s4l3h1/nginx-fwd repository overview

⁠nginx-fwd

A minimal Docker image that runs nginx as a reverse proxy / TCP forwarder. Configuration is fully driven by environment variables at container startup — no config files to edit.

⁠How it works

On start, entrypoint.sh uses envsubst to render nginx.conf.template into a live nginx config, then launches nginx in the foreground. The resulting proxy:

• Listens on port 80
• Forwards all traffic to UPSTREAM_URL
• Sets the Host header to PROXY_HOST
• Supports WebSocket upgrades
• Exposes a /healthz endpoint that returns 200 ok
• Uses long timeouts (24 h) suitable for persistent connections

⁠Required environment variables

The container will refuse to start if either variable is missing.

⁠Usage

docker run -p 80:80 \
  -e UPSTREAM_URL=http://10.0.0.1:3000 \
  -e PROXY_HOST=myapp.internal \
  nginx-fwd

⁠Build

docker build -t nginx-fwd .

⁠Health check

curl http://localhost:80/healthz
# ok

⁠Docker Compose example

services:
  proxy:
    build: .
    ports:
      - "80:80"
    environment:
      UPSTREAM_URL: http://backend:3000
      PROXY_HOST: backend