Nginx proxy to two microservices

docker-compose.yml

# We demonstrate an nginx reverse proxy that can forward along to
# two different microservices, alpha and beta.
#
# Run with 'docker-compose up', then hit one of the two endpoints:
#
#   localhost:8080/app1 => alpha service
#   localhost:8080/app2 => beta service
#
# The services simply respond with plain text describing the services.
version: '3' # For modern Docker Compose...

services:           # Define services here
  web:              # The web service...
    image: nginx    # ... uses the publicly available nginx image
    volumes:        # ... and uses the included nginx.conf for proxy routing
      - ./nginx.conf:/etc/nginx/conf.d/default.conf
    ports:          
      - "8080:80"   # forward your port 8080 -> internal network's port 80
    depends_on:     # Don't start until both alpha and beta are up!
      - alpha
      - beta
  alpha:            # The alpha service...
    build: .        # ... is built using the Dockerfile in this directory
    environment:    # We set this variable, so the service prints out a unique name
      - MESSAGE=alpha
  beta:             # The beta service, same as alpha...
    build: .
    environment:
      - MESSAGE=beta

Dockerfile

# Temporary image to coordinate the build...
FROM golang:1.10-alpine
ADD service.go /go/src/service/service.go
RUN go install service

# The actual output image
FROM alpine:latest
COPY --from=0 /go/bin/service .
ENV PORT 8080
CMD ["./service"]

nginx.conf

server {
    listen 80;

    location /app1/ {
        proxy_pass http://alpha:8080;
    }

    location /app2/ {
        proxy_pass http://beta:8080;
    }
}

service.go

package main

import (
	"fmt"
	"log"
	"net/http"
	"os"
)

func main() {

	msg := os.Getenv("MESSAGE")
	if "" == msg {
		msg = "did not set MESSAGE environment variable"
	}

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "Hello from %s", msg)
	})

	log.Printf("Starting service %s", msg)
	log.Fatalln(http.ListenAndServe(":8080", nil))
}