feat: respect PORT env variable for Coolify preview deployments

Nginx now listens on ${PORT} (default 7575) instead of hardcoded 7575,
so Coolify can inject a unique port per preview container. The internal
Next.js server is pinned to port 3000 to avoid conflicting with nginx.

Dockerfile

@@ -65,5 +65,8 @@ ENV AUTH_PROVIDERS='credentials'
 ENV REDIS_IS_EXTERNAL='false'
 ENV NODE_ENV='production'
 
+ARG PORT=7575
+EXPOSE ${PORT}
+
 ENTRYPOINT [ "/app/entrypoint.sh" ]
 CMD ["sh", "run.sh"]

apps/nextjs/package.json

@@ -9,7 +9,7 @@
     "dev": "pnpm with-env next dev",
     "format": "oxfmt .",
     "lint": "oxlint",
-    "start": "pnpm with-env next start",
+    "start": "pnpm with-env next start -p ${PORT:-3000}",
     "typecheck": "tsc --noEmit",
     "with-env": "dotenv -e ../../.env --"
   },

development/docker-run.cmd

@@ -1,2 +1,2 @@
 :: Please do not run this command in production. It is only for local testing.
-docker run -p 7575:7575 -e SECRET_ENCRYPTION_KEY=0000000000000000000000000000000000000000000000000000000000000000 homarr:latest
+docker run -p 7575:7575 -e PORT=7575 -e SECRET_ENCRYPTION_KEY=0000000000000000000000000000000000000000000000000000000000000000 homarr:latest

nginx.conf

@@ -4,8 +4,8 @@ events {
 
 http {
     server {
-        listen 7575;
-        listen [::]:7575;
+        listen ${PORT};
+        listen [::]:${PORT};
 
         # Route websockets traffic to port 3001
         location /websockets {

scripts/run.sh

@@ -17,12 +17,14 @@ fi
 # Auth secret is generated every time the container starts as it is required, but not used because we don't need JWTs or Mail hashing
 export AUTH_SECRET=$(openssl rand -base64 32)
 
+export PORT=${PORT:-7575}
+
 # Start nginx proxy
-# 1. Replace the HOSTNAME in the nginx template file
+# 1. Replace the HOSTNAME and PORT in the nginx template file
 # 2. Create the nginx configuration file from the template
 # 3. Start the nginx server
 export HOSTNAME
-envsubst '${HOSTNAME}' < /etc/nginx/templates/nginx.conf > /etc/nginx/nginx.conf
+envsubst '${HOSTNAME} ${PORT}' < /etc/nginx/templates/nginx.conf > /etc/nginx/nginx.conf
 # Start services in the background and store their PIDs
 nginx -g 'daemon off;' &
 NGINX_PID=$!
@@ -36,7 +38,7 @@ else
     REDIS_PID=$!
 fi
 
-node apps/nextjs/server.js &
+PORT=3000 node apps/nextjs/server.js &
 NEXTJS_PID=$!
 
 # Function to handle SIGTERM and shut down services