validate early on

Exit quickly

Varnish can revalidate aynchronously

And serve stale data while that happens

Grace mode

Effective TTL = TTL + grace

Cache-Control: public, max-age=100, s-maxage=3600, stale-while-revalidate=7200 Stale-While-Revalidate Set grace mode

Variations

Cache is not the same for everyone

✓ URL ✓ Hostname ✓ IP if hostname is not
set ✓ Vary header Basic variations

Vary header Vary: Accept-Encoding Vary: Accept-Language Vary: Cookie Watch out!

The flow

Varnish Configuration Language

DSL compiled and linked as shared object

/etc/varnish/default.vcl

Hooks & subroutines

VCL Recv VCL Hash VCL Miss VCL Hit VCL Backend
Response VCL Deliver VCL Purge VCL Error VCL Pipe VCL Pass VCL Synth VCL Backend Error

✓vcl_recv: receive request ✓vcl_hash: compose cache key ✓vcl_miss: not found
in cache ✓vcl_hit: found in cache ✓vcl_pass: don’t store in cache ✓vcl_pipe: bypass cache ✓vcl_backend_fetch: connect to backend ✓vcl_backend_response: response from backend ✓vcl_backend_error: backend fetch failed

✓vcl_purge: after successful purge ✓vcl_synth: send synthetic output ✓vcl_deliver: return
data to client ✓vcl_init: initialize VMODs ✓vcl_fini: discard VMODs ✓vcl_fail: stop execution

Actions

✓ hash: lookup in cache ✓ pass: don't cache ✓
synth: synthetic HTML output ✓ pipe: bypass cache ✓ purge: remove from cache VCL_RECV

✓ synth: synthetic HTML output ✓ pipe: bypass cache VCL_PIPE

✓ fetch: fetch data from backend, don't cache ✓ restart:
restart transaction ✓ synth: synthetic HTML output VCL_PASS

✓ deliver: send cached object ✓ miss: synchronous refresh despite
hit ✓ pass: fetch data from backend despite hit, don't cache ✓ restart: restart transaction ✓ synth: synthetic HTML output VCL_HIT

✓ fetch: fetch data from backend ✓ pass: fetch data
from backend, don't cache ✓ restart: restart transaction ✓ synth: synthetic HTML output VCL_MISS

✓ lookup: look for cached object by using hash key
VCL_HASH

✓ restart: restart transaction ✓ synth: synthetic HTML output VCL_PURGE

✓ deliver: deliver object to client ✓ restart: restart transaction
✓ synth: synthetic HTML output VCL_DELIVER

✓ deliver: deliver synthetic output to client ✓ restart: restart
transaction VCL_SYNTH

✓ fetch: fetch object from backend ✓ abandon: abandon request
and send HTTP 503 error VCL_BACKEND_FETCH

✓ deliver: send fetched data to client ✓ abandon: abandon
request and send HTTP 503 error ✓ retry: retry backend request VCL_BACKEND_RESPONSE

✓ deliver: send fetched data to client ✓ retry: retry
backend request VCL_BACKEND_ERROR

Typical flows

✓ vcl_recv: hash ✓ vcl_hash: lookup ✓ vcl_miss: fetch ✓
vcl_backend_request: fetch ✓ vcl_backend_response: deliver ✓ vcl_deliver: deliver MISS

✓ vcl_recv: hash ✓ vcl_hash: lookup ✓ vcl_hit: deliver ✓
vcl_deliver: deliver HIT

✓ vcl_recv: pass ✓ vcl_pass: fetch ✓ vcl_backend_request: fetch ✓
vcl_backend_response: deliver ✓ vcl_deliver: deliver PASS

Objects

✓ req: incoming request object ✓ req_top: top level esi
request ✓ bereq: request object to send to backend ✓ beresp: backend response ✓ resp: response to send back to client ✓ obj: cached object ✓ client: client information ✓ server: server information ✓ local: local TCP information ✓ remote: remote TCP information ✓ storage: storage information VCL Objects

Variables

✓ req.url ✓ req.http.host ✓ req.http.user-agent ✓ req.backend_hint ✓ req.method
✓ … req variables

✓ bereq.backend ✓ bereq.http.user-agent ✓ bereq.method ✓ bereq.url ✓ …
bereq variables

✓ beresp.age ✓ beresp.backend.ip ✓ beresp.backend.name ✓ beresp.do_esi ✓ beresp.grace
✓ beresp.keep ✓ beresp.http.set-cookie ✓ beresp.ttl ✓ beresp.status ✓ beresp.uncacheable beresp variables

✓ client.ip ✓ client.identity client variables local variables ✓ local.ip
remote variables ✓ remote.ip

✓ obj.age ✓ obj.grace ✓ obj.hits ✓ obj.http.cache-control ✓ obj.reason
✓ obj.status ✓ obj.ttl object variables

✓ resp.http.user-agent ✓ resp.is_streaming ✓ resp.reason ✓ resp.status resp variables

✓ storage.<name>.free_space ✓ storage.<name>.used_space ✓ storage.<name>.happy storage variables

Default behaviour

vcl 4.0; sub vcl_recv { if (req.method == "PRI") {
return (synth(405)); } if (req.method != "GET" && req.method != "HEAD" && req.method != "PUT" && req.method != "POST" && req.method != "TRACE" && req.method != "OPTIONS" && req.method != “PATCH" && req.method != "DELETE") { return (pipe); } if (req.method != "GET" && req.method != "HEAD") { return (pass); } if (req.http.Authorization || req.http.Cookie) { return (pass); } return (hash); } Idempotence State Action Receive request

sub vcl_hash { hash_data(req.url); if (req.http.host) { hash_data(req.http.host); } else
{ hash_data(server.ip); } return (lookup); } Lookup in cache Variations Action

sub vcl_purge { return (synth(200, "Purged")); } sub vcl_hit {
if (obj.ttl >= 0s) { return (deliver); } if (obj.ttl + obj.grace > 0s) { return (deliver); } return (miss); } sub vcl_miss { return (fetch); } sub vcl_deliver { return (deliver); } Remove from cache Found in cache Not found in cache Return HTTP response to client

sub vcl_synth { set resp.http.Content-Type = "text/html; charset=utf-8"; set resp.http.Retry-After
= "5"; synthetic( {"<!DOCTYPE html> <html> <head> <title>"} + resp.status + " " + resp.reason + {"</title> </head> <body> <h1>Error "} + resp.status + " " + resp.reason + {"</h1> <p>"} + resp.reason + {"</p> <h3>Guru Meditation:</h3> <p>XID: "} + req.xid + {"</p> <hr> <p>Varnish cache server</p> </body> </html> "} ); return (deliver); } Send custom HTML

sub vcl_backend_fetch { return (fetch); } sub vcl_backend_response { if
(bereq.uncacheable) { return (deliver); } else 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 == "*") { set beresp.ttl = 120s; set beresp.uncacheable = true; } return (deliver); } Send backend request Receive backend response TTL State Receive backend response

sub vcl_backend_error { set beresp.http.Content-Type = "text/html; charset=utf-8"; set beresp.http.Retry-After
= "5"; synthetic( {"<!DOCTYPE html> <html> <head> <title>"} + beresp.status + " " + beresp.reason + {"</title> </head> <body> <h1>Error "} + beresp.status + " " + beresp.reason + {"</h1> <p>"} + beresp.reason + {"</p> <h3>Guru Meditation:</h3> <p>XID: "} + bereq.xid + {"</p> <hr> <p>Varnish cache server</p> </body> </html> "} ); return (deliver); } Send custom HTML on backend error

Minimal VCL

vcl 4.0; backend default { .host = "127.0.0.1"; .port =
"8080"; } Minimal VCL

"80"; .max_connections = 300; .first_byte_timeout = 300s; .connect_timeout = 5s; .between_bytes_timeout = 2s; } More backend work

"80"; .max_connections = 300; .first_byte_timeout = 300s; .connect_timeout = 5s; .between_bytes_timeout = 2s; .probe = { .url = "/"; .interval = 5s; .timeout = 1s; .window = 5; .threshold = 3; } } Even more backend work

"80"; .max_connections = 300; .first_byte_timeout = 300s; .connect_timeout = 5s; .between_bytes_timeout = 2s; .probe = { .request = "HEAD / HTTP/1.1" "Host: localhost" "Connection: close" "User-Agent: Varnish Health Probe"; .interval = 5s; .timeout = 1s; .window = 5; .threshold = 3; } } Even more backend work

