Update README and add Docker Compose example (#2)

* 📃 docs: readme by AI

* 📦 build: docker compose and env example

.env.example

@@ -0,0 +1,5 @@
+NODE_ENV=production
+
+# Referenced from configs/UpdaterConfig.json as "{ENV_TOKEN:EXAMPLE_SITE_TOKEN}".
+# Create a Cloudflare API token with DNS edit access for the target zone.
+EXAMPLE_SITE_TOKEN=replace-with-cloudflare-api-token

README.md

@@ -1 +1,224 @@
-# Cloudflare-DDNS-Updater
+# Cloudflare DDNS Updater
+
+Cloudflare DDNS Updater keeps Cloudflare DNS records pointed at the machine's current public IPv4 and/or IPv6 address.
+
+The container reads:
+
+- Environment variables from Docker, usually via `--env-file .env`.
+- DNS update rules from `/home/node/app/configs/UpdaterConfig.json` inside the container.
+
+## Quick Start
+
+Pull the published image:
+
+```sh
+docker pull ghcr.io/yuzuzensai/cloudflare-ddns-updater:latest
+```
+
+Create `.env` from the example:
+
+```sh
+cp .env.example .env
+```
+
+Edit `.env` and set your Cloudflare API token:
+
+```env
+NODE_ENV=production
+EXAMPLE_SITE_TOKEN=replace-with-cloudflare-api-token
+```
+
+Create `configs/UpdaterConfig.json`:
+
+```json
+[
+  {
+    "token": "{ENV_TOKEN:EXAMPLE_SITE_TOKEN}",
+    "updateInterval": 60,
+    "zone": [
+      {
+        "id": "cloudflare-zone-id",
+        "type": "A",
+        "name": "example.com",
+        "content": "{CURRENT_IPv4}",
+        "ttl": 1,
+        "proxied": false
+      },
+      {
+        "id": "cloudflare-zone-id",
+        "type": "AAAA",
+        "name": "example.com",
+        "content": "{CURRENT_IPv6}",
+        "ttl": 1,
+        "proxied": false
+      }
+    ]
+  }
+]
+```
+
+Run the container:
+
+```sh
+docker run -d \
+  --name cloudflare-ddns-updater \
+  --restart unless-stopped \
+  --env-file .env \
+  -v "$(pwd)/configs:/home/node/app/configs" \
+  ghcr.io/yuzuzensai/cloudflare-ddns-updater:latest
+```
+
+View logs:
+
+```sh
+docker logs -f cloudflare-ddns-updater
+```
+
+## Docker Compose
+
+```yaml
+services:
+  cloudflare-ddns-updater:
+    image: ghcr.io/yuzuzensai/cloudflare-ddns-updater:latest
+    container_name: cloudflare-ddns-updater
+    restart: unless-stopped
+    env_file:
+      - .env
+    volumes:
+      - ./configs:/home/node/app/configs
+```
+
+Start it with:
+
+```sh
+docker compose up -d
+```
+
+## Configuration
+
+`configs/UpdaterConfig.json` is an array of Cloudflare account/token configurations.
+
+Each top-level object uses these fields:
+
+- `token`: Cloudflare API token, or an environment reference like `{ENV_TOKEN:EXAMPLE_SITE_TOKEN}`.
+- `updateInterval`: update interval in seconds.
+- `zone`: DNS records to manage.
+
+Each `zone` entry uses these fields:
+
+- `id`: Cloudflare zone ID.
+- `type`: DNS record type, usually `A` or `AAAA`.
+- `name`: DNS record name, for example `example.com` or `home.example.com`.
+- `content`: `{CURRENT_IPv4}` for an `A` record or `{CURRENT_IPv6}` for an `AAAA` record.
+- `ttl`: Cloudflare TTL. Use `1` for automatic TTL.
+- `proxied`: Cloudflare proxy status, `true` or `false`.
+
+Important: keep the JSON property order shown in the examples. The current config validator expects exact key order.
+
+## Cloudflare Zone ID And Token
+
+You need two Cloudflare values before running the updater:
+
+- Zone ID: identifies the Cloudflare zone/domain that contains the DNS records.
+- API token: authorizes the updater to read and edit DNS records in that zone.
+
+The Zone ID goes in `configs/UpdaterConfig.json` as `zone[].id`.
