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|
package main
import (
"bytes"
"flag"
"fmt"
"log"
"os"
"os/exec"
"path/filepath"
"strings"
"time"
)
const (
workbench = `build`
)
var (
key = ""
repo = ""
commit = ""
task = ""
image = ""
port = ""
)
func init() {
flag.StringVar(&key, "key", "", "Path to SSH private key")
flag.StringVar(&repo, "repo", "", "Source code as valid Git URL")
flag.StringVar(&commit, "commit", "", "Commit or commit-ish reference for checkout")
flag.StringVar(&task, "task", "", "Shell code to execute for the build")
flag.StringVar(&image, "image", "", "QEMU qcow2 image which contains the VM")
flag.StringVar(&port, "port", "", "localhost port which is connected to VM SSH server")
}
func main() {
flag.Parse()
log.SetFlags(0)
log.Println("Starting craft")
defer log.Println("Exiting craft")
vm := qemu()
err := vm.Start()
if err != nil {
log.Fatal(err)
}
defer func() {
err := vm.Process.Kill()
if err != nil {
log.Fatal(err)
}
}()
waitBoot()
checkoutSources(repo, commit)
craft()
}
func runCommand(name string, args ...string) {
log.Printf("Remote execution: %s %s\n", name, strings.Join(args, " "))
command := sshCommand(name, args...)
command.Stderr = os.Stderr
command.Stdout = os.Stdout
err := command.Run()
if err != nil {
log.Fatal(err)
}
}
func qemu() *exec.Cmd {
return exec.Command(
"qemu-system-x86_64",
"-enable-kvm",
"-m",
"4G",
"-net",
"nic,model=virtio",
"-net",
fmt.Sprintf(
"user,hostfwd=tcp:127.0.0.1:%s-:22",
port,
),
"-drive",
fmt.Sprintf(
"file=%s,media=disk,snapshot=on,if=virtio",
image,
),
"-smp",
"cpus=4",
"-nographic",
)
}
func sshCommand(name string, arg ...string) *exec.Cmd {
return exec.Command(
"ssh",
append([]string{
"-p",
port,
"-o",
"UserKnownHostsFile=/dev/null",
"-o",
"StrictHostKeyChecking=no",
"-i",
key,
"root@localhost",
name,
}, arg...)...,
)
}
func waitBoot() {
retries := 5
initialDelay := 1 * time.Second
log.Println("Waiting for VM to boot")
time.Sleep(initialDelay) // without that `ssh` returns too quickly
for range retries {
cmd := sshCommand("true")
err := cmd.Run()
if err == nil {
log.Println("VM booted")
return
}
}
log.Fatalf("Could not reach VM %d times - giving up", retries)
}
func craft() {
script := fmt.Sprintf(`#!/bin/sh
cd %s
%s
`, workbench, task)
cmd := sshCommand("sh")
cmd.Stdin = bytes.NewBufferString(script)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
if err != nil {
log.Fatal(err)
}
}
func checkoutSources(repo string, commit string) string {
runCommand(
"git",
"clone",
repo,
workbench,
)
runCommand(
"git",
"--git-dir",
filepath.Join(workbench, ".git"),
"--work-tree",
workbench,
"checkout",
commit,
)
runCommand(
"git",
"-C",
workbench,
"submodule",
"update",
"--depth=1",
"--init",
"--recursive",
)
return workbench
}
|