Varnish modules

Written in C

Exposes new VCL objects

Added functionality

vcl 4.0; import directors; import std; import cookie; sub vcl_init
{ new vdir = directors.round_robin(); vdir.add_backend(…); vdir.add_backend(…); } VMOD

vmod_std

sub vcl_recv { if(std.file_exists("/etc/varnish/file.txt")) { return(synth(200,std.fileread("/etc/varnish/file.txt"))); } else { return(synth(200,"File
does not exist")); } } std.fileread

sub vcl_recv { return(synth(200,"FOO: " + std.getenv("FOO"))); } std.getenv

vcl 4.0; import std; backend default { .host = "nginx";
.port = "80"; .probe = { .url = "/"; .interval = 1s; .timeout = 1s; .window = 5; .threshold = 3; } } sub vcl_recv { if(std.healthy(req.backend_hint)) { return(synth(200,"Backend is healthy")); } else { return(synth(200,"Backend is unhealthy")); } } std.healthy

sub vcl_recv { std.timestamp("Before std.log"); std.log("This should appear in the
Shared Memory Log"); std.timestamp("After std.log"); std.syslog(9,"This should appear in the Syslog"); std.timestamp("After std.syslog"); return(synth(200,"OK")); } Logging

sub vcl_recv { return(synth(200,"Client port: " + std.port(client.ip) + ",
server port: " + std.port(server.ip))); } std.port

sub vcl_recv { return(synth(200,"Unsorted: " + regsub(req.url,"\?(.+)$","\1") + ", sorted:
" + regsub(std.querysort(req.url),"\?(.+)$","\1"))); } std.querysort

sub vcl_recv { return(synth(200,std.real2integer(std.random(1,10),0))); } std.random & std.real2integer

sub vcl_recv { return(synth(200,std.toupper("yes") + " " + std.tolower("YES"))); }
std.toupper & std.tolower

https://varnish-cache.org/docs/5.2/ reference/vmod_std.generated.html

Load balancing

vcl 4.0; import directors; backend server1 { .host = “1.2.3.4”;
.port = "80"; .max_connections = 300; .first_byte_timeout = 300s; .connect_timeout = 5s; .between_bytes_timeout = 2s; .probe = { .request = "HEAD / HTTP/1.1" "Host: localhost" "Connection: close" "User-Agent: Varnish Health Probe"; .interval = 5s; .timeout = 1s; .window = 5; .threshold = 3; } } Loadbalancing: server 1

backend server2 { .host = “1.2.3.5”; .port = "80"; .max_connections
= 300; .first_byte_timeout = 300s; .connect_timeout = 5s; .between_bytes_timeout = 2s; .probe = { .request = "HEAD / HTTP/1.1" "Host: localhost" "Connection: close" "User-Agent: Varnish Health Probe"; .interval = 5s; .timeout = 1s; .window = 5; .threshold = 3; } } Loadbalancing: server 2

sub vcl_init { new vdir = directors.round_robin(); vdir.add_backend(server1); vdir.add_backend(server2); }
sub vcl_recv { set req.backend_hint = vdir.backend(); } Loadbalancing: round robin

sub vcl_init { new vdir = directors.random(); vdir.add_backend(server1,2); vdir.add_backend(server2,3); }
sub vcl_recv { set req.backend_hint = vdir.backend(); } Loadbalancing: random

sub vcl_init { new vdir = directors.fallback(); vdir.add_backend(server1); vdir.add_backend(server2); }
sub vcl_recv { set req.backend_hint = vdir.backend(); } Loadbalancing: fallback

sub vcl_init { new vdir = directors.hash(); vdir.add_backend(server1); vdir.add_backend(server2); }
sub vcl_recv { set req.backend_hint = vdir.backend(req.url); } Loadbalancing: URL hash

sub vcl_init { new vdir = directors.hash(); vdir.add_backend(server1); vdir.add_backend(server2); }
sub vcl_recv { set req.backend_hint = vdir.backend(client.identity); } Loadbalancing: IP hash

sub vcl_recv { if(req.url ~ “^/products”) { set req.backend_hint =
server1; } else { set req.backend_hint = server2; } } Conditional loadbalancing

Install other VMODs

apt-get install -y varnish varnish-dev build-essential curl -O https://download.varnish-software.com/varnish- modules/varnish-modules-0.12.1.tar.gz
tar xvzf varnish-modules-0.12.1.tar.gz cd varnish-modules-0.12.1 ./configure make make install Install official VMODs

apt-get install -y varnish varnish-modules Install basic VMODs If you
install Varnish 5.0.0 via Debian repo

vmod_cookie

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; } } } Without vmod_cookie

vcl 4.0; import cookie; sub vcl_recv { if (req.http.cookie) {
cookie.parse(req.http.cookie); cookie.filter_except("PHPSESSID"); set req.http.cookie = cookie.get_string(); if (req.http.cookie ~ "^\s*$") { unset req.http.cookie; } } } With vmod_cookie

vcl 4.0; import cookie; sub vcl_recv { cookie.parse(req.http.cookie); if(cookie.isset("PHPSESSID")) {
return(synth(200,"PHPSESSID is set and contains the following value: <em>" + cookie.get("PHPSESSID") + "</em>")); } } Other vmod_cookie examples

vcl 4.0; import cookie; sub vcl_recv { cookie.parse(req.http.cookie); if(cookie.isset(“PHPSESSID") &&
req.url ~ "^/products/[0-9]+$") { cookie.delete("PHPSESSID"); } set req.http.cookie = cookie.get_string(); } Other vmod_cookie examples

https://github.com/varnish/varnish- modules/blob/master/docs/ vmod_cookie.rst

vmod_accept

https://github.com/gquintard/libvmod-accept

vcl 4.0; import accept; backend default { .host = "nginx";
.port = "80"; } sub vcl_init { new rule = accept.rule("en"); rule.add("nl"); } sub vcl_recv { set req.http.x-old-accept-language= req.http.Accept-Language; set req.http.Accept-Language = rule.filter(req.http.Accept-Language); return(synth(200,"<ul><li>Raw Accept-Language: "+req.http.x-old-accept- language+"</li><li>Filtered Accept-Language: "+req.http.Accept-Language+"</li></ ul>")); } vmod_accept

• Raw Accept-Language: nl,en-US;q=0.8,en;q=0.6 • Filtered Accept-Language: nl vmod_accept output

vcl 4.0; import accept; backend default { .host = "nginx";
.port = "80"; } sub vcl_init { new language = accept.rule("en"); language.add("nl"); new encoding = accept.rule("deflate"); language.add("gzip"); new contenttype = accept.rule("text/plain"); contenttype.add("text/html"); contenttype.add("application/json"); } sub vcl_recv { set req.http.Accept-Language = language.filter(req.http.Accept-Language); set req.http.Accept-Encoding = encoding.filter(req.http.Accept-Encoding); set req.http.Accept = contenttype.filter(req.http.Accept); } vmod_accept

Why is this useful?

Accept-Language: nl,en-US;q=0.8,en;q=0.6 Too many variations Impacts hit rate Why is
vmod_accept useful? Accept-Language: nl Less variations

More VMODs coming up later

In an ideal world

HTTP best practices > custom VCL

Reality sucks

Don’t trust the end-user

Cache-control ?

