docker-compose.yml

version: "3.8"
services:

  front-envoy:
    build:
      context: .
      dockerfile: envoy.Dockerfile
      args:
        ENVOY_NAME: front-envoy
    volumes:
      - ./front-envoy.yaml:/etc/front-envoy.yaml
    networks:
      envoynet:
        aliases:
          - front-envoy
    expose:
      - "80"
    ports:
      - "8080:80"

  shadow-envoy:
    build:
      context: .
      dockerfile: envoy.Dockerfile
      args:
        ENVOY_NAME: shadow-envoy
    volumes:
      - ./shadow-envoy.yaml:/etc/shadow-envoy.yaml
    networks:
      envoynet:
        aliases:
          - shadow-envoy
    expose:
      - "80"
    ports:
      - "8081:80"


  staging-envoy:
    build:
      context: .
      dockerfile: envoy.Dockerfile
      args:
        ENVOY_NAME: staging-envoy
    volumes:
      - ./staging-envoy.yaml:/etc/staging-envoy.yaml
    networks:
      envoynet:
        aliases:
          - staging-envoy
    expose:
      - "80"
    ports:
      - "8082:80"

  echo-v1:
    build:
      context: ./echo-service
      dockerfile: echo.Dockerfile 
    environment:
      - VERSION=1
    networks:
      envoynet:
        aliases:
          - echo-v1
    expose:
      - "7000"
    ports:
      - "7001:7000"

  echo-v2:
    build:
      context: ./echo-service
      dockerfile: echo.Dockerfile
    environment:
      - VERSION=2
    networks:
      envoynet:
        aliases:
          - echo-v2
    expose:
      - "7000"
    ports:
      - "7002:7000"

  echo-v3:
    build:
      context: ./echo-service
      dockerfile: echo.Dockerfile
    environment:
      - VERSION=3
    networks:
      envoynet:
        aliases:
          - echo-v3
    expose:
      - "7000"
    ports:
      - "7003:7000"

networks:
  envoynet: {}

echo.Dockerfile

FROM golang:1.15.0 AS build
ADD . /src
RUN  cd /src && CGO_ENABLED=0 \
     GOOS=linux \
     GOARCH=amd64 \
     go build -o echo

FROM alpine:3.11
WORKDIR /app
COPY --from=build /src/echo /app/
ENTRYPOINT /app/echo

echo.go

package main

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

var hostname string
var version string

func main() {
	var err error
	hostname, err = os.Hostname()
	version = os.Getenv("VERSION")

	http.HandleFunc("/", echoHandler)
	log.Println("Listening on :7000")
	err = http.ListenAndServe(":7000", nil)
	if err != nil {
		log.Fatalf("Failed to listen and serve on port 7000, %s", err.Error())
	}
}

func echoHandler(w http.ResponseWriter, r *http.Request) {
	requestDump, err := httputil.DumpRequest(r, true)
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println(string(requestDump))
	_, err = w.Write([]byte(fmt.Sprintf("[%s] Version: v%s\n%s\n", hostname, version, requestDump)))
	if err != nil {
		log.Printf("Failed to write response, %s", err.Error())
	}
}

envoy.Dockerfile

FROM envoyproxy/envoy:v1.14.4

RUN apt update && apt install -y curl

ARG ENVOY_NAME
ENV ENVOY_NAME ${ENVOY_NAME}

CMD /usr/local/bin/envoy -c /etc/${ENVOY_NAME}.yaml -l debug --service-cluster ${ENVOY_NAME}

