How to work with Vmod Xkey to invalidate object in cache - varnish

Question

I'm using xKey Vmode plugin to purge objects through tags. I did set up my varnish configuration to work and support xkey but now I didn't find any resource on how to send that data through varnishadm or vcl. currently, I'm using HTTP ban
curl -X BAN -H 'X-Purge-Regex: 1.pbf' varnish
to invalidate with BAN.
Also is that possible to send xkey value with commoa seperated?
like: my cached URL is something like:
www.example.com/foo/xyz?name="t1;t2"
www.example.com/foo/abc?name="t1
www.example.com/foo/xyz?name="t2"
Currently, with BAN URL - i pass t1 value with regex and that is able to invalidate #1 and #2,
but now with Xkey
How to send http with xkey?
Is there a way Xkey supports multiple tags in a single request?
Can I send xkey with (xyz, t2) - With this, I want to invalidate #1 and #2.

Answer 1

Install vmod_xkey
In order to use vmod_xkey, you need to install it by compiling https://github.com/varnish/varnish-modules from source. Please make sure you select the right branch in GitHub, based on the Varnish version you use.
The xkey API
vmod_xkey has 2 functions:
xkey.purge(), which will immediately remove content from cache
xkey.softpurge(), which will mark content as expired, but keeps it around for asynchronous revalidation
The VCL code
Here's the VCL code you can use to invalidate content using tags:
vcl 4.1;
import xkey;
import std;
acl purge {
"localhost";
"192.168.55.0"/24;
}
sub vcl_recv {
if (req.method == "PURGE") {
if (!client.ip ~ purge) {
return(synth(405));
}
if(!req.http.x-xkey-purge) {
return(synth(400,"x-xkey-purge header missing"));
}
set req.http.x-purges = xkey.purge(req.http.x-xkey-purge);
if (std.integer(req.http.x-purges,0) != 0) {
return(synth(200, req.http.x-purges + " objects purged"));
} else {
return(synth(404, "Key not found"));
}
}
}
Please ensure acl purge contains the right IP addresses or IP ranges prior to using this.
By adding import xkey; to the VCL file, secondary keys are automatically registered in Varnish, and can be used later on.
The PURGE request method is used to trigger xkey.purge() and the x-xkey-purge request header is used to specify the tags.
Registering keys
Registering keys happens by specifying them in the Xkey response header. You can register a single key, but you can also add multiple ones.
Multiple keys are separated by space or comma.
Here's an example where 3 keys are registered:
category_sports
id_1265778
type_article
HTTP/1.1 200 OK
Content-Type: text/html; charset=UTF-8
Cache-Control: public, s-maxage=60
Xkey: category_sports id_1265778 type_article
Removing content based on keys
By performing a PURGE call and by specifying the right X-Xkey-Purge value, content will be removed for these keys.
Here's an example where we remove all objects matching the category_sports tag for all pages on the http://example.com website:
PURGE / HTTP/1.1
Host: example.com
X-Xkey-Purge: category_sports
Here's another example where we invalidate content that matches the foo and bar keys:
PURGE / HTTP/1.1
Host: example.com
X-Xkey-Purge: foo bar