Maps a dynamically allocated docker port to a chosen static port. Watches for updates.

staticDockerPortMapper.zsh

func staticDockerPortMapper(){
    [[ $# -lt 3 ]] && >&2 echo "usage: $0 <container-name/id> <exposed-container-port>/<tcp|udp> <static-port>" && return
    local container=$1
    local internalPort=$2
    local staticPort=$3

    local currentPid=$(lsof -ti :$staticPort 2>/dev/null)

    if [[ -n $currentPid ]]
    then
        command=$(ps -h --format %c $currentPid)
        read -k 1 -r "?Kill process $currentPid/$command already on your static port $staticPort? [y/n]" 
        echo
        if [[ $REPLY =~ ^[Yy]$ ]]
        then
            kill $currentPid >/dev/null 2>&1 
        else
            echo "Well not killing it is probably not going to work but ok..."
        fi
    fi

    local pid=
    local port=

    while true
    do

        local currentPort=$(docker inspect $container|jq ".[0].NetworkSettings.Ports.\"$internalPort\"| .[0].HostPort|tonumber")

        if [[ ! $? ]]
        then
            >&2 echo Port Not Found
        elif [[ "$currentPort" -ne "$port" ]]
        then
            echo "Mapping $currentPort to $staticPort"
            port="$currentPort"

            [[ -n $pid ]] && echo "Killing old socat command at $pid" && kill "$pid"
            socat tcp-listen:$staticPort,reuseaddr,fork tcp:localhost:$port &
        fi
        sleep 5
    done
}