[a] add metrics port export to Dockerfile

Dockerfile

@@ -1,10 +1,16 @@
+# container img
 FROM node:14
 WORKDIR /app
 
+# copy files and install deps
 COPY package*.json ./
 RUN npm install
 COPY . .
 
-#
+# main port
 EXPOSE 3000
+
+# metrics port
+EXPOSE 3001
+
 CMD ["node", "main.js"]

README.md

@@ -14,12 +14,14 @@ RATE_LIMIT_MINUTES=15 # the amount of time in minutes to rate limit
 RATE_LIMIT_REQUESTS=100 # amount of max. requests
 ```
 
-Don't change the `PORT` value when running in a Docker Container. Instead, export a different port and forward that to the container's port `3000`.
+Don't change the `PORT` and `METRICS_PORT` values when running in a Docker Container.
+Instead, export a different port and forward that to the container's ports `3000` and `3001` for the main API port and the metrics port respectively.
 
 ```yml
 # example for docker-compose.yml:
 ports:
   - "5678:3000"
+  - "6789:3001"
 ```
 
 You also have to mount the `.env` file inside the container, if you're using Docker:

compose.yml

@@ -3,6 +3,7 @@ services:
     image: gitpot.org/sangelo/plausible-pageviews-api:main
     container_name: plausible-pageviews-api
     ports:
-      - "3000:3000"
+      - "3000:3000" # main port
+      - "3001:3001" # metrics port
     volumes:
       - ./.env:/app/.env