telegram reminder - liamlamth/blog GitHub Wiki

feature

  1. sending email to a server mailbox.
  2. server grep a pattern in new mail and convert to a pending alarm.
  3. server calls the telegram api to send out message.

notes

  1. mutt is good for parsing raw mail, e.g. base64. procmail and mailx have their drawback to do so.
  2. relaying reply in the mail cannot be isolate.
  3. mutt interactive scripting cannot be normally used in cronjob, it required stdin. To bypass this, use screen
  • mutt setting 
    $ mkdir /root/Mail
$ touch /root/Mail/decode_mail
$ vi /root/.muttrc
    save-hook . '=decode_mail'
  • cron 
    * * * * * /root/telegram_remind.sh
  • script 
    $ touch /root/telegram_remind_schedule.txt
$ vi /root/telegram_remind.sh
    #!/usr/bin/sh
    
    NOW=$(date "+%Y-%m-%d %H:%M")
    declare -A RECIPIENT
    RECIPIENT["REMINDER"]="-8123123"
    BOT_TOKEN="2100123123:AAF0WZqCc4Fe5r1aWsVwKuJPDAA231G231M"
    SCHEDULE_FILE=/root/telegram_remind_schedule.txt
    RAW_MAIL=/var/mail/root
    DECODE_MAIL=/root/Mail/decode_mail
    IFS=$'\n'
    
    touch $SCHEDULE_FILE
    REMIND_SCHEDULE=$(cat $SCHEDULE_FILE | grep "^pending,${NOW}" )
    
    if [ ! -z "$REMIND_SCHEDULE" ]; then
            for REMINDER in $(echo "$REMIND_SCHEDULE")
            do
                    REMIND_MSG=$( echo $REMINDER | cut -d ',' -f3- )
                    curl -X POST \
                            -H "Content-Type: application/json" \
                            -d "{\"chat_id\": \"${RECIPIENT[REMINDER]}\", \"text\": \"${REMIND_MSG}\"" \
                            https://api.telegram.org/bot${BOT_TOKEN}/sendMessage
                    sed -i "/${REMINDER}/s/^pending/completed/g" $SCHEDULE_FILE
                    echo ""
            done
    fi
    
    if [ ! -s $RAW_MAIL ]; then
            exit
    else
            while [[ -s $RAW_MAIL ]] && [[ $READ_COUNT < 10 ]]
            do
                    screen -d -m mutt -f $RAW_MAIL -e "push "
                    READ_COUNT=$(expr $READ + 1)
            done
    fi
    
    ### clean leading/tailing space: awk '{$1=$1};1'
    
    FILTER_MEMOS=$(cat $DECODE_MAIL | awk '{$1=$1};1' | grep -i "^From: [email protected]\|^hey zabbix" | sed '$aFrom: End')
    
    for MEMO in $(echo "$FILTER_MEMOS")
    do
            if [ $(echo $MEMO | grep -ic "^From: ") -eq 1 ]; then
                    if [ ! -z $SUCCESS_MEMO ] || [ ! -z $FAILED_MEMO ]; then
                            echo -e "${FAILED_MEMO}${SCHEDULE_COUNT} memo(s) is added into pending alarm list:-\n${SUCCESS_MEMO}" | mutt -s "telegram alarm schedule" -- $SENDER
                    fi
                    SENDER=$(echo $MEMO | grep -ioP '(?<=^From: ).*')
                    SCHEDULE_COUNT=0
                    unset SUCCESS_MEMO
                    continue
            fi
    
            if [ $(echo $MEMO | grep -o "," | wc -l) -lt 2 ]; then
                    FAILED_MEMO+="Not Enough Values, Please use  : ${MEMO}\n"
                    continue
            fi
            MEMO_TIME=$(echo $MEMO | cut -d ',' -f2  | awk '{$1=$1};1')
            MEMO_MSG=$( echo $MEMO | cut -d ',' -f3- | awk '{$1=$1};1')
    
            date -d "$MEMO_TIME" >/dev/null 2>&1
            if [ $? -eq 1 ]; then
                    FAILED_MEMO+="Bad Time Format, please use YYYY-MM-DD HH24:MI : ${MEMO}\n"
                    continue
            fi
    
            if [ $(date -d "$MEMO_TIME" +%s) -le $(date +%s) ]; then
                    FAILED_MEMO+="Time Over, please provide a future time : ${MEMO}\n"
                    continue
            fi
    
            FORMAT_TIME=$(date -d ${MEMO_TIME} +"%Y-%m-%d %H:%M")
            SCHEDULE_MEMO="${FORMAT_TIME},${MEMO_MSG}"
            if [ $(grep -c "${SCHEDULE_MEMO}$" $SCHEDULE_FILE) -gt 0 ]; then
                    FAILED_MEMO+="This Schedule is already Added : ${MEMO}\n"
                    continue;
            fi
            echo "pending,${SCHEDULE_MEMO}" >> $SCHEDULE_FILE
            SCHEDULE_COUNT=$(expr $SCHEDULE_COUNT + 1)
            SUCCESS_MEMO+="${SCHEDULE_MEMO}\n"
    done
    
    cat /dev/null > $DECODE_MAIL
    IFS=" "
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