appvm/appvm.go
2019-12-30 13:58:18 +00:00

423 lines
9.7 KiB
Go

/**
* @author Mikhail Klementev jollheef<AT>riseup.net
* @license GNU GPLv3
* @date July 2018
* @brief appvm launcher
*/
package main
import (
"bytes"
"errors"
"fmt"
"io"
"io/ioutil"
"log"
"net"
"os"
"os/exec"
"path/filepath"
"regexp"
"strconv"
"strings"
"syscall"
"time"
"github.com/digitalocean/go-libvirt"
"github.com/go-cmd/cmd"
"github.com/jollheef/go-system"
"github.com/olekukonko/tablewriter"
kingpin "gopkg.in/alecthomas/kingpin.v2"
)
func evalNix(expr string) (value string, err error) {
command := exec.Command("nix", "eval", "--raw", "(toString ("+expr+"))")
log.Print("Evaluating " + expr)
var stdout bytes.Buffer
command.Stdout = &stdout
err = command.Run()
value = stdout.String()
return
}
// Gets an expression returning AppVM config path
func getAppVMExpressionPath(name string) (paths []string, config string) {
paths = strings.Split(os.Getenv("NIX_PATH"), ":")
config = "nix/" + name + ".nix"
paths = append(paths, configDir)
for _, a := range paths {
searchpath := a
log.Print("Searching " + searchpath + " for expressions")
if _, err := os.Stat(searchpath); !os.IsNotExist(err) {
exprpath := searchpath + "/nix/" + name + ".nix"
log.Print("File exists?: ", exprpath)
if _, err := os.Stat(exprpath); !os.IsNotExist(err) {
log.Print("File exists: ", exprpath)
config = exprpath
return
}
}
log.Print("Local repo " + searchpath + " doesn't have a nix expression for " + name)
}
log.Print("Trying to use remote repo config")
rev := "1251a21abadc15b7187d485317434c9befd0f6b2"
fetchFormat := "(builtins.fetchTarball \"https://github.com/%[1]s/%[2]s/archive/" + rev + ".tar.gz\")"
splitString := strings.Split(name, "/")
if len(splitString) != 3 {
// nope, not a repo format
path, err := evalNix(fmt.Sprintf(fetchFormat, "jollheef", "appvm", name))
if err != nil {
log.Fatal("OH NO ", err)
return
}
paths = []string{path}
config = path + "/nix/" + name + ".nix"
return
}
return
}
func list(l *libvirt.Libvirt) {
domains, err := l.Domains()
if err != nil {
log.Fatal(err)
}
fmt.Println("Started VM:")
for _, d := range domains {
if strings.HasPrefix(d.Name, "appvm") {
fmt.Println("\t", d.Name[6:])
}
}
fmt.Println("\nAvailable VM:")
files, err := ioutil.ReadDir(configDir + "/nix")
if err != nil {
log.Fatal(err)
}
for _, f := range files {
switch f.Name() {
case "base.nix":
continue
case "local.nix":
continue
}
fmt.Println("\t", f.Name()[0:len(f.Name())-4])
}
}
func copyFile(from, to string) (err error) {
source, err := os.Open(from)
if err != nil {
return
}
defer source.Close()
destination, err := os.Create(to)
if err != nil {
return
}
_, err = io.Copy(destination, source)
if err != nil {
destination.Close()
return
}
return destination.Close()
}
func prepareTemplates(appvmPath string) (err error) {
if _, err = os.Stat(appvmPath + "/nix/local.nix"); os.IsNotExist(err) {
err = ioutil.WriteFile(configDir+"/nix/local.nix", local_nix_template, 0644)
if err != nil {
return
}
}
return
}
func streamStdOutErr(command *cmd.Cmd) {
for {
select {
case line := <-command.Stdout:
fmt.Println(line)
case line := <-command.Stderr:
fmt.Fprintln(os.Stderr, line)
