#!/usr/bin/env sh
# Configurable Variables
DOCKER_SOCK_PATH="/tmp/docker.sock"
HOST_CONF_PATH="/tmp/hosts"
NETWORK_NAME="proxy"

query_docker () {
    echo $(curl --unix-socket $DOCKER_SOCK_PATH --silent -g http://v1.41/$1/json$2)
}

while true
do
    PROXY_HOST_CONF=""
    CONTAINER_LIST=$(query_docker "containers" "?filters={%22network%22:[%22${NETWORK_NAME}%22],%22status%22:[%22running%22]}" | jq -cr '.[].Id')

    for id in $CONTAINER_LIST
    do
        # Query individual container to access Env variables
        # Filter Env for HOSTNAME, remove list parenthesis and split/only keep values
        HOST_NAMES=$(query_docker "containers/${id}" | jq -cr '.Config.Env[] | select(contains("VIRTUAL_HOST=")) | split("=")[1]')

        for hostname in $HOST_NAMES
        do
            PROXY_HOST_CONF="$PROXY_HOST_CONF\n127.0.0.1 $hostname # Added by hostman"
        done
    done

    FILTERED_HOSTS=$(grep -ve "# Added by hostman$" $HOST_CONF_PATH)
    echo -e "$FILTERED_HOSTS$PROXY_HOST_CONF" > $HOST_CONF_PATH
    sleep 10
done