An image based off the official certbot docker image which includes a cron job to automatically renew certificates. Still requires a bit of manual work to initially set up. See official documentation for information on how to set it up for the first time.
Pulling down the image: docker pull aghost7/certbot
This image is designed so that you run the reverse proxy in a separate container. To make it work with haproxy, you would include in your configuration something along the following lines:
frontend front-https
bind *:443 crt /etc/haproxy/certs/example.com.pem
acl acme_challenge path_beg /.well-known/acme-challenge/
use backend certbot if acme_challenge
# You would have more acls, and a default backend in here.
backend certbot
server certbot-server your_certbot_ip:6000
Digitalocean has a very good tutorial on how to get this working.