Slim image (18MB) of Squid 3.5.4 running under Alpine Linux 3.2.
docker run -p 3128:3128 chrisdaish/squid
With bespoke configuration:
docker run -v <configPath>/squid.conf:/etc/squid/squid.conf:ro \
-v <configPath/cache:/var/cache/squid:rw \
-v /var/log/squid:/var/log/squid:rw \
-v /etc/localtime:/etc/localtime:ro \
-p 3128:3128 \
chrisdaish/squid