A bash script for running HAProxy as a Docker container with hot reloading support

start_haproxy.sh

#!/usr/bin/env bash

# A bash script for running HAProxy as a Docker container with hot reloading support
# 
# For example:
# $ docker run --name lb -p 80:8080 -p 443:8443 \
#     --log-driver=json-file --log-opt max-size=100M \
#     --log-opt max-file=1 \
#     -v $(pwd):/usr/local/etc/haproxy -tid \
#     haproxy:1.6 /usr/local/etc/haproxy/start_haproxy.sh

echo "$(date) : Starting HA Proxy..."

HAPROXY=/usr/local/etc/haproxy
# Restart haproxy every ${SLEEP_SEC} seconds (5 minutes by default)
SLEEP_SEC=${SLEEP_SEC:-300}

# Run HAProxy as a daemon
rm -f ${HAPROXY}/haproxy.pid
haproxy -D -f ${HAPROXY}/haproxy.cfg -p ${HAPROXY}/haproxy.pid
RET=$?
if [ "${RET}" == "0" ]; then
  cp -f ${HAPROXY}/haproxy.cfg ${HAPROXY}/haproxy.cfg.bak
else
  rm -f ${HAPROXY}/haproxy.cfg.bak
fi

echo "$(date) : Starting Configuration File Hot Reloading..."

while [ 1 ]; do
  diff -q ${HAPROXY}/haproxy.cfg ${HAPROXY}/haproxy.cfg.bak >/dev/null 2>&1
  RET=$?
  if [ "${RET}" != "0" ]; then
    haproxy -D -f ${HAPROXY}/haproxy.cfg -p ${HAPROXY}/haproxy.pid -sf $(cat ${HAPROXY}/haproxy.pid)
    RET=$?
    if [ "${RET}" == "0" ]; then
      echo "$(date) : Hot Reloading Successful"
      cp -f ${HAPROXY}/haproxy.cfg ${HAPROXY}/haproxy.cfg.bak
    else
      echo "$(date) : Hot Reloading Failed. Correct the cfg file and save it."
    fi
  fi
  sleep ${SLEEP_SEC}
done