Legacy

Write VCL

Normalize

vcl 4.0; import accept; import std; backend default { .host
= "nginx"; .port = "80"; } sub vcl_init { new language = accept.rule("en"); language.add("nl"); new encoding = accept.rule(""); language.add("deflate"); language.add("gzip"); new contenttype = accept.rule("text/plain"); contenttype.add("text/html"); contenttype.add("application/json"); } sub vcl_recv { set req.http.Accept-Language = language.filter(req.http.Accept-Language); set req.http.Accept-Encoding = encoding.filter(req.http.Accept-Encoding); set req.http.Accept = contenttype.filter(req.http.Accept); if (req.http.User-Agent ~ "MSIE 6" || req.http.Accept-Encoding ~ "^\s*$") { unset req.http.Accept-Encoding; } set req.http.Host = regsub(req.http.Host, ":[0-9]+", ""); set req.url = std.querysort(req.url); Normalize

if (req.url ~ "(\?|&)(utm_source|utm_medium|utm_campaign|utm_content|gclid|cx|ie|cof|siteurl)=") { set req.url = regsuball(req.url, "&(utm_source|utm_medium|utm_campaign|utm_content|gclid|cx|ie|cof|
siteurl)=([A-z0-9_\-\.%25]+)", ""); set req.url = regsuball(req.url, "\?(utm_source|utm_medium|utm_campaign|utm_content|gclid|cx|ie|cof| siteurl)=([A-z0-9_\-\.%25]+)", "?"); set req.url = regsub(req.url, "\?&", "?"); set req.url = regsub(req.url, "\?$", ""); } if (req.url ~ "\#") { set req.url = regsub(req.url, "\#.*$", ""); } if (req.url ~ "\?$") { set req.url = regsub(req.url, "\?$", ""); } } Normalize

Static assets

vcl 4.0; sub vcl_recv { if (req.url ~ "^[^?]*\.(7z|avi|bmp|bz2|css|csv|doc|docx|eot|flac|flv| gif|gz|ico|jpeg|jpg|js|less|mka|mkv|mov|mp3|mp4|mpeg|mpg|odt|otf|ogg|
ogm|opus|pdf|png|ppt|pptx|rar|rtf|svg|svgz|swf|tar|tbz|tgz|ttf|txt|txz| wav|webm|webp|woff|woff2|xls|xlsx|xml|xz|zip)(\?.*)?$") { unset req.http.Cookie; return (hash); } } sub vcl_backend_response { if (bereq.url ~ "^[^?]*\.(7z|avi|bmp|bz2|css|csv|doc|docx|eot|flac| flv|gif|gz|ico|jpeg|jpg|js|less|mka|mkv|mov|mp3|mp4|mpeg|mpg|odt|otf| ogg|ogm|opus|pdf|png|ppt|pptx|rar|rtf|svg|svgz|swf|tar|tbz|tgz|ttf|txt| txz|wav|webm|webp|woff|woff2|xls|xlsx|xml|xz|zip)(\?.*)?$") { unset beresp.http.set-cookie; } if (bereq.url ~ "^[^?]*\.(7z|avi|bz2|flac|flv|gz|mka|mkv|mov|mp3|mp4| mpeg|mpg|ogg|ogm|opus|rar|tar|tgz|tbz|txz|wav|webm|xz|zip)(\?.*)?$") { unset beresp.http.set-cookie; set beresp.do_stream = true; set beresp.do_gzip = false; } } Cache static assets

Do you really want to cache static assets?

Nginx or Apache can be fast enough for that

vcl 4.0; import std; sub vcl_recv { if (req.url ~
"^[^?]*\.(7z|avi|bmp|bz2|css|csv|doc|docx|eot|flac|flv| gif|gz|ico|jpeg|jpg|js|less|mka|mkv|mov|mp3|mp4|mpeg|mpg|odt|otf|ogg| ogm|opus|pdf|png|ppt|pptx|rar|rtf|svg|svgz|swf|tar|tbz|tgz|ttf|txt|txz| wav|webm|webp|woff|woff2|xls|xlsx|xml|xz|zip)(\?.*)?$") { unset req.http.Cookie; return (pass); } } Don’t cache static assets

URL whitelist/blacklist

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

sub vcl_recv { if (req.url ~ "^/products/?" return (hash); }
} URL whitelist

Those damn cookies again!

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

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

vcl 4.0; sub vcl_recv { if (req.http.cookie) { cookie.parse(req.http.cookie); cookie.filter_except("PHPSESSID");
set req.http.cookie = cookie.get_string(); if (req.http.cookie ~ "^\s*$") { unset req.http.cookie; } } } The VMOD way

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

vcl 4.0; import cookie; backend default { .host = "nginx";
.port = "80"; } sub vcl_recv { if (req.http.cookie) { cookie.parse(req.http.cookie); cookie.filter_except("language"); set req.http.cookie = cookie.get_string(); if (req.http.cookie ~ "^\s*$") { unset req.http.cookie; } return(hash); } } sub vcl_hash { hash_data(cookie.get("language")); } The VMOD way

Alternative language cache variation

sub vcl_hash { hash_data(req.http.Accept-Language); } Language cookie cache variation Or
just send a “Vary:Accept-Language” header

sub vcl_recv { return(hash); } Cache, even with cookies

sub vcl_hash { hash_data(req.http.Cookie); } Hash all cookies

Block caching

Code renders single HTTP response

Lowest denominator: no cache

<esi:include src="/header" /> Edge Side Includes ✓Placeholder ✓Parsed by Varnish
✓Output is a composition of blocks ✓State per block ✓TTL per block

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

<?php header("Cache-Control: public,must-revalidate,s-maxage=10"); echo "Date in the ESI tag: ".date('Y-m-d
H:i:s').'<br />'; <?php header("Cache-Control: no-store"); header(“Surrogate-Control: content='ESI/1.0'"); echo '<esi:include src="/esi.php" />'.PHP_EOL; echo "Date in the main page: ".date('Y-m-d H:i:s').'<br />'; Main page ESI frame: esi.php Cached for 10 seconds Not cached

ESI_xmlerror No ESI processing, first char not '<'. (See feature
esi_disable_xml_check) Expects HTML/ XML tags

-p feature=+esi_disable_xml_check Add as startup option

req_top Get information about parent request in an ESI call

vcl 4.0; backend default { .host = "nginx"; .port =
"80"; } sub vcl_recv { if (req.esi_level > 0) { set req.http.x-parent-url = req_top.url; } } sub vcl_backend_response { if (beresp.http.Surrogate-Control ~ "ESI/1.0") { unset beresp.http.Surrogate-Control; set beresp.do_esi = true; } } Get parent URL

ESI vs AJAX

✓ Server-side ✓ Standardized ✓ Processed on the “edge”, no
in the browser ✓ Generally faster Edge-Side Includes - Sequential - One fails, all fail - Limited implementation in Varnish

✓ Client-side ✓ Common knowledge ✓ Parallel processing ✓ Graceful
degradation AJAX - Processed by the browser - Extra roundtrips - Somewhat slower

Choose wisely

Assemble at the view layer

{{ render_esi(controller('AppBundle:News:latest', { 'maxPerPage': 5 })) }} {{ render_esi(url('latest_news', {
'maxPerPage': 5 })) }} In your Twig templates Silex or Symfony Falls back to internal subrequests on failure Does ESI

{{ render_hinclude(controller('AppBundle:News:latest', { 'maxPerPage': 5 })) }} {{ render_hinclude(url(‘latest_news', {
'maxPerPage': 5 })) }} In your Twig templates Silex or Symfony Requires hinclude.js Does AJAX

<esi:include src="/header" /> ESI vs HInclude <hx:include src="/header"></hx:include> <meta name="include_timeout"
content="2" /> <meta name="include_mode" content="async" /> Extra parameters

Silex example

<?php use Symfony\Component\HttpFoundation\Response; require_once dirname(__DIR__).'/vendor/autoload.php'; $app = new Silex\Application(); $app['debug']
= true; $app->register(new Silex\Provider\TwigServiceProvider(), [ 'twig.path' => dirname(__DIR__).'/views' ]); $app->register(new Silex\Provider\HttpCacheServiceProvider()); $app->register(new Silex\Provider\HttpFragmentServiceProvider()); $app->get('/', function() use($app) { $response = new Response($app['twig']->render('index.twig')); $response->setSharedMaxAge(10); return $response; }); $app->get('/header', function() use($app) { $response = new Response($app['twig']->render('header.twig')); $response->setPrivate(); return $response; })->bind('header'); $app->get('/footer', function() use($app) { $response = new Response($app['twig']->render('footer.twig')); $response->setSharedMaxAge(3); return $response; })->bind('footer'); $app->run();

<!doctype html> <html> <body> {{ render_esi(url('header')) }} <h1>Main content</h1> <dl
class="row"> <dt class="col-sm-3">Date and time</dt> <dd class="col-sm-9">{{ "now"|date("m/d/Y H:i:s") }}</dd> </dl> {{ render_hinclude(url('footer')) }} <script src="https://rawgit.com/mnot/hinclude/master/hinclude.js"></ script> </body> </html> index.twig

<h1>Header</h1> <dl class="row"> <dt class="col-sm-3">Date and time</dt> <dd class="col-sm-9">{{ "now"|date("m/d/Y
H:i:s") }}</dd> </dl> <hr /> header.twig

