Updated Ip-Check - Custom Dynamic DNS for AWS Route 53

ip-check.sh

#!/bin/bash

#Variable Declaration - Change These
HOSTED_ZONE_ID="Z0244******"
#test/dummy subdomain to see if my IP has changed
NAME="dynamic-dns.*********.net."
#My websites that need there IP address updated
CRITTER="development.*********.net."
IDENTITY="development.*********.net."
GATEWAY="development.*********.net."
TYPE="A"
#Using 60 for the health check to prevent long DNS caching time
HEALTH_CHECK_TTL=60
#Using 300 for my websites - at most my websites won't work for 5 minutes (browser may cache DNS entries) but AWS ROUTE 53 updates #DNS pretty fast
TTL=300

#Get current IP address
IP=$(curl http://checkip.amazonaws.com/)

#validate IP address (makes sure Route 53 doesn't get updated with a malformed payload)
if [[ ! $IP =~ ^[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}$ ]]; then
	exit 1
fi


#get current ip - uses AWS query option for server side filtering instead of client-side using jq
# --query uses JMESPath syntax. similar to jq 
# https://jmespath.org/tutorial.html
aws route53 list-resource-record-sets --hosted-zone-id $HOSTED_ZONE_ID --profile home-server  \
--query "ResourceRecordSets[?Name == 'dynamic-dns.fullstackindie.net.'].ResourceRecords[0].Value" --output text > /home/murph/workspace/cron-jobs/current_route53_value

# add file to keep track of last update time
LAST_UPDATE_TIME=$(date --iso-8601=seconds)
cat > /home/murph/workspace/cron-jobs/cron_updates << EOF
$LAST_UPDATE_TIME
EOF


#check if IP is different from Route 53
if grep -Fxq "$IP" /home/murph/workspace/cron-jobs/current_route53_value; then
	echo "IP Has Not Changed, Exiting"
	exit 1
fi


echo "IP Changed, Updating Records"

#prepare route 53 payload
cat > /home/murph/workspace/cron-jobs/route53_changes.json << EOF
    {
      "Comment":"Updated From DDNS Shell Script",
      "Changes":[
        {
          "Action":"UPSERT",
          "ResourceRecordSet":{
            "ResourceRecords":[
              {
                "Value":"$IP"
              }
            ],
            "Name":"$NAME",
            "Type":"$TYPE",
            "TTL":$HEALTH_CHECK_TTL
          }
        },
        {
          "Action":"UPSERT",
          "ResourceRecordSet":{
            "ResourceRecords":[
              {
                "Value":"$IP"
              }
            ],
            "Name":"$CRITTER",
            "Type":"$TYPE",
            "TTL":$TTL
          }
        },
        {
          "Action":"UPSERT",
          "ResourceRecordSet":{
            "ResourceRecords":[
              {
                "Value":"$IP"
              }
            ],
            "Name":"$IDENTITY",
            "Type":"$TYPE",
            "TTL":$TTL
          }
        },
        {
          "Action":"UPSERT",
          "ResourceRecordSet":{
            "ResourceRecords":[
              {
                "Value":"$IP"
              }
            ],
            "Name":"$GATEWAY",
            "Type":"$TYPE",
            "TTL":$TTL
          }
        }
      ]
    }
EOF

#update records
sudo aws route53 change-resource-record-sets --hosted-zone-id $HOSTED_ZONE_ID --change-batch file:///home/murph/workspace/cron-jobs/route53_changes.json >> /var/log/ip-check.log