Use APP_PORT consistently

.dockerignore

@@ -8,6 +8,6 @@ pnpm-debug.log*
 *.log
 .env
 .env.*
+!.env.example
 Dockerfile
 compose.yaml
-

.env.example

@@ -0,0 +1,2 @@
+APP_PORT=8787
+

Dockerfile

@@ -3,15 +3,14 @@ FROM node:24-alpine
 WORKDIR /app
 
 ENV NODE_ENV=production
-ENV PORT=3000
+ENV APP_PORT=8787
 
 COPY package.json ./
 COPY index.html styles.css game.js server.js ./
 
-EXPOSE 3000
+EXPOSE 8787
 
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
-  CMD node -e "fetch('http://127.0.0.1:' + (process.env.PORT || 3000) + '/healthz').then(r => process.exit(r.ok ? 0 : 1)).catch(() => process.exit(1))"
+  CMD node -e "fetch('http://127.0.0.1:' + (process.env.APP_PORT || 8787) + '/healthz').then(r => process.exit(r.ok ? 0 : 1)).catch(() => process.exit(1))"
 
 CMD ["node", "server.js"]
-

README.md

@@ -13,6 +13,8 @@ A notepad-playable browser game that combines Tic Tac Toe's line-making goal wit
 
 ## Run With Docker Compose
 
+Optional: copy `.env.example` to `.env` and change `APP_PORT`.
+
 ```powershell
 docker compose up --build
 ```
@@ -37,12 +39,12 @@ docker compose down
 npm start
 ```
 
-Then open `http://localhost:3000` in two browser windows.
+Then open `http://localhost:8787` in two browser windows.
 
 Set a different port with:
 
 ```powershell
-$env:PORT=4000; npm start
+$env:APP_PORT=9090; npm start
 ```
 
 ## Notes

compose.yaml

@@ -6,6 +6,6 @@ services:
     container_name: tictactics
     restart: unless-stopped
     environment:
-      PORT: 3000
+      APP_PORT: ${APP_PORT:-8787}
     ports:
-      - "${APP_PORT:-8787}:3000"
+      - "${APP_PORT:-8787}:${APP_PORT:-8787}"

server.js

@@ -3,7 +3,7 @@ const fs = require("fs");
 const http = require("http");
 const path = require("path");
 
-const port = Number(process.env.PORT || 3000);
+const appPort = Number(process.env.APP_PORT || 8787);
 const root = __dirname;
 const clients = new Map();
 const rooms = new Map();
@@ -286,6 +286,6 @@ function encodeFrame(message) {
   return Buffer.concat([header, payload]);
 }
 
-server.listen(port, () => {
-  console.log(`Tictactics multiplayer server running at http://localhost:${port}`);
+server.listen(appPort, () => {
+  console.log(`Tictactics multiplayer server running at http://localhost:${appPort}`);
 });