Qemu debian image generator

tools/qemu-debian-img/main.go

@@ -0,0 +1,181 @@
+// Copyright 2018 Mikhail Klementev. All rights reserved.
+// Use of this source code is governed by a GPLv3 license
+// (or later) that can be found in the LICENSE file.
+
+package main
+
+import (
+	"errors"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"os/user"
+	"regexp"
+	"strings"
+
+	system "github.com/jollheef/go-system"
+	kingpin "gopkg.in/alecthomas/kingpin.v2"
+)
+
+func matchBody(url, pattern string) bool {
+	resp, err := http.Get(url)
+	if err != nil {
+		return false
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return false
+	}
+
+	matched, err := regexp.MatchString(pattern, string(body))
+	if err != nil {
+		return false
+	}
+	if !matched {
+		return false
+	}
+
+	return true
+}
+
+func isAptCacherExists(url string) bool {
+	return matchBody(url, "Apt-Cacher")
+}
+
+func runInChroot(chroot, cmd string) (string, string, int, error) {
+	return system.System("chroot", chroot, "/bin/sh", "-c", cmd)
+}
+
+func generateImage(repo, release, path, size string) (err error) {
+	log.Println("Check current user")
+	usr, err := user.Current()
+	if err != nil {
+		return
+	}
+	if usr.Name != "root" {
+		err = errors.New("Run as root is required")
+		return
+	}
+
+	log.Println("Create qcow2 image")
+	stdout, stderr, _, err := system.System("qemu-img", "create", path, size)
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+
+	log.Println("Create ext4 file system")
+	stdout, stderr, _, err = system.System("mkfs.ext4", "-F", path)
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+
+	log.Println("Create temporary directory")
+	stdout, stderr, _, err = system.System("mktemp", "-d")
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+	tmpdir := strings.TrimSpace(stdout)
+	defer func() {
+		log.Println("Remove temporary directory")
+		err := os.RemoveAll(tmpdir)
+		if err != nil {
+			log.Println(err)
+		}
+	}()
+
+	log.Println("Mount qemu image")
+	stdout, stderr, _, err = system.System("mount", "-o", "loop", path, tmpdir)
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+	defer func() {
+		log.Println("Umount qemu image")
+		stdout, stderr, _, err := system.System("umount", tmpdir)
+		if err != nil {
+			log.Println(err, stdout, stderr)
+		}
+	}()
+
+	log.Println("debootstrap (may be more than 10-15 minutes)")
+	stdout, stderr, _, err = system.System("debootstrap",
+		"--include=openssh-server",
+		release, tmpdir, repo)
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+
+	log.Println("Create new user")
+	stdout, stderr, _, err = runInChroot(tmpdir, "useradd -m user")
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+
+	log.Println("Login without password")
+	stdout, stderr, _, err = runInChroot(tmpdir, "passwd -d root")
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+	stdout, stderr, _, err = runInChroot(tmpdir, "passwd -d user")
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+
+	log.Println("Allow ssh login without password (NOTE: fixed sshd pam.d)")
+	stdout, stderr, _, err = runInChroot(tmpdir,
+		"echo auth sufficient pam_permit.so > /etc/pam.d/sshd"+
+			" && echo PermitEmptyPasswords yes >> /etc/ssh/sshd_config"+
+			" && echo PermitRootLogin yes >> /etc/ssh/sshd_config")
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+
+	log.Println("Add dhclient to rc.local")
+	stdout, stderr, _, err = runInChroot(tmpdir,
+		"echo '#!/bin/sh\ndhclient' >> /etc/rc.local"+
+			" && chmod +x /etc/rc.local")
+	if err != nil {
+		log.Println(stdout, stderr)
+		return
+	}
+
+	return
+}
+
+func main() {
+	generate := kingpin.Command("generate", "Generate qemu image")
+	repository := generate.Flag("repository", "Debian/ubuntu repository").Default(
+		"deb.debian.org/debian").String()
+	aptCacherURL := generate.Flag("apt-cacher", "Local apt cacher url").Default(
+		"http://localhost:3142/").String()
+	release := generate.Flag("release", "Debian/ubuntu release name").Default(
+		"sid").String()
+	size := generate.Flag("size", "Image size").Default("8G").String()
+	path := generate.Arg("path", "Generated image path").Required().String()
+
+	switch kingpin.Parse() {
+	case "generate":
+		repo := *repository
+		if isAptCacherExists(*aptCacherURL) {
+			log.Println("Use local apt cache")
+			repo = *aptCacherURL + "/" + repo
+		}
+		log.Println("Repository:", repo)
+
+		err := generateImage(repo, *release, *path, *size)
+		if err != nil {
+			log.Fatalln(err)
+		}
+	}
+}