<hr /> <h1>Footer</h1> <dl class="row"> <dt class="col-sm-3">Date and time</dt> <dd
class="col-sm-9">{{ "now"|date("m/d/Y H:i:s") }}</dd> </dl> footer.twig

Control Time To Live

sub vcl_backend_response { set beresp.ttl = 3h; } Control Time
To Live

sub vcl_backend_response { if (beresp.ttl <= 0s || beresp.http.Set-Cookie ||
beresp.http.Vary == "*") { set beresp.ttl = 120s; set beresp.uncacheable = true; return (deliver); } } Control Time To Live

Debugging

sub vcl_deliver { if (obj.hits > 0) { set resp.http.X-Cache
= "HIT"; } else { set resp.http.X-Cache = "MISS"; } } Debugging

Anonymize

sub vcl_deliver { unset resp.http.X-Powered-By; unset resp.http.Server; unset resp.http.X-Drupal-Cache; unset
resp.http.X-Varnish; unset resp.http.Via; unset resp.http.Link; unset resp.http.X-Generator; } Anonymize

Breaking news isn't breaking

Purging

acl purgers { "localhost"; "127.0.0.1"; "::1"; } sub vcl_recv {
if (req.method == "PURGE") { if (client.ip !~ purgers) { return (synth(405, "Method not allowed")); } return (purge); } } Purging

Purging curl -XPURGE "http://example.com/products" Immediately remove from memory

<?php header('Cache-control: no-cache'); $curl = curl_init('http://localhost/'); curl_setopt_array($curl,[ CURLOPT_RETURNTRANSFER => true,
CURLOPT_CUSTOMREQUEST => 'PURGE' ]); echo curl_exec($curl).PHP_EOL; Purging

<?php header('Cache-control: no-cache'); require 'guzzle.phar'; $client = new GuzzleHttp\Client(['base_uri' =>
'http://localhost:6081/']); $response = $client->request('PURGE', '/'); if($response->getStatusCode() == 200) { echo "PURGED".PHP_EOL; } else { echo $response->getBody(); } Purging

acl purge { "localhost"; "127.0.0.1"; "::1"; } sub vcl_recv {
if (req.method == "PURGE") { if (client.ip !~ purgers) { return (synth(405, "Method not allowed")); } if(req.http.x-purge-regex) { ban("req.http.host == " + req.http.host + " && req.url ~ " + req.http.x-purge-regex); } else { ban("req.http.host == " + req.http.host + " && req.url == " + req.url); } return (synth(200, "Purged")); } } Banning

Banning curl -XPURGE "http://example.com/products" curl -XPURGE -H "x-purge-regex:/products" "http://example.com" Add
to ban list, remove on next request Remove patterns via “X-PURGE-REGEX”

Lurker-friendly bans

Ban lurker Object User Varnish Server Sends HTTP response Response
stored in object Sends BAN to Varnish Ban lurker thread Ban list Reads ban list Removes object ban req.http.host == localhost && req.url ~ /products

Ban lurker ban req.http.host == localhost && req.url ~ /products
Lurker can’t match request info Lurker can only match what’s in the object Next visitor triggers cache remove

acl purge { "localhost"; "127.0.0.1"; "::1"; } sub vcl_recv {
if (req.method == "PURGE") { if (client.ip !~ purgers) { return (synth(405, "Method 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.host == " + req.http.host + " && obj.http.x-url == " + req.url); } return (synth(200, "Purged")); } } 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; } Lurker-friendly bans Store request info in response object

Lurker-friendly bans ban obj.http.x-host == localhost && obj.http.x-url ~ /products
Lurker can match response info Ban lurker removes item from cache async

varnish> param.show ban_lurker_age 200 ban_lurker_age Value is: 60.000 [seconds] (default)
Minimum is: 0.000 The ban lurker will ignore bans until they are this old. When a ban is added, the active traffic will be tested against it as part of object lookup. Because many applications issue bans in bursts, this parameter holds the ban-lurker off until the rush is over. This should be set to the approximate time which a ban-burst takes.

Banning through Varnishadm

varnishadm> ban obj.http.x-host == localhost && obj.http.x-url ~ /products Varnishadm
banning

Banning through socket

Varnishadm is a binary on top of the socket

Varnishadm uses the secret file to authenticate automatically

$ telnet varnish 6082 Connected to localhost. Escape character is
'^]'. 107 59 cohvooigdtqvkpwewhdxkqiwkfkpwsly Authentication required. auth 5a9c5722f31cc3c92f0e4616571624df7bddde2f8e42aaffe795dc80fb8c91dd 200 240 ----------------------------- Varnish Cache CLI 1.0 ----------------------------- Linux,4.9.49-moby,x86_64,-junix,-smalloc,-smalloc,-hcritbit varnish-5.2.0 revision 4c4875cbf Type 'help' for command list. Type 'quit' to close CLI session. ban obj.http.x-host == localhost && obj.http.x-url ~ /products 200 0

<?php $challenge = $argv[1]; $secret = trim(fgets(STDIN)); $pack = $challenge
. "\x0A" . $secret . "\x0A" . $challenge . "\x0A"; $key = hash('sha256', $pack); echo $key.PHP_EOL; Use secret & process challenge cohvooigdtqvkpwewhdxkqiwkfkpwsly 5a9c5722f31cc3c92f0e4616571624df7bddde2f8e42aaffe795dc80fb8c91dd E29F6DE6-3803-449E-8A01-AA537A8715B1

$ telnet varnish 6082 Connected to localhost. Escape character is
'^]'. 107 59 cohvooigdtqvkpwewhdxkqiwkfkpwsly Authentication required. auth 5a9c5722f31cc3c92f0e4616571624df7bddde2f8e42aaffe795dc80fb8c91dd 200 240 ----------------------------- Varnish Cache CLI 1.0 ----------------------------- Linux,4.9.49-moby,x86_64,-junix,-smalloc,-smalloc,-hcritbit varnish-5.2.0 revision 4c4875cbf Type 'help' for command list. Type 'quit' to close CLI session. ban obj.http.x-host == localhost && obj.http.x-url ~ /products 200 0

Secure your access the the admin socket

DAEMON_OPTS="-j unix,user=www-data \ -a :80 \ -a :81,PROXY \ -T

Admin socket does more than banning

----------------------------- Varnish Cache CLI 1.0 ----------------------------- Linux,4.9.49-moby,x86_64,-junix,-smalloc,-smalloc,-hcritbit varnish-5.2.0 revision 4c4875cbf
Type 'help' for command list. Type 'quit' to close CLI session. help 200 613 auth <response> backend.list [-p] [<backend_pattern>] backend.set_health <backend_pattern> [auto|healthy|sick] ban <field> <operator> <arg> [&& <field> <oper> <arg> ...] ban.list banner help [<command>] panic.clear [-z] panic.show param.set <param> <value> param.show [-l] [<param>] ping [<timestamp>] quit start status stop storage.list vcl.discard <configname|label> vcl.inline <configname> <quoted_VCLstring> [auto|cold|warm] vcl.label <label> <configname> vcl.list vcl.load <configname> <filename> [auto|cold|warm] vcl.show [-v] <configname> vcl.state <configname> [auto|cold|warm] vcl.use <configname|label>

Refresh content

vcl 4.0; acl refreshers { "172.18.0.0"/24; "localhost"; } backend default
{ .host = "nginx"; .port = "80"; } sub vcl_recv { if (req.method == "REFRESH") { if (client.ip !~ refreshers) { return (synth(405, "Method not allowed")); } set req.method = "GET"; set req.hash_always_miss = true; } } Refresh content Perform miss, fetch content, overwrite object

Refresh content curl -XREFRESH "http://example.com/products"

Tag-base invalidation

vmod_xkey

vcl 4.0; import xkey; acl purgers { "172.18.0.0"/24; } backend
default { .host = "nginx"; .port = "80"; } sub vcl_recv { if (req.method == "PURGE") { if (client.ip !~ purgers) { return (synth(405, "Method now allowed")); } set req.http.n-gone = xkey.purge(req.http.key); return (synth(200, "Invalidated "+req.http.n-gone+" objects for key "+ req.http.key)); } if (req.method == "SOFTPURGE") { if (client.ip !~ purgers) { return (synth(405, "Method not allowed")); } set req.http.n-gone = xkey.softpurge(req.http.key); return (synth(200, "Invalidated "+req.http.n-gone+" objects via softpurge for key "+ req.http.key)); } }

