reload-when-hosts-changed

#!/bin/sh

NAMES="$*"

if [ -z "$NAMES" ]; then
   echo "NAMES undefined, exiting"
   exit 1
fi

while true; do
    dig $NAMES |grep -v -e '^;' -v -e '^$' -v -e '^\.' > /tmp/addrs.new
    if test -e /tmp/addrs; then
         if ! cmp -s /tmp/addrs.new /tmp/addrs; then
            /usr/local/openresty/bin/openresty -s reload
            echo '-- reload'
        fi
    fi
    mv /tmp/addrs.new /tmp/addrs
    sleep 10
done