}
}
}
func generateVM(name string, verbose bool) (realpath, reginfo, qcow2 string, err error) {
paths, config := getAppVMExpressionPath(name)
nixargs := []string{
"<nixpkgs/nixos>",
"-A", "config.system.build.vm",
"-I", "nixos-config=" + config,
// Taking local config from home folder
"-I" + os.Getenv("HOME"),
}
for _, path := range paths {
nixargs = append(nixargs, "-I", path)
}
command := cmd.NewCmdOptions(cmd.Options{Buffered: false, Streaming: true},
"nix-build",
nixargs...,
)
if verbose {
go streamStdOutErr(command)
}
status := <-command.Start()
if status.Error != nil || status.Exit != 0 {
log.Println(status.Error, status.Stdout, status.Stderr)
if status.Error != nil {
err = status.Error
} else {
s := fmt.Sprintf("ret code: %d, out: %v, err: %v",
status.Exit, status.Stdout, status.Stderr)
err = errors.New(s)
}
return
}
realpath, err = filepath.EvalSymlinks("result/system")
if err != nil {
return
}
bytes, err := ioutil.ReadFile("result/bin/run-nixos-vm")
if err != nil {
return
}
match := regexp.MustCompile("regInfo=.*/registration").FindSubmatch(bytes)
if len(match) != 1 {
err = errors.New("should be one reginfo")
return
}
reginfo = string(match[0])
syscall.Unlink("result")
qcow2 = os.Getenv("HOME") + "/appvm/.fake.qcow2"
if _, err = os.Stat(qcow2); os.IsNotExist(err) {
system.System("qemu-img", "create", "-f", "qcow2", qcow2, "512M")
err = os.Chmod(qcow2, 0400) // qemu run with -snapshot, we only need it for create /dev/vda
if err != nil {
return
}
}
return
}
func isRunning(l *libvirt.Libvirt, name string) bool {
_, err := l.DomainLookupByName("appvm_" + name) // yep, there is no libvirt error handling
// VM is destroyed when stop so NO VM means STOPPED
return err == nil
}
func generateAppVM(l *libvirt.Libvirt, appvmPath, name string, verbose bool) (err error) {
err = os.Chdir(appvmPath)
if err != nil {
return
}
realpath, reginfo, qcow2, err := generateVM(name, verbose)
if err != nil {
return
}
sharedDir := fmt.Sprintf(os.Getenv("HOME") + "/appvm/" + name)
os.MkdirAll(sharedDir, 0700)
xml := generateXML(name, realpath, reginfo, qcow2, sharedDir)
_, err = l.DomainCreateXML(xml, libvirt.DomainStartValidate)
return
}
func stupidProgressBar() {
const length = 70
for {
time.Sleep(time.Second / 4)
fmt.Printf("\r%s]\r[", strings.Repeat(" ", length))
for i := 0; i <= length-2; i++ {
time.Sleep(time.Second / 20)
fmt.Printf("+")
}
}
}
func start(l *libvirt.Libvirt, name string, verbose bool) {
appvmPath := configDir
// Copy templates
err := prepareTemplates(appvmPath)
if err != nil {
log.Fatal(err)
}
if !isRunning(l, name) {
if !verbose {
go stupidProgressBar()
}
err = generateAppVM(l, appvmPath, name, verbose)
if err != nil {
log.Fatal(err)
}
}
cmd := exec.Command("virt-viewer", "-c", "qemu:///system", "appvm_"+name)
cmd.Start()
}
func stop(l *libvirt.Libvirt, name string) {
dom, err := l.DomainLookupByName("appvm_" + name)
if err != nil {
if libvirt.IsNotFound(err) {
log.Println("Appvm not found or already stopped")
return
} else {
log.Fatal(err)
}
}
err = l.DomainShutdown(dom)
if err != nil {
log.Fatal(err)
}
}
func drop(name string) {