<?php header('Cache-control: public, s-maxage=100'); header("xkey: a"); header("xkey: b",false); echo date('Y-m-d
H:i:s').'<br />'.PHP_EOL; Add “xkey” headers Register tags

Invalidate tags curl -XPURGE -H"key: b" "http://example.com/" PURGE / HTTP/1.1
Host: localhost User-Agent: curl/7.55.1 Accept: */* key:b

Header-based invalidation

Header-based invalidation If-Modified-Since: Tue, 14 Jun 2016 11:49:18 GMT Last-Modified:
Tue, 14 Jun 2016 11:49:32 GMT Cache-Control: max-age=10 HTTP 200: OK HTTP 304: Not modified

Header-based invalidation If-None-Match: 57601698ae1e2 Etag: 57601698ae1e2 Cache-Control: max-age=10 HTTP 200:
OK HTTP 304: Not modified

Grace mode

beresp.grace Keep servering stale object while fetching data from backend
Avoid excessive request queueing

sub vcl_backend_response { set beresp.grace = 2h; } Grace

Cache-Control: public, max-age=100, s-maxage=3600, stale-while-revalidate=7200 Stale-While-Revalidate

sub vcl_backend_response { set beresp.grace = 6h; } Grace mode
Monitoring & logging

Varnishstat Realtime statistics

usage: varnishstat [-1lV] [-f field] [-t seconds|<off>] [-n varnish_name] [-N
filename] -1 # Print the statistics to stdout. -f field # Field inclusion glob # If it starts with '^' it is used as an exclusion list. -l # Lists the available fields to use with the -f option. -n varnish_name # The varnishd instance to get logs from. -N filename # Filename of a stale VSM instance. -t seconds|<off> # Timeout before returning error on initial VSM connection. -V # Display the version number and exit. -x # Print statistics to stdout as XML. -j # Print statistics to stdout as JSON. Varnishstat usage

~# varnishstat -f MAIN.cache_hit -1 MAIN.cache_hit 13049135 5.39 Cache hits
Varnishstat usage ~# varnishstat -f MAIN.cache_hit -j -1 { "timestamp": "2016-06-14T16:10:32", "MAIN.cache_hit": { "description": "Cache hits", "type": "MAIN", "flag": "c", "format": "i", "value": 13050992 } }

Varnishstat usage ~# varnishstat -f MAIN.n_object -f MAIN.n_lru_nuked -j {
"timestamp": "2016-06-14T16:14:49", "MAIN.n_object": { "description": "object structs made", "type": "MAIN", "flag": "g", "format": "i", "value": 46295 }, "MAIN.n_lru_nuked": { "description": "Number of LRU nuked objects", "type": "MAIN", "flag": "g", "format": "i", "value": 0 } }

varnishstat -f MAIN.cache*

✓ Session ✓ Client ✓ Uptime ✓ Hit/miss ✓ Backend
✓ Fetch ✓ Threading ✓ Cache objects ✓ Memory ✓ Invalidation Varnishstat counters

Varnish Shared memory Logging

✓ In-memory logs ✓ Generated by varnishd ✓ 81 MB
by default ✓ Customize with “-l” setting ✓ Varnishlog command ✓ Varnishtop command VSL

* << Request >> 10973258 - Begin req 10973257 rxreq
- Timestamp Start: 1501507281.942533 0.000000 0.000000 - Timestamp Req: 1501507281.942533 0.000000 0.000000 - ReqStart 127.0.0.1 59753 - ReqMethod GET - ReqURL / - ReqProtocol HTTP/1.1 - ReqHeader Host: feryn.eu

Transactions

✓ Items of work ✓ Identified by VXID ✓ 2
kinds: ✓ Sessions ✓ Requests Transactions

✓ Identifies TCP connection ✓ Contains multiple requests Transactions ✓
Client request ✓ Backend request ✓ ESI subrequest Session Request

✓ VXID (default) ✓ Session ✓ Request ✓ Raw Transactions
grouping

Example composition that will be monitored

varnishlog -i Begin,ReqUrl,Link,BereqURL

* << BeReq >> 98318 - Begin bereq 98317 fetch
- BereqURL / * << BeReq >> 98320 - Begin bereq 98319 fetch - BereqURL /header * << Request >> 98319 - Begin req 98317 esi - ReqURL /header - Link bereq 98320 fetch * << BeReq >> 98322 - Begin bereq 98321 fetch - BereqURL /nav * << Request >> 98321 - Begin req 98317 esi - ReqURL /nav - Link bereq 98322 fetch * << Request >> 98317 - Begin req 98316 rxreq - ReqURL / - Link bereq 98318 fetch - Link req 98319 esi - Link req 98321 esi * << BeReq >> 98324 - Begin bereq 98323 fetch - BereqURL /footer * << Request >> 98323 - Begin req 98316 rxreq - ReqURL /footer - Link bereq 98324 fetch * << Session >> 98316 - Begin sess 0 HTTP/1 - Link req 98317 rxreq - Link req 98323 rxreq

varnishlog -i Begin,ReqUrl,Link,BereqURL -g session

* << Session >> 14 - Begin sess 0 HTTP/1
- Link req 65539 rxreq - Link req 65545 rxreq ** << Request >> 65539 -- Begin req 14 rxreq -- ReqURL / -- Link bereq 65540 fetch -- Link req 65541 esi -- Link req 65543 esi ** << Request >> 65545 -- Begin req 14 rxreq -- ReqURL /footer -- Link bereq 65546 fetch *** << BeReq >> 65540 --- Begin bereq 65539 fetch --- BereqURL / *** << Request >> 65541 --- Begin req 65539 esi --- ReqURL /header --- Link bereq 65542 fetch *** << Request >> 65543 --- Begin req 65539 esi --- ReqURL /nav --- Link bereq 65544 fetch *** << BeReq >> 65546 --- Begin bereq 65545 fetch --- BereqURL /footer **** << BeReq >> 65542 ---- Begin bereq 65541 fetch ---- BereqURL /header **** << BeReq >> 65544 ---- Begin bereq 65543 fetch ---- BereqURL /nav

Request tags

✓ ReqMethod ✓ ReqUrl ✓ ReqProtocol ✓ ReqHeader Request tags

- ReqStart 127.0.0.1 56312 - ReqMethod GET - ReqURL /
- ReqProtocol HTTP/1.1 - ReqHeader Host: localhost - ReqHeader Connection: keep-alive - ReqHeader Upgrade-Insecure-Requests: 1 - ReqHeader User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/ 59.0.3071.115 Safari/537.36 - ReqHeader Accept: text/html,application/xhtml+xml,application/ xml;q=0.9,image/webp,image/apng,*/*;q=0.8 - ReqHeader Accept-Encoding: gzip, deflate, br - ReqHeader Accept-Language: nl,en-US;q=0.8,en;q=0.6 - ReqHeader X-Forwarded-For: 127.0.0.1

Response tags

✓ RespProtocol ✓ RespStatus ✓ RespReason ✓ RespHeader Response tags

- RespProtocol HTTP/1.1 - RespStatus 200 - RespReason OK -
RespHeader Host: localhost - RespHeader Cache-Control: public, s-maxage=500 - RespHeader Date: Tue, 01 Aug 2017 08:56:44 GMT - RespHeader ETag: "c5afddc587599a72d467caca23e980bf" - RespHeader Vary: Accept-Language - RespHeader Content-Length: 3098 - RespHeader Content-Type: text/html; charset=UTF-8 - RespHeader X-Varnish: 32770 - RespHeader Age: 10

Backend tags

- BackendOpen 19 boot.default 127.0.0.1 8080 127.0.0.1 62552 - BackendClose
19 boot.default

Backend request tags

✓ BereqMethod ✓ BereqUrl ✓ BereqProtocol ✓ BereqHeader Backend request
tags

Backend response tags

✓ BerespProtocol ✓ BerespStatus ✓ BerespReason ✓ BerespHeader Backens response
tags

