#!/bin/bash
set -euo pipefail
[[ -n "${DEBUG:-}" ]] && set -x
[[ 0 -eq "$#" ]] && set -- start

ufw_docker_agent=ufw-docker-agent
ufw_docker_agent_image="${ufw_docker_agent_image:-chaifeng/${ufw_docker_agent}:181003}"

function ufw-allow-or-deny-service() {
    declare id="$1"
    declare port="$2"

    if [[ "$port" = deny ]]; then
        run-ufw-docker delete allow "$id"
    else
        run-ufw-docker add-service-rule "$id" "$port"
    fi
}

function update-ufw-rules() {
    declare -p | sed -e '/^declare -x ufw_public_/!d' \
                     -e 's/^declare -x ufw_public_//' \
                     -e 's/="/ /' \
                     -e 's/"$//' |
        while read id port; do
            ufw-allow-or-deny-service "${id}" "${port%*/}"
        done
}

function run-ufw-docker() {
    declare -a docker_opts=(run --rm -t --name ufw-docker-agent-"${RANDOM}"-$(date '+%Y%m%d%H%M%S')
         --cap-add NET_ADMIN --network host
         --env DEBUG="$DEBUG"
         --env UFW_DOCKER_FORCE_ADD=yes
         -v /var/run/docker.sock:/var/run/docker.sock
         -v /etc/ufw:/etc/ufw "${ufw_docker_agent_image}" "$@")
    docker "${docker_opts[@]}"
}

function get-service-name-of() {
    docker inspect "$1" --format '{{range $k,$v:=.Config.Labels}}{{ if eq $k "com.docker.swarm.service.name" }}{{$v}}{{end}}{{end}}' | grep -E "^.+\$"
}

function get-service-id-of() {
    docker inspect "$1" --format '{{range $k,$v:=.Config.Labels}}{{ if eq $k "com.docker.swarm.service.id" }}{{$v}}{{end}}{{end}}' | grep -E "^.+\$"
}

function main() {
    case "$1" in
        start)
            update-ufw-rules
            docker events --format '{{.Time}} {{.Status}} {{.Actor.Attributes.name}}' --filter 'scope=local' --filter 'type=container' |
                while read time status name; do
                    echo "$time $status $name" >&2
                    [[ -z "$name" ]] && continue

                    [[ "$status" = @(kill|start) ]] || continue

                    declare -n env_name="ufw_public_$(get-service-id-of "$name")"
                    [[ -z "${env_name:-}" ]] && continue

                    declare port="${env_name:-deny}"
                    if [[ "$status" = kill ]]; then
                        port=deny
                    fi

                    echo ufw-update-rule-for-instance "$name" "$port"
                done
            sleep 60; exit 1
            ;;
        delete|allow|add-service-rule)
            ufw-docker "$@"
            ;;
        update-ufw-rules)
            update-ufw-rules
            ;;
        *)
            if [[ -f "$1" ]]; then
                exec "$@"
            else
                echo "Unknown parameters: $@" >&2
                exit 1
            fi
    esac
}

main "$@"