appDataPath := fmt.Sprintf(os.Getenv("HOME") + "/appvm/" + name)
os.RemoveAll(appDataPath)
}
func autoBalloon(l *libvirt.Libvirt, memoryMin, adjustPercent uint64) {
domains, err := l.Domains()
if err != nil {
log.Fatal(err)
}
table := tablewriter.NewWriter(os.Stdout)
table.SetHeader([]string{"Application VM", "Used memory", "Current memory", "Max memory", "New memory"})
for _, d := range domains {
if strings.HasPrefix(d.Name, "appvm_") {
name := d.Name[6:]
memoryUsedRaw, err := ioutil.ReadFile(os.Getenv("HOME") + "/appvm/" + name + "/.memory_used")
if err != nil {
log.Fatal(err)
}
memoryUsedMiB, err := strconv.Atoi(string(memoryUsedRaw[0 : len(memoryUsedRaw)-1]))
if err != nil {
log.Fatal(err)
}
memoryUsed := memoryUsedMiB * 1024
_, memoryMax, memoryCurrent, _, _, err := l.DomainGetInfo(d)
if err != nil {
log.Fatal(err)
}
memoryNew := uint64(float64(memoryUsed) * (1 + float64(adjustPercent)/100))
if memoryNew > memoryMax {
memoryNew = memoryMax - 1
}
if memoryNew < memoryMin {
memoryNew = memoryMin
}
err = l.DomainSetMemory(d, memoryNew)
if err != nil {
log.Fatal(err)
}
table.Append([]string{name,
fmt.Sprintf("%d", memoryUsed),
fmt.Sprintf("%d", memoryCurrent),
fmt.Sprintf("%d", memoryMax),
fmt.Sprintf("%d", memoryNew)})
}
}
table.Render()
}
var configDir = os.Getenv("HOME") + "/.config/appvm/"
func main() {
os.Mkdir(os.Getenv("HOME")+"/appvm", 0700)
os.MkdirAll(configDir+"/nix", 0700)
err := ioutil.WriteFile(configDir+"/nix/base.nix", base_nix, 0644)
if err != nil {
log.Fatal(err)
}
c, err := net.DialTimeout("unix", "/var/run/libvirt/libvirt-sock", time.Second)
if err != nil {
log.Fatal(err)
}
l := libvirt.New(c)
if err := l.Connect(); err != nil {
log.Fatal(err)
}
defer l.Disconnect()
kingpin.Command("list", "List applications")
autoballonCommand := kingpin.Command("autoballoon", "Automatically adjust/reduce app vm memory")
minMemory := autoballonCommand.Flag("min-memory", "Set minimal memory (megabytes)").Default("1024").Uint64()
adjustPercent := autoballonCommand.Flag("adj-memory", "Adjust memory amount (percents)").Default("20").Uint64()
startCommand := kingpin.Command("start", "Start application")
startName := startCommand.Arg("name", "Application name").Required().String()
startVerbose := startCommand.Flag("verbose", "Increase verbosity").Default("False").Bool()
stopName := kingpin.Command("stop", "Stop application").Arg("name", "Application name").Required().String()
dropName := kingpin.Command("drop", "Remove application data").Arg("name", "Application name").Required().String()
generateCommand := kingpin.Command("generate", "Generate appvm definition")
generateName := generateCommand.Arg("name", "Nix package name").Required().String()
generateBin := generateCommand.Arg("bin", "Binary").Default("").String()
generateVMName := generateCommand.Flag("vm", "Use VM Name").Default("").String()
switch kingpin.Parse() {
case "list":
list(l)
case "generate":
generate(l, *generateName, *generateBin, *generateVMName)
case "start":
start(l, *startName, *startVerbose)
case "stop":
stop(l, *stopName)
case "drop":
drop(*dropName)
case "autoballoon":
autoBalloon(l, *minMemory*1024, *adjustPercent)
}
}