Watch a log file and send a Slack message when there is new log.

motion_slack.sh

#!/bin/bash
set -e
LOG_FILE='/var/log/motion/motion.log'
WEBHOOK_URL='https://hooks.slack.com/services/...'
USERNAME='motion'
CHANNEL='camera'

function send_slack_message {
  DATA="payload={\"username\": \"${USERNAME}\", \"channel\": \"${CHANNEL}\", \"text\": \"$1\"}"
  echo "data: ${DATA}"
  curl -X POST --data-urlencode "${DATA}" "${WEBHOOK_URL}";
  echo ""
}

send_slack_message 'motion alert started!'

tail -n0 -F "${LOG_FILE}" | while read LINE; do
  send_slack_message "${LINE}"
done