Object tags

✓ ObjProtocol ✓ ObjStatus ✓ ObjReason ✓ ObjHeader Object tags

VCL tags

✓ VCL_Call ✓ VCL_Return ✓ VCL_Error ✓ VCL_Log ✓ VCL_Acl
VCL tags

* << Request >> 5 - ReqURL / - VCL_call
RECV - VCL_return hash - VCL_call HASH - VCL_return lookup - VCL_call MISS - VCL_return fetch - VCL_call DELIVER - VCL_return deliver ** << BeReq >> 6 -- BereqURL / -- VCL_call BACKEND_FETCH -- VCL_return fetch -- VCL_call BACKEND_RESPONSE -- VCL_return deliver

* << Request >> 6 - ReqURL / - VCL_call
RECV - ReqURL / - VCL_return hash - VCL_call HASH - VCL_return lookup - VCL_call HIT - VCL_return deliver - VCL_call DELIVER - VCL_return deliver

* << Request >> 32789 - ReqURL /header - ExpBan
98355 banned lookup ExpBan tag

* << Request >> 98369 - ReqURL /footer - Hit
65597 Hit tag varnishlog -i "ReqUrl,Hit"

** << Request >> 6 -- ReqURL /footer -- HitPass
3 HitPass tag

TTL tag

-- TTL VCL 120 10 0 1501597242 ✓ TTL decided
by the VCL ✓ 120 seconds cached ✓ 10 seconds grace time ✓ 0 seconds keep time ✓ Reference time: 1501597242  (2017-08-01 14:20:42)

-- RFC 500 10 -1 1501598872 1501598872 1501598872 0 500
✓ 500 seconds TTL (via headers) ✓ 10 seconds grace ✓ No keep value ✓ 2017-08-01 14:47:52 date, age & reference time ✓ Cache-control headers sets 500 second TTL

-- RFC 500 10 -1 1501598872 1501598869 1501598872 0 500
✓ Don’t screw with the age header ✓ Only 497 second effective TTL ✓ Custom Age header (3 seconds off)

Begin tag

- Begin bereq 98317 fetch - Begin req 98317 esi
- Begin req 98316 rxreq - Begin sess 0 HTTP/1

Link tag

- Link bereq 98312 fetch - Link req 98311 rxreq
- Link req 98318 esi

Timestamp tag

* << Request >> 65539 - Timestamp Start: 1501601912.758662 0.000000
0.000000 - Timestamp Req: 1501601912.758662 0.000000 0.000000 - Timestamp Fetch: 1501601912.806733 0.048071 0.048071 - Timestamp Process: 1501601912.806750 0.048088 0.000017 - Timestamp Resp: 1501601912.806787 0.048125 0.000037 ** << BeReq >> 65540 -- Timestamp Start: 1501601912.758753 0.000000 0.000000 -- Timestamp Bereq: 1501601912.758952 0.000199 0.000199 -- Timestamp Beresp: 1501601912.806677 0.047924 0.047725 -- Timestamp BerespBody: 1501601912.806749 0.047996 0.000072

Filtering output

✓ -i: include tags ✓ -I: include tags by regex
✓ -x: exclude tags ✓ -X: exclude by regex Filtering output

Include tags

varnishlog -i ReqUrl,VCL_call,VCL_return -g session varnishlog -i "ReqUrl,VCL_*" -g session

* << Session >> 252394 ** << Request >> 252395
-- ReqURL / -- VCL_call RECV -- VCL_return hash -- VCL_call HASH -- VCL_return lookup -- VCL_call HIT -- VCL_return deliver -- VCL_call DELIVER -- VCL_return deliver *** << Request >> 252397 --- ReqURL /header --- VCL_call RECV --- VCL_return hash --- VCL_call HASH --- VCL_return lookup --- VCL_call HIT --- VCL_return deliver --- VCL_call DELIVER --- VCL_return deliver *** << Request >> 252399 --- ReqURL /nav --- VCL_call RECV --- VCL_return hash --- VCL_call HASH --- VCL_return lookup --- VCL_call HIT --- VCL_return deliver --- VCL_call DELIVER --- VCL_return deliver *** << BeReq >> 252396 --- VCL_call BACKEND_FETCH --- VCL_return fetch --- VCL_call BACKEND_RESPONSE --- VCL_return deliver **** << BeReq >> 252398 ---- VCL_call BACKEND_FETCH ---- VCL_return fetch ---- VCL_call BACKEND_RESPONSE ---- VCL_return deliver **** << BeReq >> 252400 ---- VCL_call BACKEND_FETCH ---- VCL_return fetch ---- VCL_call BACKEND_RESPONSE ---- VCL_return deliver

Exclude tags

varnishlog -i "Req*" -x ReqHeader,ReqUnset

* << Request >> 314125 - ReqStart 127.0.0.1 64585 -
ReqMethod GET - ReqURL / - ReqProtocol HTTP/1.1 - ReqAcct 476 0 476 311 0 311 * << Request >> 314126 - ReqStart 127.0.0.1 64585 - ReqMethod GET - ReqURL /footer - ReqProtocol HTTP/1.1 - ReqAcct 370 0 370 309 0 309

Include tags by regex

varnishlog -I "reqheader:Accept-Language" -i requrl

* << Request >> 374378 - ReqURL / - ReqHeader
Accept-Language: nl,en-US;q=0.8,en;q=0.6 * << Request >> 374379 - ReqURL /footer - ReqHeader Accept-Language: nl,en-US;q=0.8,en;q=0.6

Exclude tags by regex

* << Request >> 374384 - ReqURL /footer - RespHeader
Host: localhost - RespHeader X-Powered-By: PHP/7.0.15 - RespHeader Cache-Control: public, s-maxage=500 - RespHeader Date: Wed, 02 Aug 2017 11:27:21 GMT - RespHeader ETag: "d47ac09f5351f8f4c97c99ef5b3d2ecd" - RespHeader Vary: Accept-Language - RespHeader Content-Length: 80 - RespHeader Content-Type: text/html; charset=UTF-8 - RespHeader X-Varnish: 374384 15367 - RespHeader Age: 334 - RespHeader Via: 1.1 varnish-v4 - RespHeader Connection: keep-alive

varnishlog -i RespHeader,ReqUrl -X "RespHeader:(x|X)-"

* << Request >> 374384 - ReqURL /footer - RespHeader
Host: localhost - RespHeader Cache-Control: public, s-maxage=500 - RespHeader Date: Wed, 02 Aug 2017 11:27:21 GMT - RespHeader ETag: "d47ac09f5351f8f4c97c99ef5b3d2ecd" - RespHeader Vary: Accept-Language - RespHeader Content-Length: 80 - RespHeader Content-Type: text/html; charset=UTF-8 - RespHeader Age: 334 - RespHeader Via: 1.1 varnish-v4 - RespHeader Connection: keep-alive

All-in-one

varnishlog -i "RespHeader,Req*" -X "RespHeader:(x|X)-" -I "timestamp:Resp" -x reqprotocol,reqacct -g
request

* << Request >> 59383 - ReqStart 127.0.0.1 53195 -
ReqMethod GET - ReqURL / - ReqHeader Host: localhost - ReqHeader Connection: keep-alive - ReqHeader Cache-Control: max-age=0 - ReqHeader Upgrade-Insecure-Requests: 1 - ReqHeader User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36 - ReqHeader Accept: text/ html,application/ xhtml+xml,application/xml;q=0.9,image/ webp,image/apng,*/*;q=0.8 - ReqHeader Accept-Encoding: gzip, deflate, br - ReqHeader Accept-Language: nl,en- US;q=0.8,en;q=0.6 - ReqHeader If-None-Match: W/"27f341f8e459dd35f1087c55351cacda" - ReqHeader X-Forwarded-For: 127.0.0.1 - ReqUnset Accept-Language: nl,en- US;q=0.8,en;q=0.6 - ReqHeader accept-language: nl - ReqHeader Surrogate-Capability: key=ESI/1.0 - ReqUnset Accept-Encoding: gzip, deflate, br - ReqHeader Accept-Encoding: gzip - RespHeader Host: localhost - RespHeader Cache-Control: public, s- maxage=500 - RespHeader Date: Wed, 02 Aug 2017 11:46:49 GMT - RespHeader ETag: "27f341f8e459dd35f1087c55351cacda" - RespHeader Vary: Accept-Language - RespHeader Content-Length: 3098 - RespHeader Content-Type: text/html; charset=UTF-8 - RespHeader Age: 152 - RespHeader Via: 1.1 varnish-v4 - RespHeader ETag: W/"27f341f8e459dd35f1087c55351cacda" - RespHeader Connection: keep-alive - Timestamp Resp: 1501674561.472358 0.000068 0.000020

