Let's you cache debian packages.
Here's my deployment.
Now when auto installing linux I can point it to this as a proxy
#cloud-config autoinstall: version: 1 proxy: http://git.local-domain:8000/
However this doesn't cache https traffic. Squid just forwards this straight to the origin server so it has no way to cache it.
For an https connection we see this in /var/log/squid/access.log
1596531928.807 94 10.0.0.2 TCP_TUNNEL/200 2013 CONNECT registry.local-domain:5003 - HIER_DIRECT/192.168.2.1 -
This repo shows how to run squid in various different modes.
docker run -p 3128:3128 -ti docker.io/salrashid123/squidproxy /bin/bash
This deploys a squid caching proxy with a self signed CA. If you trust the CA you can use the service.