linux monitoring using slack

SLACK_WEBHOOK="https://hooks.slack.com/services/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"
SLACK_CHANNEL=${SLACK_CHANNEL-"testing"}
SLACK_USERNAME=${SLACK_USERNAME-"sai"}

[ -z $SLACK_WEBHOOK ] && { echo "The SLACK_WEBHOOK is not set!"; exit 1; }

# server status data

HOSTNAME=`hostname`
HOSTIP=`hostname -I | sed -r 's/(\S+) (\S+)/\1, \2/g'`
ROUTES=`ip route list scope global`
UPTIME=`uptime`
DISK=`df -hT /`
MEMORY=`free -h`

# sending the message

statusMessage() {
echo -e ":black_small_square: *${HOSTNAME}* - ${HOSTIP}\n"
echo -e "_Uptime:_\n\`\`\`${UPTIME}\`\`\`"
echo -e "_Memory:_\n\`\`\`${MEMORY}\`\`\`"
echo -e "_Disk:_\n\`\`\`${DISK}\`\`\`"
echo -e "_Routes:_\n\`\`\`${ROUTES}\`\`\`"
}

PAYLOAD="{\"channel\": \"#${SLACK_CHANNEL}\", \"username\": \"${SLACK_USERNAME}\", \"text\": \"`statusMessage`\"}"
curl -X POST --data-urlencode "payload=$PAYLOAD" $SLACK_WEBHOOK