Docker haproxy with http logging through syslog proxying to local port (for debugging)

docker-compose-haproxy-with-logging.yml

version: "2"
services:
    rsyslog:
        image: jumanjiman/rsyslog
    proxy:
        image: haproxy
        volumes:
            - ./:/cfg
        volumes_from:
            - rsyslog
        command: haproxy -f /cfg/haproxy.cfg
        network_mode: "host"
        ports:
            - "80:80"

haproxy.cfg

global
    daemon
    maxconn 256
    log /var/run/rsyslog/dev/log local0
    log /var/run/rsyslog/dev/log local1


defaults
    mode http
    timeout connect 5000ms
    timeout client 50000ms
    timeout server 50000ms

frontend http-in
    bind *:80
    default_backend servers
    capture cookie COOKIENAME len 32
    log global
    option httplog

backend servers
    server server1 127.0.0.1:8080 maxconn 32

Fire up using docker-compose (using -f docker-compose-haproxy-with-logging.yml unless you change the name of the first file). This expects your application (that you want to proxy to, like I did, for debugging) to be residing on port 8080 on your local machine. If it is already in a container that is fine too - just remove the line containing network_mode: host since it is not needed (and should be avoided) and change the hostname for the backend in haproxy.cfg accordingly. The proxy will start up and occupy port 80 locally and logs can be seen by simply using docker log (or docker-compose log) on the rsyslog service.

...and the reason for learning this was that I was debugging cookies and http requests. This middleman at least could tell me who was lying. That is the reason the capture cookie ... line is there. Can be removed or changed to cookie whose name matches yours (the "COOKIENAME" part).