add update-dns.sh script

update-dns.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+
+set -eux
+
+ip=$(wget https://checkip.amazonaws.com/ -O - -q)
+
+zone_id=$(aws route53 list-hosted-zones | jq -S '.HostedZones | .[] | select( .Name == "maxregan.me." ) | .Id' -r)
+
+batch=$(cat <<EOM
+{
+  "Changes": [
+    {
+      "Action": "UPSERT",
+      "ResourceRecordSet": {
+        "Name": "home.maxregan.me",
+        "Type": "A",
+        "TTL": $((30 * 60)),
+        "ResourceRecords": [
+          {
+            "Value": "${ip}"
+          }
+        ]
+      }
+    }
+  ]
+}
+EOM
+)
+
+aws route53 change-resource-record-sets --hosted-zone-id "${zone_id}" --change-batch "$batch"