This document summarizes Varnishtest, a script-driven tool for testing Varnish configurations. It can define a Varnish server, backend server, and client. Tests are written by defining the elements and expected results. Varnishtest is useful for testing what happens in production Varnish and debugging issues. The presenter provides an example test script and explains how to run Varnishtest to check for passing or failing tests.

2. VARNISHTEST

3. A (not) well documented test tool

4. Arianna Aondio
Field Engineer
WHO AM I?

Email: arianna.aondio@varnish-software.com

Twitter: aondio_

Github: aondio

5. AGENDA

What (is varnishtest)?

Where (is it)?

When (should it be used)?

Who (should use it)?

Why (should I learn about it)?

How (to implement one)?

Questions

6. WHAT (IS VARNISHTEST) ?
Script driven program that lets you test your Varnish

7. WHERE (IS IT) ?
If you have Varnish installed, you already have it.
SURPRISE

9. WHEN (SHOULD IT BE USED) ?
You don't know
what's happening
with your Varnish in
production
Brilliant
solution
Test

10. WHO (SHOULD USE IT) ?
Developers
VMODS writers, ergo developers
Whoever wants to learn about Varnish

11. WHY (SHOULD I LEARN ABOUT IT) ?
Mostly because you don't want your Varnish to
explode...

12. ...but if it happens you want to debug it as soon as
possible!

14. HOW?
It’s easy
ServerVarnishClient

15. server s1 {
rxreq
txresp -hdr "x-continent: Europe"
} -start
DEFINE A SERVER

16. varnish v1 -vcl+backend {
sub vcl_recv {
if (req.http.x-city == "London") {
set req.http.x-country = "UK";
return (hash);
}
}
sub vcl_deliver {
set resp.http.x-country = req.http.x-country;
}
} -start
DEFINE A VARNISH INSTANCE

17. client c1 {
txreq -hdr "x-city == London”
rxresp
expect resp.http.x-country == "UK"
expect resp.http.x-continent == "Europe"
} -run
DEFINE A CLIENT

18. STICK THEM TOGETHER
server s1 {
rxreq
txresp -hdr "x-continent: Europe"
} -start
varnish v1 -vcl+backend {
sub vcl_recv {
if (req.http.x-city == "London") {
set req.http.x-country = "UK";
return (hash);
}
}
sub vcl_deliver {
set resp.http.x-country = req.http.x-country;
}
} -start
client c1 {
txreq -hdr "x-city: London"
rxresp
expect resp.http.x-country == "UK"
expect resp.http.x-continent == "Europe"
} -run

19. Run this command:
varnishtest my-beautiful-tc.vtc
It passes
It fails

20. Run varnishtest in verbose mode and get a
full log output:
varnishtest -v my-beautiful-tc.vtc
Useful to understand...

21. ...why your test case fails

22. Or why it works

23. QUESTIONS ?

24. THANK YOU