feat(examples): Add nginx-golang compose example

This example is dervied from the nginx-golang
docker/awesome-compose example.

Signed-off-by: Luca Seritan <luca.seritan@gmail.com>

Author: LucaSeri

.github/workflows/examples-nginx-golang.yaml

@@ -0,0 +1,60 @@
+name: examples/nginx-golang
+
+on:
+  repository_dispatch:
+    types: [core_merge]
+
+  workflow_dispatch:
+
+  schedule:
+  - cron: '0 0 * * *' # Everyday at 12AM
+
+  push:
+    branches: [main]
+    paths:
+    - 'examples/compose/nginx-golang/**'
+    - '.github/workflows/examples-nginx-golang.yaml'
+    - '!examples/compose/nginx-golang/README.md'
+
+  pull_request:
+    types: [opened, synchronize, reopened]
+    branches: [main]
+    paths:
+    - 'examples/compose/nginx-golang/**'
+    - '.github/workflows/examples-nginx-golang.yaml'
+    - '!examples/compose/nginx-golang/README.md'
+
+jobs:
+  up:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Create Docker bridge network
+      run: docker network create my-bridge-network
+
+    - name: Check IP address
+      run: ip a s
+
+    - name: Compose up nginx-golang
+      run: |
+        set -xe
+
+        curl --proto '=https' --tlsv1.2 -sSf https://get.kraftkit.sh > script.sh
+        chmod +x script.sh
+        sudo ./script.sh -y
+
+        sudo kraft compose up -d
+      working-directory: examples/compose/nginx-golang
+
+    - name: Compose up nginx-golang
+      uses: unikraft/kraftkit@staging
+      with:
+        loglevel: debug
+        workdir: examples/compose/nginx-golang
+        runtimedir: /github/workspace/.kraftkit
+        run: |
+          set -xe
+
+          sudo kraft net create a

examples/compose/nginx-golang/README.md

@@ -0,0 +1,95 @@
+## Compose sample application
+
+### NGINX proxy with Go backend
+
+This example was derived from the [nginx-golang docker/awesome-compose example](https://github.com/docker/awesome-compose/tree/master/nginx-golang).
+
+Project structure:
+
+```bash
+.
+├── backend
+│   ├── Kraftfile
+│   ├── Dockerfile
+│   └── main.go
+├── compose.yaml
+├── proxy
+│   └── nginx.conf
+└── README.md
+```
+
+[`compose.yaml`](compose.yaml)
+
+```yml
+services:
+  proxy:
+    image: nginx:1.25
+    volumes:
+      - ./proxy:/etc/nginx
+    ports:
+      - 8080:80
+    depends_on:
+      - backend
+    networks:
+      internal:
+
+  backend:
+    build:
+      context: backend
+    networks:
+      internal:
+        ipv4_address: 172.23.0.2
+
+networks:
+  internal:
+    ipam:
+      config:
+        - subnet: 172.23.0.1/16
+```
+
+The compose file defines an application with two services `proxy` and `backend`.
+When deploying the application, kraft compose maps port 80 of the frontend service VM to port 8080 of the host as specified in the file.
+Make sure port 8080 on the host is not already in use.
+
+## Deploy with kraft compose
+
+```bash
+$ kraft compose up -d
+creating network nginx-golang_internal...
+nginx-golang_internal
+ i  building service backend...
+...
+nginx-golang-backend
+nginx-golang-proxy
+```
+
+## Expected result
+
+Listing VMs must show two VMs running and the port mapping as below:
+
+```bash
+$ kraft compose ps
+NAME                  KERNEL                          ARGS            CREATED         STATUS   MEM  PORTS                 PLAT
+nginx-golang-backend  oci://unikraft.org/base:latest  /server         23 seconds ago  running  64M                        qemu/x86_64
+nginx-golang-proxy    oci://nginx:1.25                /usr/bin/nginx  22 seconds ago  running  64M  0.0.0.0:8080->80/tcp  qemu/x86_64
+```
+
+After the application starts, navigate to `http://localhost:8080` in your web browser or run:
+
+```bash
+$ curl localhost:8080
+ .--------------------.
+( Hello from Unikraft! )
+ '--------------------'
+         \\
+          \\
+             _
+           c'o'o  .--.
+           (| |)_/
+```
+
+Stop and remove the VMs
+
+```bash
+kraft compose down
+```

examples/compose/nginx-golang/backend/Dockerfile

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+FROM golang:1.21.3-bookworm AS build
+
+WORKDIR /src
+
+COPY ./main.go /src/server.go
+
+COPY go.mod go.sum ./
+RUN --mount=type=cache,target=/go/pkg/mod/cache \
+    go mod download
+
+COPY . .
+
+RUN set -xe; \
+    CGO_ENABLED=1 \
+    go build \
+      -buildmode=pie \
+      -ldflags "-linkmode external -extldflags '-static-pie'" \
+      -tags netgo \
+      -o /server server.go \
+    ;
+
+FROM scratch
+
+COPY --from=build /server /server
+COPY --from=build /lib/x86_64-linux-gnu/libc.so.6 /lib/x86_64-linux-gnu/
+COPY --from=build /lib64/ld-linux-x86-64.so.2 /lib64/
+
+CMD ["/server"]

examples/compose/nginx-golang/backend/Kraftfile

@@ -0,0 +1,7 @@
+spec: v0.6
+
+runtime: base:latest
+
+rootfs: ./Dockerfile
+
+cmd: ["/server"]

examples/compose/nginx-golang/backend/go.mod

@@ -0,0 +1,5 @@
+module github.com/docker/awesome-compose/nginx-golang/backend
+
+go 1.18
+
+require github.com/go-chi/chi/v5 v5.0.7

examples/compose/nginx-golang/backend/go.sum

@@ -0,0 +1,2 @@
+github.com/go-chi/chi/v5 v5.0.7 h1:rDTPXLDHGATaeHvVlLcR4Qe0zftYethFucbjVQ1PxU8=
+github.com/go-chi/chi/v5 v5.0.7/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=

examples/compose/nginx-golang/backend/main.go

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+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
+)
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(
+		w, `
+ .--------------------.
+( Hello from Unikraft! )
+ '--------------------'
+         \\
+          \\
+             _
+           c'o'o  .--.
+           (| |)_/
+
+`,
+	)
+}
+
+func main() {
+	r := chi.NewRouter()
+	r.Use(middleware.Logger)
+	r.Get("/", handler)
+
+	fmt.Println("Go backend started!")
+	log.Fatal(http.ListenAndServe(":80", r))
+}

examples/compose/nginx-golang/compose.yaml

@@ -0,0 +1,25 @@
+---
+services:
+  proxy:
+    image: nginx:1.25
+    volumes:
+      - ./proxy:/etc/nginx
+    ports:
+      - 8080:80
+    depends_on:
+      - backend
+    networks:
+      internal:
+
+  backend:
+    build:
+      context: backend
+    networks:
+      internal:
+        ipv4_address: 172.23.0.2
+
+networks:
+  internal:
+    ipam:
+      config:
+        - subnet: 172.23.0.1/16

examples/compose/nginx-golang/proxy/nginx.conf

@@ -0,0 +1,26 @@
+worker_processes 1;
+daemon off;
+master_process off;
+user root root;
+
+events {
+  worker_connections 32;
+}
+
+http {
+  error_log stderr error;
+  access_log off;
+
+  keepalive_timeout     10s;
+  keepalive_requests    10000;
+  send_timeout          10s;
+
+  server {
+    listen 80;
+    server_name localhost;
+
+    location / {
+      proxy_pass http://172.23.0.2;
+    }
+  }
+}