appvm/generate.go
2020-01-04 11:23:40 +00:00

195 lines
3.9 KiB
Go

package main
import (
"errors"
"fmt"
"io/ioutil"
"log"
"os"
"os/exec"
"strings"
"github.com/digitalocean/go-libvirt"
)
var template = `
{pkgs, ...}:
let
application = "${pkgs.%s}/bin/%s";
appRunner = pkgs.writeShellScriptBin "app" ''
ARGS_FILE=/home/user/.args
ARGS=$(cat $ARGS_FILE)
rm $ARGS_FILE
${application} $ARGS
systemctl poweroff
'';
in {
imports = [
<nixpkgs/nixos/modules/virtualisation/qemu-vm.nix>
<nix/base.nix>
];
services.xserver.displayManager.sessionCommands = "${appRunner}/bin/app &";
}
`
func isPackageExists(channel, name string) bool {
return nil == exec.Command("nix-build", "<"+channel+">", "-A", name).Run()
}
func nixPath(name string) (path string, err error) {
command := exec.Command("nix", "path-info", name)
bytes, err := command.Output()
if err != nil {
return
}
path = string(bytes)
return
}
func guessChannel() (channel string, err error) {
command := exec.Command("nix-channel", "--list")
bytes, err := command.Output()
if err != nil {
return
}
channels := strings.Split(string(bytes), "\n")
for _, line := range channels {
fields := strings.Fields(line)
if len(fields) == 2 {
if strings.Contains(fields[1], "nixos.org/channels") {
channel = fields[0]
return
}
}
}
err = errors.New("No channel found")
return
}
func filterDotfiles(files []os.FileInfo) (notHiddenFiles []os.FileInfo) {
for _, f := range files {
if !strings.HasPrefix(f.Name(), ".") {
notHiddenFiles = append(notHiddenFiles, f)
}
}
return
}
func generate(l *libvirt.Libvirt, pkg, bin, vmname string) (err error) {
// TODO refactor
var name, channel string
if strings.Contains(pkg, ".") {
channel = strings.Split(pkg, ".")[0]
name = strings.Join(strings.Split(pkg, ".")[1:], ".")
} else {
log.Println("Package name does not contains channel")
log.Println("Trying to guess")
channel, err = guessChannel()
if err != nil {
log.Println("Cannot guess channel")
log.Println("Check nix-channel --list")
log.Println("Will try <nixpkgs>")
channel = "nixpkgs"
err = nil
}
name = pkg
log.Println("Use", channel+"."+pkg)
}
if !isPackageExists(channel, name) {
s := "Package " + name + " does not exists"
err = errors.New(s)
log.Println(s)
return
}
path, err := nixPath(channel + "." + name)
if err != nil {
log.Println("Cannot find nix path")
return
}
path = strings.TrimSpace(path)
files, err := ioutil.ReadDir(path + "/bin/")
if err != nil {
log.Println(err)
return
}
if bin == "" && len(files) != 1 {
fmt.Println("There's more than one binary in */bin")
fmt.Println("Files in", path+"/bin/:")
for _, f := range files {
fmt.Println("\t", f.Name())
}
log.Println("Trying to guess binary")
var found bool = false
notHiddenFiles := filterDotfiles(files)
if len(notHiddenFiles) == 1 {
log.Println("Use", notHiddenFiles[0].Name())
bin = notHiddenFiles[0].Name()
found = true
}
if !found {
for _, f := range files {
parts := strings.Split(pkg, ".")
if f.Name() == parts[len(parts)-1] {
log.Println("Use", f.Name())
bin = f.Name()
found = true
}
}
}
if !found {
log.Println("Cannot guess in */bin, " +
"you should specify one of them explicitly")
return
}
}
if bin != "" {
var found bool = false
for _, f := range files {
if bin == f.Name() {
found = true
}
}
if !found {
log.Println("There's no such file in */bin")
return
}
} else {
bin = files[0].Name()
}
var appFilename string
if vmname != "" {
appFilename = configDir + "/nix/" + vmname + ".nix"
} else {
appFilename = configDir + "/nix/" + name + ".nix"
}
appNixConfig := fmt.Sprintf(template, name, bin)
err = ioutil.WriteFile(appFilename, []byte(appNixConfig), 0600)
if err != nil {
log.Println(err)
return
}
fmt.Print(appNixConfig + "\n")
log.Println("Configuration file is saved to", appFilename)
return
}