It is my first HA add-on. Thank Kjell Hanken and SJ Chou, Referencing their sample allowed me to complete this add-on.
run.sh: Refer to SJ Chou's cf-ip-renew.sh and Kjell Hanken's run.sh.
Other details: Refer to Kjell Hanken's project to make a HA add-on.

This add-on is used to automatically update Cloudflare's dns records with your latest public ip address.

Installation

Go to the add-on store of the supervisor and click on repositories under the three dots. Copy https://github.com/Maboroshi0327/cloudflare-ddns-updater into the field and add this repository. Now you can install this add-on like any other home-assistant add-on.

Configuration

1. Create an API token at Cloudflare and give it Zone.DNS permissions.
2. Please refer to this tutorial to obtain the Zone ID and Record ID.
3. Enter these details into the add-on's settings page and start it.
   Your configuration should look similar to this:

DNS: <YOUR_Domain_Name>
CF_TOKEN: <YOUR_API_TOKEN>
CF_ZONE_ID: <YOUR_ZONE_ID>
CF_RECORD_ID: <YOUR_RECORD_ID>
proxied: false
time: 300