Web server that returns IP and request count

This minimal web server can be used for testing load balancers and reverse proxies.

It returns a text response with the IP of the webserver and the number of requests it has received, like

Server: worker-1
Container IPs: 10.0.0.113,172.18.0.5,10.0.1.126
Visits: 6

Host: counter.mycompany.com
X-Forwarded-For: 34.230.12.56

Run it by

docker run -d -p 8080:8080 --name ip-and-counter jpsecher/ip-and-counter $(hostname)

Stop it by

docker kill ip-and-counter

It has a non-counting health endpoint at /health. It can be used in a Docker Swarm setting like

version: '3.8'
services:
  counter:
    image: jpsecher/ip-and-counter
    environment:
      hostname: "{% raw %}{{.Node.Hostname}}{% endraw %}"
    ports:
      - target: 8080
    healthcheck:
      test: ["CMD", "node", "-e", "fetch('http://localhost:8080/health').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))"]
    networks:
      - loadbalancer
    deploy:
      mode: global
      labels:
        - "traefik.http.services.counter.loadbalancer.server.port=8080"
        - "traefik.http.routers.counter.entrypoints=public"
        - "traefik.http.routers.counter.rule=Host(`counter.{{ domain }}`)"
networks:
  loadbalancer:
    external: true

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