✓ All response headers ✓ All tags that start with
“Req” ✓ Exclude “x-“ response headers ✓ Include “response time” timestamp ✓ Exclude request protocol log lines, and the request accountancy log lines All-in-one

VSL queries

Filtering fields from all transactions Filtering transactions

<record selection criteria> <operator> <operand> {level}taglist:record-prefix[field]

ReqUrl eq ‘/‘ {level}taglist:record-prefix[field]

Timestamp:Resp[2] > 1.0 {level}taglist:record-prefix[field]

{2}Timestamp:Resp[2] > 1.0 {level}taglist:record-prefix[field]

varnishlog -i VCL_call,VCL_return -g request -q "ReqURL eq '/'"

* << Request >> 374400 - VCL_call RECV - VCL_return
hash - VCL_call HASH - VCL_return lookup - VCL_call HIT - VCL_return deliver - VCL_call DELIVER - VCL_return deliver

varnishlog -i ReqUrl -q "VCL_call eq 'MISS' or VCL_call eq
'PASS'" varnishlog -i ReqUrl -I "Timestamp:Resp" -q "Timestamp:Resp[2] > 1.0"

Other options

varnishlog -n myVarnishInstance varnishlog -d varnishlog -w file varnishlog -r
file varnishlog -A -a -w file varnishlog -i "ReqUrl,VCL_*" -D -a -A -w /var/log/varnish/custom.log - P /var/run/custom_varnishlog.pid

Varnishtop

Same syntax as varnishlog. Output is incremental

$ varnishtop -I reqheader:Accept-Language -q "ReqUrl eq '/'" list length
4 0.86 ReqHeader Accept-Language: en-US 0.80 ReqHeader Accept-Language: nl-NL,nl;q=0.8,en- US;q=0.6,en;q=0.4 0.54 ReqHeader Accept-Language: nl,en-US;q=0.8,en;q=0.6 0.39 ReqHeader Accept-Language: nl-BE

Common Varnishlog scenarios

Why didn’t Varnish serve this request from cache?

Request not cacheable

varnishlog -i "Req*,VCL*" -x ReqAcct,ReqStart -q "VCL_call eq 'PASS'"

* << Request >> 12 - ReqMethod GET - ReqURL
/ - ReqProtocol HTTP/1.1 - ReqHeader Host: localhost - ReqHeader User-Agent: curl/7.48.0 - ReqHeader Accept: */* - ReqHeader Cookie: myCookie=bla - ReqHeader X-Forwarded-For: 127.0.0.1 - VCL_call RECV - VCL_return pass - VCL_call HASH - VCL_return lookup - VCL_call PASS - VCL_return fetch - VCL_call DELIVER - VCL_return deliver

<< Request >> 32779 - ReqMethod POST - ReqURL /
- ReqProtocol HTTP/1.1 - ReqHeader Host: localhost - ReqHeader User-Agent: curl/7.48.0 - ReqHeader Accept: */* - ReqHeader X-Forwarded-For: 127.0.0.1 - VCL_call RECV - VCL_return pass - VCL_call HASH - VCL_return lookup - VCL_call PASS - VCL_return fetch - VCL_call DELIVER - VCL_return deliver

* << Request >> 15 - ReqMethod GET - ReqURL
/ - ReqProtocol HTTP/1.1 - ReqHeader Host: localhost - ReqHeader Authorization: Basic dGhpanM6ZmVyeW4= - ReqHeader User-Agent: curl/7.48.0 - ReqHeader Accept: */* - ReqHeader X-Forwarded-For: 127.0.0.1 - VCL_call RECV - VCL_return pass - VCL_call HASH - VCL_return lookup - VCL_call PASS - VCL_return fetch - VCL_call DELIVER - VCL_return deliver

Response not cacheable

varnishlog -i ReqUrl,VCL_*,Beresp*,TTL -q "HitPass" -g request

* << Request >> 19010384 - ReqURL /my-url - VCL_call
RECV - VCL_return hash - VCL_call HASH - VCL_return lookup - VCL_call PASS - VCL_return fetch - VCL_call DELIVER - VCL_return deliver ** << BeReq >> 19010385 -- VCL_call BACKEND_FETCH -- VCL_return fetch -- BerespProtocol HTTP/1.1 -- BerespStatus 200 -- BerespReason OK -- BerespHeader Date: Thu, 03 Aug 2017 08:15:22 GMT -- BerespHeader Server: Apache/ 2.4.10 (Debian) -- BerespHeader Last-Modified: Tue, 01 Aug 2017 07:21:00 GMT -- BerespHeader ETag: "5c0d-555abfd3f422f-gzip" -- BerespHeader Vary: Accept- Encoding -- BerespHeader Content-Encoding: gzip -- BerespHeader Cache-Control: maxage=0 -- BerespHeader Expires: Thu, 03 Aug 2017 08:15:22 GMT -- BerespHeader Content-Length: 7686 -- BerespHeader Content-Type: application/json -- TTL RFC 0 10 -1 1501748123 1501748123 1501748122 1501748122 0 -- VCL_call BACKEND_RESPONSE -- TTL VCL 120 10 0 1501748123 -- VCL_return deliver

* << Request >> 65551 - ReqURL /set-cookie - VCL_call
RECV - VCL_return hash - VCL_call HASH - VCL_return lookup - VCL_call PASS - VCL_return fetch - VCL_call DELIVER - VCL_return deliver ** << BeReq >> 65552 -- VCL_call BACKEND_FETCH -- VCL_return fetch -- BerespProtocol HTTP/1.1 -- BerespStatus 200 -- BerespReason OK -- BerespHeader Cache-control: s-maxage=10 -- BerespHeader Set-Cookie: myCookie=bla -- BerespHeader Content-type: text/html; charset=UTF-8 -- BerespHeader Date: Thu, 03 Aug 2017 08:39:04 GMT -- TTL RFC 10 10 -1 1501749545 1501749545 1501749544 0 10 -- VCL_call BACKEND_RESPONSE -- TTL VCL 120 10 0 1501749545 -- VCL_return deliver

Authentication

Authorization: Basic QWxhZGRpbjpPcGVuU2VzYW1l

PHPSESSID: laken37oumlkrndoo91k3trlv5

vcl 4.0; sub vcl_recv { if (req.method == "PRI") {
return (synth(405)); } if (req.method != "GET" && req.method != "HEAD" && req.method != "PUT" && req.method != "POST" && req.method != "TRACE" && req.method != "OPTIONS" && req.method != “PATCH" && req.method != "DELETE") { return (pipe); } if (req.method != "GET" && req.method != "HEAD") { return (pass); } if (req.http.Authorization || req.http.Cookie) { return (pass); } return (hash); }

What if we could create cache variations for logged-in users?

How do you identify a logged-in user without accessing the
backend every time?

Push session information from the server to the client

JSON Web Tokens

Marco Pivetta introduced me to JWT https://twitter.com/ocramius

JWT eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOi JodHRwOlwvXC9sb2NhbGhvc3RcLyIsImlhdCI6MTUwODc0N zM2MywiZXhwIjoxNTA4NzUwOTYzLCJ1aWQiOjEsInVzZXJu YW1lIjoiVGhpanMifQ.EPemqBaH74Sbs0bZqAaR8i7uVYO3 89VOlJvWC3ocL7g ✓3 parts ✓Dot separated
✓Base64 encoded JSON ✓Header ✓Payload ✓Signature (HMAC with secret)

eyJpc3MiOiJodHRwOlwvXC 9sb2NhbGhvc3RcLyIsImlh dCI6MTUwODc0NzM2MywiZX hwIjoxNTA4NzUwOTYzLCJ1 aWQiOjEsInVzZXJuYW1lIj oiVGhpanMifQ { "alg": "HS256", "typ":
"JWT" } { "iss": "http://localhost/", "iat": 1508746861, "exp": 1508750461, "uid": 1, "username": "Thijs" } HMACSHA256( base64UrlEncode(header) + "." + base64UrlEncode(payload), secret ) eyJ0eXAiOiJKV1QiLCJhb GciOiJIUzI1NiJ9 EPemqBaH74Sbs0bZqAaR8i 7uVYO389VOlJvWC3ocL7g

https://jwt.io

JWT Cookie:jwt_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9. eyJpc3MiOiJodHRwOlwvXC9sb2NhbGhvc3RcLyIsImlhdCI6MTUwOD c0NzM2MywiZXhwIjoxNTA4NzUwOTYzLCJ1aWQiOjEsInVzZXJuYW1l IjoiVGhpanMifQ.EPemqBaH74Sbs0bZqAaR8i7uVYO389VOlJvWC3o cL7g ✓Stored in a cookie
✓Can be validated by Varnish ✓Payload can be processed by any language (e.g. Javascript)

