Symfony 5 and varnish - varnish

Question

I installed varnish on my server, it's active (checked via the sudo systemctl varnish restart command). I configured the /etc/varnish/default.vcl file following the tutorial https://symfony.com/doc/current/http_cache/varnish.html but I don't have the impression that varnish is taken into account on Symfony (I don't see X-Varnish in the response header (however it appears well when I access directly to my server via http://localhost/.
Here is my default.vcl file:
#
# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and https://www.varnish-cache.org/trac/wiki/VCLExamples for more examples.
# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;
# Default backend definition. Set this to point to your content server.
backend default {
.host = "127.0.0.1";
.port = "8080";
}
sub vcl_recv {
# Happens before we check if we have this in cache already.
#
# Typically you clean up the request here, removing cookies you don't need,
# rewriting the request, etc.
if (req.http.X-Forwarded-Proto == "https" ) {
set req.http.X-Forwarded-Port = "443";
} else {
set req.http.X-Forwarded-Port = "80";
}
# Remove all cookies except the session ID.
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 == "") {
// If there are no more cookies, remove the header to get page cached.
unset req.http.Cookie;
}
}
# Add a Surrogate-Capability header to announce ESI support.
set req.http.Surrogate-Capability = "abc=ESI/1.0";
}
sub vcl_backend_response {
# Happens after we have read the response headers from the backend.
#
# Here you clean the response headers, removing silly Set-Cookie headers
# and other mistakes your backend does.
# Check for ESI acknowledgement and remove Surrogate-Control header
if (beresp.http.Surrogate-Control ~ "ESI/1.0") {
unset beresp.http.Surrogate-Control;
set beresp.do_esi = true;
}
}
sub vcl_deliver {
# Happens when we have all the pieces we need, and are about to send the
# response to the client.
#
# You can do accounting or modifying the final object here.
}
Maybe then there is something to configure on symfony but I don't see what. Thank you.

Answer 1

If you're unsure that Varnish is correctly handling requests, you should check if the varnishd process runs on the right TCP port.
You can do this by running the following command:
sudo systemctl status varnish
In my case, this is the output:
● varnish.service - Varnish Cache Plus, a high-performance HTTP accelerator
Loaded: loaded (/lib/systemd/system/varnish.service; enabled; vendor preset: enabled)
Drop-In: /etc/systemd/system/varnish.service.d
└─override.conf
Active: active (running) since Fri 2021-04-09 17:50:00 UTC; 3min 5s ago
Main PID: 1242 (varnishd)
Tasks: 226
CGroup: /system.slice/varnish.service
├─1242 /usr/sbin/varnishd -a :80 -a 127.0.0.1:8443,proxy -S /etc/varnish/secret -T localhost:6082 -f /etc/varnish/default.vcl -s mse,/etc/varnish/mse.conf
└─1256 /usr/sbin/varnishd -a :80 -a 127.0.0.1:8443,proxy -S /etc/varnish/secret -T localhost:6082 -f /etc/varnish/default.vcl -s mse,/etc/varnish/mse.conf
The relevant information is the command that is executed, along with the runtime options and paramters.
In this case varnishd is listening for incoming connections on 2 ports:
80 for regular HTTP traffic
8443 for PROXY traffic
In your case, the listening ports may be configured differently.
Out the box, these are the default values:
/usr/sbin/varnishd \
-a :6081 \
-a localhost:8443,PROXY \
-p feature=+http2 \
-f /etc/varnish/default.vcl \
-s malloc,256m
As you can see port 6081 is used for incoming HTTP traffic. You may need to change this to port 80.
Just run the following command to edit the unit file:
sudo systemctl edit --full varnish
Once you've adjusted the runtime parameters, just run the following command to restart the service:
sudo systemctl restart varnish
WARNING: if you run Varnish on the same server as the webserver, you will need to change the listening port of the webserver as well. A good option is port 8080.