front-envoy.yaml

static_resources:
  listeners:
  - address:
      socket_address:
        address: 0.0.0.0
        port_value: 80
    filter_chains:
    - filters:
      - name: envoy.http_connection_manager
        typed_config:
          "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
          codec_type: auto
          stat_prefix: ingress_http
          route_config:
            name: local_route
            virtual_hosts:
            - name: echo-services
              domains:
              - "echo.org.com"
              routes:
              - match:
                  prefix: "/v1/echo"
                route:
                  cluster: echoV1
                  request_mirror_policies:
                    cluster: shadow-envoy
                    runtime_fraction: { default_value: { numerator: 100 } }
                request_headers_to_add:
                  - header:
                      key: "X-SHADOW-HOST"
                      value: "echo.stg.org.com"
                    append: false
              - match:
                  prefix: "/v2/echo"
                route:
                  cluster: echoV2
          http_filters:
          - name: envoy.router
            typed_config: {}
    access_log:
    - name: envoy.access_loggers.file
      typed_config:
        "@type": type.googleapis.com/envoy.extensions.access_loggers.file.v3.FileAccessLog
        path: "/dev/stdout"
  clusters:
  - name: echoV1
    connect_timeout: 0.25s
    type: strict_dns
    lb_policy: round_robin
    load_assignment:
      cluster_name: echoV1
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: echo-v1
                port_value: 7000
  - name: echoV2
    connect_timeout: 0.25s
    type: strict_dns
    lb_policy: round_robin
    load_assignment:
      cluster_name: echoV2
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: echo-v2
                port_value: 7000

  - name: shadow-envoy
    connect_timeout: 0.25s
    type: strict_dns
    lb_policy: round_robin
    http2_protocol_options: {}
    load_assignment:
      cluster_name: shadow-envoy
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: shadow-envoy
                port_value: 80
admin:
  access_log_path: "/dev/null"
  address:
    socket_address:
      address: 0.0.0.0
      port_value: 8001

shadow-envoy.yaml

static_resources:
  listeners:
  - address:
      socket_address:
        address: 0.0.0.0
        port_value: 80
    filter_chains:
    - filters:
      - name: envoy.http_connection_manager
        typed_config:
          "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
          codec_type: auto
          stat_prefix: ingress_http
          route_config:
            name: local_route
            virtual_hosts:
            - name: forward-staging
              domains:
              - "*"
              routes:
              - match:
                  prefix: "/"
                route:
                  cluster: staging-envoy
                  host_rewrite_header: X-SHADOW-HOST
                response_headers_to_remove:
                  - X-SHADOW-HOST
          http_filters:
          - name: envoy.router
            typed_config: {}
    access_log:
    - name: envoy.access_loggers.file
      typed_config:
        "@type": type.googleapis.com/envoy.extensions.access_loggers.file.v3.FileAccessLog
        path: "/dev/stdout"
  clusters:
  - name: staging-envoy
    connect_timeout: 0.25s
    type: strict_dns
    lb_policy: round_robin
    http2_protocol_options: {}
    load_assignment:
      cluster_name: staging-envoy
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: staging-envoy
                port_value: 80
admin:
  access_log_path: "/dev/null"
  address:
    socket_address:
      address: 0.0.0.0
      port_value: 8001

staging-envoy.yaml

static_resources:
  listeners:
  - address:
      socket_address:
        address: 0.0.0.0
        port_value: 80
    filter_chains:
    - filters:
      - name: envoy.http_connection_manager
        typed_config:
          "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
          codec_type: auto
          stat_prefix: ingress_http
          route_config:
            name: local_route
            virtual_hosts:
            - name: echo-services
              domains:
              - "echo.stg.org.com"
              routes:
              - match:
                  prefix: "/"
                route:
                  cluster: testing-echoV3
          http_filters:
          - name: envoy.router
            typed_config: {}
    access_log:
    - name: envoy.access_loggers.file
      typed_config:
        "@type": type.googleapis.com/envoy.extensions.access_loggers.file.v3.FileAccessLog
        path: "/dev/stdout"
  clusters:
  - name: testing-echoV3
    connect_timeout: 0.25s
    type: strict_dns
    lb_policy: round_robin
    load_assignment:
      cluster_name: testing-echoV3
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: echo-v3
                port_value: 7000
admin:
  access_log_path: "/dev/null"
  address:
    socket_address:
      address: 0.0.0.0
      port_value: 8001