+
+The API token should go in `.env`, then `configs/UpdaterConfig.json` references it with `{ENV_TOKEN:VARIABLE_NAME}`. The variable name is up to you. `EXAMPLE_SITE_TOKEN`, `HOME_SITE_TOKEN`, `MY_DOMAIN_TOKEN`, or any other valid environment variable name will work as long as both files use the same name.
+
+### Get Your Zone ID
+
+1. Log in to the [Cloudflare dashboard](https://dash.cloudflare.com/).
+2. Select the domain you want to update.
+3. Open the domain overview page.
+4. Find `Zone ID` in the right sidebar under `API`.
+5. Copy that value into each matching `zone[].id` field in `configs/UpdaterConfig.json`.
+
+Example:
+
+```json
+{
+  "id": "023e105f4ecef8ad9ca31a8372d0c353",
+  "type": "A",
+  "name": "home.example.com",
+  "content": "{CURRENT_IPv4}",
+  "ttl": 1,
+  "proxied": false
+}
+```
+
+### Create an API Token
+
+1. Log in to the [Cloudflare dashboard](https://dash.cloudflare.com/).
+2. Click your profile icon in the top-right corner.
+3. Open `My Profile`.
+4. Open `API Tokens`.
+5. Select `Create Token`.
+
+The easiest option is the built-in template:
+
+1. Find the `Edit zone DNS` template.
+2. Select `Use template`.
+3. Under `Zone Resources`, select `Include` > `Specific zone` > your domain.
+4. Leave the permissions as DNS edit/read permissions.
+5. Select `Continue to summary`.
+6. Review the token summary.
+7. Select `Create Token`.
+8. Copy the token immediately. Cloudflare only shows it once.
+
+If you create a custom token instead, use this setup:
+
+1. Select `Create Custom Token`.
+2. Give it a clear name, for example `Cloudflare DDNS Updater`.
+3. Add these permissions:
+
+- `Zone` > `DNS` > `Edit`
+- `Zone` > `Zone` > `Read`
+
+Set the zone resource scope:
+
+1. Under `Zone Resources`, choose `Include`.
+2. Choose `Specific zone`.
+3. Select the domain this updater will manage.
+4. Select `Continue to summary`.
+5. Review the token summary.
+6. Select `Create Token`.
+7. Copy the token immediately. Cloudflare only shows it once.
+
+Do not use your Global API Key. This app only needs a scoped API token with DNS access for the selected zone.
+
+After creating the token, copy it into `.env`. The name before `=` is the environment variable name. You can change it.
+
+```env
+EXAMPLE_SITE_TOKEN=your-cloudflare-api-token
+```
+
+If you change the variable name in `.env`, update the `token` value in `configs/UpdaterConfig.json` to match it exactly.
+
+Example:
+
+```env
+HOME_SITE_TOKEN=your-token
+```
+
+```json
+"token": "{ENV_TOKEN:HOME_SITE_TOKEN}"
+```
+
+Another example with a different name:
+
+```env
+MY_DOMAIN_TOKEN=your-token
+```
+
+```json
+"token": "{ENV_TOKEN:MY_DOMAIN_TOKEN}"
+```
+
+Do not include the literal token in `UpdaterConfig.json` unless you intentionally want the secret stored there. Using `{ENV_TOKEN:...}` keeps the token in `.env`, which is ignored by git.
+
+## Notes
+
+- The updater fetches IPv4 from `https://api.ipify.org?format=json`.
+- The updater fetches IPv6 from `https://api64.ipify.org/?format=json`.
+- If `configs/UpdaterConfig.json` is missing, the app creates one from the bundled example, but you must edit it before real use.

docker-compose.yml

@@ -0,0 +1,9 @@
+services:
+  cloudflare-ddns-updater:
+    image: ghcr.io/yuzuzensai/cloudflare-ddns-updater:latest
+    container_name: cloudflare-ddns-updater
+    restart: unless-stopped
+    env_file:
+      - .env
+    volumes:
+      - ./configs:/home/node/app/configs