Application creates JWT alongside the regular session

Template loads stateful data from JWT in Javascript

{ "iss": "http://localhost/", "iat": 1508746861, "exp": 1508750461, "uid": 1, "username":
"Thijs" } Issuer

"Thijs" } Issued at

"Thijs" } Expires at

"Thijs" } User ID

"Thijs" } Username

"Thijs" } Let Javascript parse this one

User Varnish Server Issues JWT Validates JWT Reads JWT Knows
secret key Knows secret key Does not know secret key

Using vmod_digest for HMAC & base64

vcl 4.0; import std; import var; import cookie; import digest;
backend default { .host = "nginx"; .port = "80"; } sub vcl_recv { if (req.http.Cookie) { cookie.parse(req.http.cookie); cookie.filter_except("jwt_cookie"); set req.http.cookie = cookie.get_string(); if (req.http.Cookie ~ "^\s*$") { unset req.http.Cookie; } } if ((req.method != "GET" && req.method != "HEAD") || req.http.Authorization) { return (pass); } call jwt; return(hash); }

sub vcl_synth { #301 & 302 synths should be actual
redirects if (resp.status == 301 || resp.status == 302) { set resp.http.location = resp.reason; set resp.reason = "Moved"; return (deliver); } }

sub jwt { var.set("key",std.fileread("/etc/varnish/jwt.key")); std.log("Ready to perform some JWT magic");
if(cookie.isset("jwt_cookie")) { var.set("token", cookie.get("jwt_cookie")); var.set("header", regsub(var.get("token"),"([^\.]+)\.[^\.]+\.[^\.]+","\1")); var.set("type", regsub(digest.base64url_decode(var.get("header")),{"^.*?"typ"\s*: \s*"(\w+)".*?$"},"\1")); var.set("algorithm", regsub(digest.base64url_decode(var.get("header")), {"^.*?"alg"\s*:\s*"(\w+)".*?$"},"\1")); if(var.get("type") == "JWT" && var.get("algorithm") == "HS256") { var.set("rawPayload",regsub(var.get("token"),"[^\.]+\.([^\.]+)\.[^\.]+$","\1")); var.set("signature",regsub(var.get("token"),"^[^\.]+\.[^\.]+\.([^\.]+)$","\1")); var.set("currentSignature",digest.base64url_nopad_hex(digest.hmac_sha256(var.get("key"), var.get("header") + "." + var.get("rawPayload")))); var.set("payload", digest.base64url_decode(var.get("rawPayload"))); var.set("exp",regsub(var.get("payload"),{"^.*?"exp"\s*:\s*([0-9]+).*?$"},"\1")); var.set("userId",regsub(var.get("payload"),{"^.*?"uid"\s*:\s*([0-9]+).*? $"},"\1")); if(var.get("userId") ~ "^\d+$") { if(std.time(var.get("exp"),now) >= now) { if(var.get("signature") == var.get("currentSignature")) { set req.http.X-Login="true"; } else { std.log("JWT: signature doesn't match. Received: " + var.get("signature") + ", expected: " + var.get("currentSignature"));

var.set("header", regsub(var.get("token"),"([^\.]+)\.[^\.]+\.[^\.]+","\1")); First chunk contains the header

var.set("type", regsub(digest.base64url_decode(var.get("header")), {"^.*?"typ"\s*:\s*"(\w+)".*?$"},"\1")); Get type field from header

var.set("algorithm", regsub(digest.base64url_decode(var.get("header")), {"^.*?"alg"\s*:\s*"(\w+)".*?$"},"\1")); Get algorithm field from header

sub jwt { var.set("key",std.fileread("/etc/varnish/jwt.key")); std.log("Ready to perform some JWT magic");
if(cookie.isset("jwt_cookie")) { var.set("token", cookie.get("jwt_cookie")); var.set("header", regsub(var.get("token"),"([^\.]+)\.[^\.]+\.[^\.]+","\1")); var.set("type", regsub(digest.base64url_decode(var.get("header")),{"^.*?"typ"\s*: \s*"(\w+)".*?$"},"\1")); var.set("algorithm", regsub(digest.base64url_decode(var.get("header")), {"^.*?"alg"\s*:\s*"(\w+)".*?$"},"\1")); if(var.get("type") == "JWT" && var.get("algorithm") == "HS256") { var.set("rawPayload",regsub(var.get("token"),"[^\.]+\.([^\.]+)\.[^\.]+$","\1")); var.set("signature",regsub(var.get("token"),"^[^\.]+\.[^\.]+\.([^\.]+)$","\1")); var.set("currentSignature",digest.base64url_nopad_hex(digest.hmac_sha256(var.get("key"), var.get("header") + "." + var.get("rawPayload")))); var.set("payload", digest.base64url_decode(var.get("rawPayload"))); var.set("exp",regsub(var.get("payload"),{"^.*?"exp"\s*:\s*([0-9]+).*?$"},"\1")); var.set("userId",regsub(var.get("payload"),{"^.*?"uid"\s*:\s*([0-9]+).*? $"},"\1")); if(var.get("userId") ~ "^\d+$") { if(std.time(var.get("exp"),now) >= now) { if(var.get("signature") == var.get("currentSignature")) { set req.http.X-Login="true"; } else { std.log("JWT: signature doesn't match. Received: " + var.get("signature") + ", expected: " + var.get("currentSignature"));

var.set(“rawPayload",regsub(var.get("token"),"[^\.]+\.([^\.]+)\.[^\.]+ $","\1")); var.set("payload", digest.base64url_decode(var.get("rawPayload"))); Second chunk contains the raw payload
Base64 decode to get JSON payload

var.set("signature",regsub(var.get("token"),"^[^\.]+\.[^\.]+\.([^\.]+) $","\1")); var.set("currentSignature",digest.base64url_nopad_hex(digest.hmac_sha256(var .get("key"),var.get("header") + "." + var.get("rawPayload")))); Third chunk
contains the raw signature Build signature using key, header & payload

var.set("exp",regsub(var.get("payload"),{"^.*?"exp"\s*:\s*([0-9]+).*? $"},"\1")); var.set("userId",regsub(var.get("payload"),{"^.*?"uid"\s*:\s*([0-9]+).*? $"},"\1")); Extract expiration time from JSON payload
Extract user ID from JSON payload

var.get("header") + "." + var.get("rawPayload")))); var.set("payload", digest.base64url_decode(var.get("rawPayload"))); var.set("exp",regsub(var.get("payload"),{"^.*?"exp"\s*:\s*([0-9]+).*?$"},"\1")); var.set("userId",regsub(var.get("payload"),{"^.*?"uid"\s*:\s*([0-9]+).*? $"},"\1"));
if(var.get("userId") ~ "^\d+$") { if(std.time(var.get("exp"),now) >= now) { if(var.get("signature") == var.get("currentSignature")) { set req.http.X-Login="true"; } else { std.log("JWT: signature doesn't match. Received: " + var.get("signature") + ", expected: " + var.get("currentSignature")); } } else { std.log("JWT: token has expired"); } } else { std.log("UserId '"+ var.get("userId") +"', is not numeric"); } } else { std.log("JWT: type is not JWT or algorithm is not HS256"); } std.log("JWT processing finished. UserId: " + var.get("userId") + ". X-Login: " + req.http.X-login); } if(req.url ~ "^/(\?[^\?]+)?$" && req.http.X-Login != "true") { return(synth(302,"/post.php")); } }

Cache variations

Vary: X-Login Vary header sent by application X-Login header set
by Varnish Creates cache variations in Varnish

Write cacheable applications

✓ Cache-control ✓ Content negotiation ✓ Cache variations ✓ Conditional
requests ✓ Content composition ✓ JWT authentication Checklist

Let’s build a cacheable Symfony app

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