update route53 record from instance meta datas

gistfile1.sh

#!/bin/bash

MYDOMAIN="mydomain.com"
RECORD="myrecord.${MYDOMAIN}."

MYIP=$(curl -o- -s http://169.254.169.254/latest/meta-data/public-ipv4)
HOSTED_ZONE_ID=$(aws route53 list-hosted-zones-by-name --dns-name $MYDOMAIN | jq -r '.HostedZones[0].Id' | sed "s/\/hostedzone\///")

echo "Hosted zone being modified: $HOSTED_ZONE_ID"

INPUT_JSON=$(cat <<EOT
{
  "Comment": "Update the A record set",
  "Changes": [
    {
      "Action": "UPSERT",
      "ResourceRecordSet": {
        "Name": "${RECORD}",
        "Type": "A",
        "TTL": 300,
        "ResourceRecords": [
          {
            "Value": "${MYIP}"
          }
        ]
      }
    }
  ]
}
EOT
)
INPUT_JSON="{ \"ChangeBatch\": $INPUT_JSON }"

aws route53 change-resource-record-sets --hosted-zone-id "$HOSTED_ZONE_ID" --cli-input-json "$INPUT_JSON"