#!/bin/bash

##################################################
# Mount dir                                      #
# - /opt/kafka/data                              #
# - /opt/kafka/logs                              #
# ENV                                            #
# - KAFKA_OPTS                                   #
# - _CONF_*                                      #
##################################################

set -euo pipefail
export LANG=en_US.UTF-8
trap Quit EXIT

PIDS=
GOT_SIGTERM=

function Print {
    local file=/dev/null
    [ '-f' = "$1" ] && file=$2 && shift && shift
    date +"[%F %T] $*" | tee -a $file
}

function Quit {
    while :; do
        pkill -f java && Print killing java ... || break
        sleep 1
    done
    Print Container stopped.
    test -n "$GOT_SIGTERM"
}

function Usage {
    Print 'This container should run with
    **root user**
    **/opt/kafka/{data,logs} mounted from host**
    '
}

function ModifyConf {
    Print Modifying server.properties ...
    local kv=
    local conf='config/server.properties'
    while read kv; do
        [ -z "$kv" ] && break
        Print Modifying property: ${kv%%=*} ...
        sed -i "/^${kv%%=*} *=/d" $conf
        echo "$kv" >> $conf
    done <<< "$(env | grep '^_CONF_' | sed 's/_CONF_//')"
}

function StartProc {
    Print Starting kafka ...
    ./bin/kafka-server-start.sh ./config/server.properties --override log.dirs=./data \
        &>> logs/kafka.out &
    PIDS="$PIDS $!"
    Print Kafka started.
}

function Main {
    local pid=
    cd /opt/kafka
    Usage
    ModifyConf
    StartProc
    trap "GOT_SIGTERM=1; Print Got SIGTERM ..." SIGTERM
    while [ -z "$GOT_SIGTERM" ] && sleep 2; do
        for pid in $PIDS; do
            [ ! -e /proc/$pid ] && Print Unexpected error! && exit
        done
    done
}

# Start here
Main